From 37e2786c5e55595e56e07d2bcd6e8514d0c5899d Mon Sep 17 00:00:00 2001
From: hunicus <93150691+hunicus@users.noreply.github.com>
Date: Thu, 24 Mar 2022 08:55:20 -0400
Subject: [PATCH 01/17] Add faq tab placeholder

---
 frontend/src/app/app-routing.module.ts          |  4 ++++
 .../src/app/components/docs/docs.component.html | 17 +++++++++++++----
 .../src/app/components/docs/docs.component.ts   | 11 ++++++++++-
 3 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/frontend/src/app/app-routing.module.ts b/frontend/src/app/app-routing.module.ts
index 003bbcf0d..37fb1d62d 100644
--- a/frontend/src/app/app-routing.module.ts
+++ b/frontend/src/app/app-routing.module.ts
@@ -127,6 +127,10 @@ let routes: Routes = [
         path: 'docs/api/:type',
         component: DocsComponent
       },
+      {
+        path: 'docs/faq',
+        component: DocsComponent
+      },
       {
         path: 'docs/api',
         redirectTo: 'docs/api/rest'
diff --git a/frontend/src/app/components/docs/docs.component.html b/frontend/src/app/components/docs/docs.component.html
index 8dc4a9e72..d6b43f064 100644
--- a/frontend/src/app/components/docs/docs.component.html
+++ b/frontend/src/app/components/docs/docs.component.html
@@ -4,9 +4,18 @@
     <h2 i18n="documentation.title">Documentation</h2>
 
     <ul ngbNav #nav="ngbNav" [(activeId)]="activeTab" class="nav-tabs">
+    
+      <li [ngbNavItem]="0" *ngIf="showFaqTab">
+        <a ngbNavLink routerLink="/docs/faq">FAQ</a>
+        <ng-template ngbNavContent>
 
-      <li [ngbNavItem]="0">
-        <a ngbNavLink routerLink="../rest">API - REST</a>
+          <p>FAQ placeholder</p>
+
+        </ng-template>
+      </li>
+
+      <li [ngbNavItem]="1">
+        <a ngbNavLink routerLink="/docs/api/rest">API - REST</a>
         <ng-template ngbNavContent>
 
           <app-api-docs [restTabActivated]="true"></app-api-docs>
@@ -14,8 +23,8 @@
         </ng-template>
       </li>
 
-      <li [ngbNavItem]="1" *ngIf="showWebSocketTab">
-        <a ngbNavLink routerLink="../websocket">API - WebSocket</a>
+      <li [ngbNavItem]="2" *ngIf="showWebSocketTab">
+        <a ngbNavLink routerLink="/docs/api/websocket">API - WebSocket</a>
         <ng-template ngbNavContent>
 
           <app-api-docs [restTabActivated]="false"></app-api-docs>
diff --git a/frontend/src/app/components/docs/docs.component.ts b/frontend/src/app/components/docs/docs.component.ts
index 605a453ab..f75900dc2 100644
--- a/frontend/src/app/components/docs/docs.component.ts
+++ b/frontend/src/app/components/docs/docs.component.ts
@@ -12,6 +12,7 @@ export class DocsComponent implements OnInit {
   activeTab = 0;
   env: Env;
   showWebSocketTab = true;
+  showFaqTab = true;
 
   constructor(
     private route: ActivatedRoute,
@@ -20,8 +21,16 @@ export class DocsComponent implements OnInit {
 
   ngOnInit(): void {
     const url = this.route.snapshot.url;
-    this.activeTab = ( url[2].path === "rest" ) ? 0 : 1;
+    if( url[1].path === "faq" ) {
+        this.activeTab = 0;
+    } else if( url[2].path === "rest" ) {
+        this.activeTab = 1;    
+    } else {
+        this.activeTab = 2;
+    }
+    
     this.env = this.stateService.env;
     this.showWebSocketTab = ( ! ( ( this.env.BASE_MODULE === "bisq" ) || ( this.stateService.network === "bisq" ) || ( this.stateService.network === "liquidtestnet" ) ) );
+    this.showFaqTab = ( ( this.stateService.network === "" ) || ( this.stateService.network === "signet" ) || ( this.stateService.network === "testnet" ) ) ? true : false;
   }
 }

From 61faf316446aa76e3aabd82a288d8fd27d73c64e Mon Sep 17 00:00:00 2001
From: hunicus <93150691+hunicus@users.noreply.github.com>
Date: Thu, 24 Mar 2022 10:38:32 -0400
Subject: [PATCH 02/17] Fix routing for faq tab

Make API links relative + add routing for signet and
testnet.
---
 frontend/src/app/app-routing.module.ts               | 8 ++++++++
 frontend/src/app/components/docs/docs.component.html | 8 ++++----
 frontend/src/app/components/docs/docs.component.ts   | 8 ++++----
 3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/frontend/src/app/app-routing.module.ts b/frontend/src/app/app-routing.module.ts
index 37fb1d62d..713fec384 100644
--- a/frontend/src/app/app-routing.module.ts
+++ b/frontend/src/app/app-routing.module.ts
@@ -274,6 +274,10 @@ let routes: Routes = [
             path: 'docs/api/:type',
             component: DocsComponent
           },
+          {
+            path: 'docs/faq',
+            component: DocsComponent
+          },
           {
             path: 'docs/api',
             redirectTo: 'docs/api/rest'
@@ -410,6 +414,10 @@ let routes: Routes = [
             path: 'docs/api/:type',
             component: DocsComponent
           },
+          {
+            path: 'docs/faq',
+            component: DocsComponent
+          },
           {
             path: 'docs/api',
             redirectTo: 'docs/api/rest'
diff --git a/frontend/src/app/components/docs/docs.component.html b/frontend/src/app/components/docs/docs.component.html
index d6b43f064..21d6ca93e 100644
--- a/frontend/src/app/components/docs/docs.component.html
+++ b/frontend/src/app/components/docs/docs.component.html
@@ -4,9 +4,9 @@
     <h2 i18n="documentation.title">Documentation</h2>
 
     <ul ngbNav #nav="ngbNav" [(activeId)]="activeTab" class="nav-tabs">
-    
+
       <li [ngbNavItem]="0" *ngIf="showFaqTab">
-        <a ngbNavLink routerLink="/docs/faq">FAQ</a>
+        <a ngbNavLink [routerLink]="['/docs/faq' | relativeUrl]">FAQ</a>
         <ng-template ngbNavContent>
 
           <p>FAQ placeholder</p>
@@ -15,7 +15,7 @@
       </li>
 
       <li [ngbNavItem]="1">
-        <a ngbNavLink routerLink="/docs/api/rest">API - REST</a>
+        <a ngbNavLink [routerLink]="['/docs/api/rest' | relativeUrl]">API - REST</a>
         <ng-template ngbNavContent>
 
           <app-api-docs [restTabActivated]="true"></app-api-docs>
@@ -24,7 +24,7 @@
       </li>
 
       <li [ngbNavItem]="2" *ngIf="showWebSocketTab">
-        <a ngbNavLink routerLink="/docs/api/websocket">API - WebSocket</a>
+        <a ngbNavLink [routerLink]="['/docs/api/websocket' | relativeUrl]">API - WebSocket</a>
         <ng-template ngbNavContent>
 
           <app-api-docs [restTabActivated]="false"></app-api-docs>
diff --git a/frontend/src/app/components/docs/docs.component.ts b/frontend/src/app/components/docs/docs.component.ts
index f75900dc2..042ed435b 100644
--- a/frontend/src/app/components/docs/docs.component.ts
+++ b/frontend/src/app/components/docs/docs.component.ts
@@ -24,13 +24,13 @@ export class DocsComponent implements OnInit {
     if( url[1].path === "faq" ) {
         this.activeTab = 0;
     } else if( url[2].path === "rest" ) {
-        this.activeTab = 1;    
+        this.activeTab = 1;
     } else {
         this.activeTab = 2;
     }
-    
+
     this.env = this.stateService.env;
-    this.showWebSocketTab = ( ! ( ( this.env.BASE_MODULE === "bisq" ) || ( this.stateService.network === "bisq" ) || ( this.stateService.network === "liquidtestnet" ) ) );
-    this.showFaqTab = ( ( this.stateService.network === "" ) || ( this.stateService.network === "signet" ) || ( this.stateService.network === "testnet" ) ) ? true : false;
+    this.showWebSocketTab = ( ! ( ( this.stateService.network === "bisq" ) || ( this.stateService.network === "liquidtestnet" ) ) );
+    this.showFaqTab = ( this.env.BASE_MODULE === 'mempool' ) ? true : false;
   }
 }

From 289ed7b9b3372cc9041cd9a5af948af49151e28d Mon Sep 17 00:00:00 2001
From: hunicus <93150691+hunicus@users.noreply.github.com>
Date: Thu, 24 Mar 2022 10:52:50 -0400
Subject: [PATCH 03/17] Make faq tab default when navigating to docs

---
 frontend/src/app/app-routing.module.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/frontend/src/app/app-routing.module.ts b/frontend/src/app/app-routing.module.ts
index 713fec384..42ae7cdd5 100644
--- a/frontend/src/app/app-routing.module.ts
+++ b/frontend/src/app/app-routing.module.ts
@@ -137,7 +137,7 @@ let routes: Routes = [
       },
       {
         path: 'docs',
-        redirectTo: 'docs/api/rest'
+        redirectTo: 'docs/faq'
       },
       {
         path: 'api',
@@ -284,7 +284,7 @@ let routes: Routes = [
           },
           {
             path: 'docs',
-            redirectTo: 'docs/api/rest'
+            redirectTo: 'docs/faq'
           },
           {
             path: 'api',
@@ -424,7 +424,7 @@ let routes: Routes = [
           },
           {
             path: 'docs',
-            redirectTo: 'docs/api/rest'
+            redirectTo: 'docs/faq'
           },
           {
             path: 'api',

From ef2c84571447e01a2a0dfd41c020bcd6710b0101 Mon Sep 17 00:00:00 2001
From: hunicus <93150691+hunicus@users.noreply.github.com>
Date: Sat, 26 Mar 2022 09:09:37 -0400
Subject: [PATCH 04/17] Generalize api-docs components to accommodate faq

Also add chunk of faq content.
---
 .../src/app/components/docs/api-docs-data.ts  | 174 ++++++++++++++++++
 .../docs/api-docs-nav.component.html          |   2 +-
 .../components/docs/api-docs-nav.component.ts |  10 +-
 .../components/docs/api-docs.component.html   |  30 ++-
 .../components/docs/api-docs.component.scss   |   8 +
 .../app/components/docs/api-docs.component.ts |   8 +-
 .../app/components/docs/docs.component.html   |   6 +-
 7 files changed, 225 insertions(+), 13 deletions(-)

diff --git a/frontend/src/app/components/docs/api-docs-data.ts b/frontend/src/app/components/docs/api-docs-data.ts
index 42fefcfe1..79df8bb25 100644
--- a/frontend/src/app/components/docs/api-docs-data.ts
+++ b/frontend/src/app/components/docs/api-docs-data.ts
@@ -4411,3 +4411,177 @@ export const restApiDocsData = [
   },
 ];
 
+export const faqData = [
+  {
+    type: "category",
+    category: "basics",
+    fragment: "basics",
+    title: "Basics",
+    showConditions: bitcoinNetworks
+  },
+  {
+    type: "endpoint",
+    category: "basics",
+    showConditions: bitcoinNetworks,
+    fragment: "what-is-a-mempool",
+    title: "What is a mempool?",
+    answer: '<p>A mempool (short for "memory pool") is a data structure that holds the queue of pending and unconfirmed transactions for a cryptocurrency network node. Every node on the network has its own mempool, which may contain different transactions.</p>'
+  },
+  {
+    type: "endpoint",
+    category: "basics",
+    showConditions: bitcoinNetworks,
+    fragment: "what-is-a-mempool-explorer",
+    title: "What is a mempool explorer?",
+    answer: '<p>A mempool explorer is a tool that enables you to explore a node’s mempool, by visualizing the transactions contained within it, and allowing you to search and view those pending transactions, as well as general information about the node’s mempool. </p><p>The mempool.space website invented the concept of visualizing a Bitcoin node’s mempool as <b>projected blocks</b>, which are visible on the left side of our main dashboard, and the inspiration for our half-filled block logo.</p>'
+  },
+  {
+    type: "endpoint",
+    category: "basics",
+    showConditions: bitcoinNetworks,
+    fragment: "what-is-a-blockchain",
+    title: "What is a blockchain?",
+    answer: "<p>A blockchain is the distributed ledger that records the transactions for a cryptocurrency network. Miners amend the blockchain ledger by mining new blocks.</p>"
+  },
+  {
+    type: "endpoint",
+    category: "basics",
+    showConditions: bitcoinNetworks,
+    fragment: "what-is-a-block-explorer",
+    title: "What is a block explorer?",
+    answer: "<p>A block explorer is a tool that enables you to explore the blockchain of a cryptocurrency  for real-time and historical information about a blockchain, including data related to blocks, transactions, addresses, and more.</p>"
+  },
+  {
+    type: "endpoint",
+    category: "basics",
+    showConditions: bitcoinNetworks,
+    fragment: "what-is-mining",
+    title: "What is mining?",
+    answer: "Because reasons."
+  },
+  {
+    type: "endpoint",
+    category: "basics",
+    showConditions: bitcoinNetworks,
+    fragment: "what-are-mining-pools",
+    title: "What are mining pools?",
+    answer: "Because reasons."
+  },
+  {
+    type: "category",
+    category: "help",
+    fragment: "help-stuck-transaction",
+    title: "Help! My transaction is stuck",
+    showConditions: bitcoinNetworks
+  },
+  {
+    type: "endpoint",
+    category: "help",
+    showConditions: bitcoinNetworks,
+    fragment: "why-is-transaction-stuck-in-the-mempool",
+    title: "Why is my transaction stuck in the mempool?",
+    answer: "<p>Miners decide which transactions get included into the blocks they mine, and so they usually prioritize the transactions which pay them the highest transaction fees, measured in sats per virtual byte. This means to get confirmed sooner, you need to pay a higher fee.</p>"
+  },
+  {
+    type: "endpoint",
+    category: "help",
+    showConditions: bitcoinNetworks,
+    fragment: "how-to-get-transaction-confirmed-quickly",
+    title: "How can I get my transaction confirmed quickly?",
+    answer: "<p>If your wallet supports RBF, and your transaction was created with RBF enabled, you can bump the fee higher.</p><p>If your wallet does not support RBF, you can increase the effective fee rate of your transaction by spending its change output using a higher fee. This is called CPFP.</p>"
+  },
+  {
+    type: "endpoint",
+    category: "help",
+    showConditions: bitcoinNetworks,
+    fragment: "how-prevent-stuck-transaction-in-future",
+    title: "How can I prevent a transaction from getting stuck in the future?",
+    answer: "<p>You must use an adequate fee rate. Also consider using RBF if your wallet supports it so that you can bump the fee rate if needed.</p>"
+  },
+  {
+    type: "category",
+    category: "using",
+    fragment: "using-this-website",
+    title: "Using this website",
+    showConditions: bitcoinNetworks
+  },
+  {
+    type: "endpoint",
+    category: "how-to",
+    showConditions: bitcoinNetworks,
+    fragment: "looking-up-transactions",
+    title: "How can I look up a transaction?",
+    answer: "Because reasons."
+  },
+  {
+    type: "endpoint",
+    category: "how-to",
+    showConditions: bitcoinNetworks,
+    fragment: "looking-up-addresses",
+    title: "How can I look up an address?",
+    answer: "Because reasons."
+  },
+  {
+    type: "endpoint",
+    category: "how-to",
+    showConditions: bitcoinNetworks,
+    fragment: "looking-up-blocks",
+    title: "How can I look up a block?",
+    answer: "Because reasons."
+  },
+  {
+    type: "endpoint",
+    category: "how-to",
+    showConditions: bitcoinNetworks,
+    fragment: "looking-up-fee-estimates",
+    title: "How can I look up fee estimates?",
+    answer: "Because reasons."
+  },
+  {
+    type: "endpoint",
+    category: "how-to",
+    showConditions: bitcoinNetworks,
+    fragment: "looking-up-historical-trends",
+    title: "How can I explore historical trends?",
+    answer: "Because reasons."
+  },
+  {
+    type: "category",
+    category: "advanced",
+    fragment: "advanced",
+    title: "Advanced",
+    showConditions: bitcoinNetworks
+  },
+  {
+    type: "endpoint",
+    category: "advanced",
+    showConditions: bitcoinNetworks,
+    fragment: "who-runs-this-website",
+    title: "Who runs this website?",
+    answer: "Because reasons."
+  },
+  {
+    type: "endpoint",
+    category: "advanced",
+    showConditions: bitcoinNetworks,
+    fragment: "host-my-own-instance-on-raspberry-pi",
+    title: "How can I host my own instance on a Raspberry Pi?",
+    answer: "Because reasons."
+  },
+  {
+    type: "endpoint",
+    category: "advanced",
+    showConditions: bitcoinNetworks,
+    fragment: "host-my-own-instance-on-linux-server",
+    title: "How can I host my own instance on a Linux server?",
+    answer: "Because reasons."
+  },
+  {
+    type: "endpoint",
+    category: "advanced",
+    showConditions: bitcoinNetworks,
+    fragment: "install-mempool-with-docker",
+    title: "Can I install Mempool using Docker?",
+    answer: "Because reasons."
+  }
+];
diff --git a/frontend/src/app/components/docs/api-docs-nav.component.html b/frontend/src/app/components/docs/api-docs-nav.component.html
index 83eaaf9e8..c8460ada4 100644
--- a/frontend/src/app/components/docs/api-docs-nav.component.html
+++ b/frontend/src/app/components/docs/api-docs-nav.component.html
@@ -1,4 +1,4 @@
-<div *ngFor="let item of restDocs">
+<div *ngFor="let item of tabData">
   <p *ngIf="( item.type === 'category' ) && ( item.showConditions.indexOf(network.val) > -1 )">{{ item.title }}</p>
   <a *ngIf="( item.type !== 'category' ) && ( item.showConditions.indexOf(network.val) > -1 )" [routerLink]="['./']" fragment="{{ item.fragment }}" (click)="navLinkClick($event)">{{ item.title }}</a>
 </div>
diff --git a/frontend/src/app/components/docs/api-docs-nav.component.ts b/frontend/src/app/components/docs/api-docs-nav.component.ts
index 90588860e..a7ec45569 100644
--- a/frontend/src/app/components/docs/api-docs-nav.component.ts
+++ b/frontend/src/app/components/docs/api-docs-nav.component.ts
@@ -1,5 +1,6 @@
 import { Component, OnInit, Input, Output, EventEmitter } from '@angular/core';
 import { restApiDocsData } from './api-docs-data';
+import { faqData } from './api-docs-data';
 
 @Component({
   selector: 'app-api-docs-nav',
@@ -9,13 +10,18 @@ import { restApiDocsData } from './api-docs-data';
 export class ApiDocsNavComponent implements OnInit {
 
   @Input() network: any;
+  @Input() whichTab: string;
   @Output() navLinkClickEvent: EventEmitter<any> = new EventEmitter();
-  restDocs: any[];
+  tabData: any[];
 
   constructor() { }
 
   ngOnInit(): void {
-    this.restDocs = restApiDocsData;
+    if( this.whichTab === 'rest' ) {
+      this.tabData = restApiDocsData;
+    } else if( this.whichTab = 'faq' ) {
+      this.tabData = faqData;
+    }
   }
   
   navLinkClick( event ) {
diff --git a/frontend/src/app/components/docs/api-docs.component.html b/frontend/src/app/components/docs/api-docs.component.html
index 88a48f975..e213d6a62 100644
--- a/frontend/src/app/components/docs/api-docs.component.html
+++ b/frontend/src/app/components/docs/api-docs.component.html
@@ -1,10 +1,32 @@
 <ng-container *ngIf="{ val: network$ | async } as network">
   <div class="container-xl text-left">
-
-    <div id="restAPI" *ngIf="restTabActivated">
+  
+    <div id="faq" *ngIf="whichTab === 'faq'">
 
       <div id="doc-nav-desktop" class="hide-on-mobile" [ngClass]="desktopDocsNavPosition">
-        <app-api-docs-nav (navLinkClickEvent)="anchorLinkClick( $event )" [network]="{ val: network$ | async }"></app-api-docs-nav>
+        <app-api-docs-nav (navLinkClickEvent)="anchorLinkClick( $event )" [network]="{ val: network$ | async }" [whichTab]="whichTab"></app-api-docs-nav>
+      </div>
+
+      <div class="doc-content">
+
+        <div *ngFor="let item of faq">
+          <h3 *ngIf="item.type === 'category'">{{ item.title }}</h3>
+          <div *ngIf="item.type !== 'category'" class="endpoint-container" id="{{ item.fragment }}">
+            <a class="section-header" (click)="anchorLinkClick( $event )" [routerLink]="['./']" fragment="{{ item.fragment }}"><table><tr><td>{{ item.title }}</td><td><span>{{ item.category }}</span></td></tr></table></a>
+            <div class="endpoint-content">
+              <div class="endpoint" [innerHTML]="item.answer"></div>
+            </div>
+          </div>
+        </div>
+        
+      </div>
+      
+    </div>
+
+    <div id="restAPI" *ngIf="whichTab === 'rest'">
+
+      <div id="doc-nav-desktop" class="hide-on-mobile" [ngClass]="desktopDocsNavPosition">
+        <app-api-docs-nav (navLinkClickEvent)="anchorLinkClick( $event )" [network]="{ val: network$ | async }" [whichTab]="whichTab"></app-api-docs-nav>
       </div>
 
       <div class="doc-content">
@@ -65,7 +87,7 @@
       </div>
     </div>
 
-    <div id="websocketAPI" *ngIf="!restTabActivated && ( network.val !== 'bisq' )">
+    <div id="websocketAPI" *ngIf="( whichTab === 'websocket' ) && ( network.val !== 'bisq' )">
       <div class="api-category">
         <div class="websocket">
           <div class="endpoint">
diff --git a/frontend/src/app/components/docs/api-docs.component.scss b/frontend/src/app/components/docs/api-docs.component.scss
index cb3770622..35ec9e423 100644
--- a/frontend/src/app/components/docs/api-docs.component.scss
+++ b/frontend/src/app/components/docs/api-docs.component.scss
@@ -152,6 +152,14 @@ h3 {
   float: right;
 }
 
+.endpoint-container .section-header table {
+  width: 100%;
+}
+
+.endpoint-container .section-header table td:first-child {
+  padding-right: 24px;
+}
+
 #doc-nav-mobile {
   position: fixed;
   top: 20px;
diff --git a/frontend/src/app/components/docs/api-docs.component.ts b/frontend/src/app/components/docs/api-docs.component.ts
index 5e2300fed..32ef12741 100644
--- a/frontend/src/app/components/docs/api-docs.component.ts
+++ b/frontend/src/app/components/docs/api-docs.component.ts
@@ -4,7 +4,7 @@ import { Observable, merge, of } from 'rxjs';
 import { SeoService } from 'src/app/services/seo.service';
 import { tap } from 'rxjs/operators';
 import { ActivatedRoute } from "@angular/router";
-import { restApiDocsData, wsApiDocsData } from './api-docs-data';
+import { faqData, restApiDocsData, wsApiDocsData } from './api-docs-data';
 
 @Component({
   selector: 'app-api-docs',
@@ -18,8 +18,9 @@ export class ApiDocsComponent implements OnInit {
   env: Env;
   code: any;
   baseNetworkUrl = '';
-  @Input() restTabActivated: Boolean;
+  @Input() whichTab: string;
   desktopDocsNavPosition = "relative";
+  faq: any[];
   restDocs: any[];
   wsDocs: any;
   screenWidth: number;
@@ -62,6 +63,7 @@ export class ApiDocsComponent implements OnInit {
 
     this.hostname = `${document.location.protocol}//${this.hostname}`;
 
+    this.faq = faqData;
     this.restDocs = restApiDocsData;
     this.wsDocs = wsApiDocsData;
 
@@ -79,7 +81,7 @@ export class ApiDocsComponent implements OnInit {
   }
 
   openEndpointContainer( targetId ) {
-    if( ( window.innerWidth <= 992 ) && this.restTabActivated && targetId ) {
+    if( ( window.innerWidth <= 992 ) && ( ( this.whichTab === 'rest' ) || ( this.whichTab === 'faq' ) ) && targetId ) {
       const endpointContainerEl = document.querySelector<HTMLElement>( "#" + targetId );
       const endpointContentEl = document.querySelector<HTMLElement>( "#" + targetId + " .endpoint-content" );
       const endPointContentElHeight = endpointContentEl.clientHeight;
diff --git a/frontend/src/app/components/docs/docs.component.html b/frontend/src/app/components/docs/docs.component.html
index 21d6ca93e..19a664e46 100644
--- a/frontend/src/app/components/docs/docs.component.html
+++ b/frontend/src/app/components/docs/docs.component.html
@@ -9,7 +9,7 @@
         <a ngbNavLink [routerLink]="['/docs/faq' | relativeUrl]">FAQ</a>
         <ng-template ngbNavContent>
 
-          <p>FAQ placeholder</p>
+          <app-api-docs [whichTab]="'faq'"></app-api-docs>
 
         </ng-template>
       </li>
@@ -18,7 +18,7 @@
         <a ngbNavLink [routerLink]="['/docs/api/rest' | relativeUrl]">API - REST</a>
         <ng-template ngbNavContent>
 
-          <app-api-docs [restTabActivated]="true"></app-api-docs>
+          <app-api-docs [whichTab]="'rest'"></app-api-docs>
 
         </ng-template>
       </li>
@@ -27,7 +27,7 @@
         <a ngbNavLink [routerLink]="['/docs/api/websocket' | relativeUrl]">API - WebSocket</a>
         <ng-template ngbNavContent>
 
-          <app-api-docs [restTabActivated]="false"></app-api-docs>
+          <app-api-docs [whichTab]="'websocket'"></app-api-docs>
 
         </ng-template>
       </li>

From c6c335921ccc382e505a456ed4d26bab77d56f7d Mon Sep 17 00:00:00 2001
From: hunicus <93150691+hunicus@users.noreply.github.com>
Date: Sat, 26 Mar 2022 23:31:49 -0400
Subject: [PATCH 05/17] Finish adding non-graphical faq content

---
 .../src/app/components/docs/api-docs-data.ts  | 28 +++++++++----------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/frontend/src/app/components/docs/api-docs-data.ts b/frontend/src/app/components/docs/api-docs-data.ts
index 79df8bb25..ed4703641 100644
--- a/frontend/src/app/components/docs/api-docs-data.ts
+++ b/frontend/src/app/components/docs/api-docs-data.ts
@@ -4425,7 +4425,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "what-is-a-mempool",
     title: "What is a mempool?",
-    answer: '<p>A mempool (short for "memory pool") is a data structure that holds the queue of pending and unconfirmed transactions for a cryptocurrency network node. Every node on the network has its own mempool, which may contain different transactions.</p>'
+    answer: "<p>A mempool (short for \"memory pool\") holds the queue of pending and unconfirmed transactions for a cryptocurrency network node. There is no one global mempool: every node on the network maintains its own mempool, so different nodes may hold different transactions in their mempools.</p>"
   },
   {
     type: "endpoint",
@@ -4433,7 +4433,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "what-is-a-mempool-explorer",
     title: "What is a mempool explorer?",
-    answer: '<p>A mempool explorer is a tool that enables you to explore a node’s mempool, by visualizing the transactions contained within it, and allowing you to search and view those pending transactions, as well as general information about the node’s mempool. </p><p>The mempool.space website invented the concept of visualizing a Bitcoin node’s mempool as <b>projected blocks</b>, which are visible on the left side of our main dashboard, and the inspiration for our half-filled block logo.</p>'
+    answer: "<p>A mempool explorer is a tool that enables you to explore a node's mempool by visualizing its transactions, searching and viewing those transactions, and viewing aggregate and historical data about a node's mempool. </p><p>The mempool.space website invented the concept of visualizing a Bitcoin node's mempool as <b>projected blocks</b>. These blocks are the inspiration for our half-filled block logo.</p><p>Here's a snapshot of this visualization (which you can find on <a href='/'>the main dashboard</a>) as of block 729,131 in March 2022. Projected blocks are on the left, and confirmed blocks are on the right.</p>"
   },
   {
     type: "endpoint",
@@ -4441,7 +4441,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "what-is-a-blockchain",
     title: "What is a blockchain?",
-    answer: "<p>A blockchain is the distributed ledger that records the transactions for a cryptocurrency network. Miners amend the blockchain ledger by mining new blocks.</p>"
+    answer: "<p>A blockchain is a distributed ledger that records the transactions for a cryptocurrency network. Miners amend the blockchain ledger by mining new blocks.</p>"
   },
   {
     type: "endpoint",
@@ -4449,7 +4449,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "what-is-a-block-explorer",
     title: "What is a block explorer?",
-    answer: "<p>A block explorer is a tool that enables you to explore the blockchain of a cryptocurrency  for real-time and historical information about a blockchain, including data related to blocks, transactions, addresses, and more.</p>"
+    answer: "<p>A block explorer is a tool that enables you to explore real-time and historical information about the blockchain of a cryptocurrency. This includes data related to blocks, transactions, addresses, and more.</p>"
   },
   {
     type: "endpoint",
@@ -4457,7 +4457,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "what-is-mining",
     title: "What is mining?",
-    answer: "Because reasons."
+    answer: "Mining is the process by which unconfirmed transactions are confirmed. Miners select unconfirmed transactions from their mempools and arrange them into a block such that they solve a particular math problem.</p><p>The first miner on the network that finds a suitable block gets all the transaction fees from the transactions in that block. As a result, miners tend to prioritize transactions with higher transaction fees.</p>"
   },
   {
     type: "endpoint",
@@ -4465,7 +4465,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "what-are-mining-pools",
     title: "What are mining pools?",
-    answer: "Because reasons."
+    answer: "Mining pools are groups of miners that combine their computational power in order to increase the probability of finding new blocks."
   },
   {
     type: "category",
@@ -4480,15 +4480,15 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "why-is-transaction-stuck-in-the-mempool",
     title: "Why is my transaction stuck in the mempool?",
-    answer: "<p>Miners decide which transactions get included into the blocks they mine, and so they usually prioritize the transactions which pay them the highest transaction fees, measured in sats per virtual byte. This means to get confirmed sooner, you need to pay a higher fee.</p>"
+    answer: "<p>Miners decide which transactions are included in the blocks they mine, so they usually prioritize transactions which pay them the highest transaction fees (transaction fees are measured in sats per virtual byte, or sat/vB). If your transcation is stuck in the mempool, your transaction probably has a lower transaction fee relative to other transactions currently in the mempool.</p>"
   },
   {
     type: "endpoint",
     category: "help",
     showConditions: bitcoinNetworks,
     fragment: "how-to-get-transaction-confirmed-quickly",
-    title: "How can I get my transaction confirmed quickly?",
-    answer: "<p>If your wallet supports RBF, and your transaction was created with RBF enabled, you can bump the fee higher.</p><p>If your wallet does not support RBF, you can increase the effective fee rate of your transaction by spending its change output using a higher fee. This is called CPFP.</p>"
+    title: "How can I get my transaction confirmed more quickly?",
+    answer: "<p>If your wallet supports RBF, and if your transaction was created with RBF enabled, you can bump the fee higher.</p><p>Otherwise, if your wallet does not support RBF, you can increase the effective fee rate of your transaction by spending its change output using a higher fee. This is called CPFP.</p>"
   },
   {
     type: "endpoint",
@@ -4496,7 +4496,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "how-prevent-stuck-transaction-in-future",
     title: "How can I prevent a transaction from getting stuck in the future?",
-    answer: "<p>You must use an adequate fee rate. Also consider using RBF if your wallet supports it so that you can bump the fee rate if needed.</p>"
+    answer: "<p>You must use an adequate transaction fee commensurate with how quickly you need the transaction to be confirmed. Also consider using RBF if your wallet supports it so that you can bump the fee rate if needed.</p>"
   },
   {
     type: "category",
@@ -4558,7 +4558,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "who-runs-this-website",
     title: "Who runs this website?",
-    answer: "Because reasons."
+    answer: "The official mempool.space website is operated by The Mempool Open Source Project. See more information <a href='/about'>on our About page</a>. There are also many unofficial instances of this website operated by individual members of the Bitcoin community."
   },
   {
     type: "endpoint",
@@ -4566,7 +4566,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "host-my-own-instance-on-raspberry-pi",
     title: "How can I host my own instance on a Raspberry Pi?",
-    answer: "Because reasons."
+    answer: "We support one-click installation on a number of Raspberry Pi fullnode distros including Umbrel, RaspiBlitz, MyNode, and RoninDojo."
   },
   {
     type: "endpoint",
@@ -4574,7 +4574,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "host-my-own-instance-on-linux-server",
     title: "How can I host my own instance on a Linux server?",
-    answer: "Because reasons."
+    answer: "You can manually install mempool on your own Linux server, but this requires advanced sysadmin skills since you will be manually configuring everything. We do not provide support for manual deployments."
   },
   {
     type: "endpoint",
@@ -4582,6 +4582,6 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "install-mempool-with-docker",
     title: "Can I install Mempool using Docker?",
-    answer: "Because reasons."
+    answer: "Yes, we publish Docker images (or you can build your own), and provide <a href='https://github.com/mempool/mempool/tree/master/docker' target='_blank'>an example docker-compose template</a>."
   }
 ];

From 663cf100d17d29175077999549083a641dac65f4 Mon Sep 17 00:00:00 2001
From: hunicus <93150691+hunicus@users.noreply.github.com>
Date: Sun, 27 Mar 2022 01:19:48 -0400
Subject: [PATCH 06/17] Add no-sanitize pipe

---
 frontend/src/app/app.module.ts                    |  2 ++
 frontend/src/app/shared/pipes/no-sanitize.pipe.ts | 11 +++++++++++
 2 files changed, 13 insertions(+)
 create mode 100644 frontend/src/app/shared/pipes/no-sanitize.pipe.ts

diff --git a/frontend/src/app/app.module.ts b/frontend/src/app/app.module.ts
index 807c88ade..007763305 100644
--- a/frontend/src/app/app.module.ts
+++ b/frontend/src/app/app.module.ts
@@ -56,6 +56,7 @@ import { faFilter, faAngleDown, faAngleUp, faAngleRight, faAngleLeft, faBolt, fa
 import { ApiDocsComponent } from './components/docs/api-docs.component';
 import { DocsComponent } from './components/docs/docs.component';
 import { ApiDocsNavComponent } from './components/docs/api-docs-nav.component';
+import { NoSanitizePipe } from './shared/pipes/no-sanitize.pipe';
 import { CodeTemplateComponent } from './components/docs/code-template.component';
 import { TermsOfServiceComponent } from './components/terms-of-service/terms-of-service.component';
 import { PrivacyPolicyComponent } from './components/privacy-policy/privacy-policy.component';
@@ -119,6 +120,7 @@ import { DataCyDirective } from './data-cy.directive';
     DashboardComponent,
     DifficultyComponent,
     ApiDocsComponent,
+    NoSanitizePipe,
     CodeTemplateComponent,
     TermsOfServiceComponent,
     PrivacyPolicyComponent,
diff --git a/frontend/src/app/shared/pipes/no-sanitize.pipe.ts b/frontend/src/app/shared/pipes/no-sanitize.pipe.ts
new file mode 100644
index 000000000..039eafb76
--- /dev/null
+++ b/frontend/src/app/shared/pipes/no-sanitize.pipe.ts
@@ -0,0 +1,11 @@
+import { Pipe, PipeTransform } from '@angular/core';
+import { DomSanitizer, SafeHtml } from '@angular/platform-browser';
+
+@Pipe({ name: 'noSanitize' })
+export class NoSanitizePipe implements PipeTransform {
+  constructor(private domSanitizer: DomSanitizer) { }
+
+  transform(html: string): SafeHtml {
+    return this.domSanitizer.bypassSecurityTrustHtml(html);
+  }
+}

From 918798aca3200b5660f2a99dcb6ee6b6f6f42b42 Mon Sep 17 00:00:00 2001
From: wiz <j@wiz.biz>
Date: Sat, 2 Apr 2022 10:14:22 -0400
Subject: [PATCH 07/17] Fix newsyslog configuration for mempool backend

---
 production/newsyslog-mempool-backend.conf | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/production/newsyslog-mempool-backend.conf b/production/newsyslog-mempool-backend.conf
index 8a3aab320..5c96da47a 100644
--- a/production/newsyslog-mempool-backend.conf
+++ b/production/newsyslog-mempool-backend.conf
@@ -1,2 +1,2 @@
-/var/log/mempool			640  10	   *	168   J
-/var/log/mempool.debug			640  10	   1000	*     J
+/var/log/mempool			640  10	   *	@T00	C
+/var/log/mempool.debug			640  10	   *	@T00	C

From dfb5ba5c3609905277956364ad081a40a46d3d04 Mon Sep 17 00:00:00 2001
From: Antoni Spaanderman <56turtle56@gmail.com>
Date: Sun, 3 Apr 2022 21:41:12 +0200
Subject: [PATCH 08/17] Completely rewrote convertScriptSigAsm

it now gives identical output to esplora, tested with the following TXs (testnet):

88710a9a6751827490f260e307757543f533c0f18bcd6865794713d263d5f5a4
446b2aad074de94efa28a1e82d2e6016dcb8a8ca38aca1a5a8eac6ef54e56a2e
4cfc410092e9514c14f48b61e20d2d3baf540ae7e981a821dd8c05dd4b7cd591
4b55dde38173174ab09e5571ebffffca798ba11143d28b9770600ff376dc778a
---
 backend/src/api/bitcoin/bitcoin-api.ts | 85 ++++++++++++++++----------
 1 file changed, 54 insertions(+), 31 deletions(-)

diff --git a/backend/src/api/bitcoin/bitcoin-api.ts b/backend/src/api/bitcoin/bitcoin-api.ts
index 061b3ced1..ec786593e 100644
--- a/backend/src/api/bitcoin/bitcoin-api.ts
+++ b/backend/src/api/bitcoin/bitcoin-api.ts
@@ -147,7 +147,7 @@ class BitcoinApi implements AbstractBitcoinApi {
         scriptpubkey: vout.scriptPubKey.hex,
         scriptpubkey_address: vout.scriptPubKey && vout.scriptPubKey.address ? vout.scriptPubKey.address
           : vout.scriptPubKey.addresses ? vout.scriptPubKey.addresses[0] : '',
-        scriptpubkey_asm: vout.scriptPubKey.asm ? this.convertScriptSigAsm(vout.scriptPubKey.asm) : '',
+        scriptpubkey_asm: vout.scriptPubKey.asm ? this.convertScriptSigAsm(vout.scriptPubKey.hex) : '',
         scriptpubkey_type: this.translateScriptPubKeyType(vout.scriptPubKey.type),
       };
     });
@@ -157,7 +157,7 @@ class BitcoinApi implements AbstractBitcoinApi {
         is_coinbase: !!vin.coinbase,
         prevout: null,
         scriptsig: vin.scriptSig && vin.scriptSig.hex || vin.coinbase || '',
-        scriptsig_asm: vin.scriptSig && this.convertScriptSigAsm(vin.scriptSig.asm) || '',
+        scriptsig_asm: vin.scriptSig && this.convertScriptSigAsm(vin.scriptSig.hex) || '',
         sequence: vin.sequence,
         txid: vin.txid || '',
         vout: vin.vout || 0,
@@ -290,38 +290,61 @@ class BitcoinApi implements AbstractBitcoinApi {
     return transaction;
   }
 
-  private convertScriptSigAsm(str: string): string {
-    const a = str.split(' ');
+  private convertScriptSigAsm(hex: string): string {
+    const buf = Buffer.from(hex, 'hex');
+
     const b: string[] = [];
-    a.forEach((chunk) => {
-      if (chunk.substr(0, 3) === 'OP_') {
-        chunk = chunk.replace(/^OP_(\d+)$/, 'OP_PUSHNUM_$1');
-        chunk = chunk.replace('OP_CHECKSEQUENCEVERIFY', 'OP_CSV');
-        chunk = chunk.replace('OP_CHECKLOCKTIMEVERIFY', 'OP_CLTV');
-        b.push(chunk);
+
+    let i = 0;
+    while (i < buf.length) {
+      const op = buf[i];
+      if (op >= 0x01 && op <= 0x4e) {
+        i++;
+        let push: number;
+        if (op === 0x4c) {
+          push = buf.readUInt8(i);
+          b.push('OP_PUSHDATA1');
+          i += 1;
+        } else if (op === 0x4d) {
+          push = buf.readUInt16LE(i);
+          b.push('OP_PUSHDATA2');
+          i += 2;
+        } else if (op === 0x4e) {
+          push = buf.readUInt32LE(i);
+          b.push('OP_PUSHDATA4');
+          i += 4;
+        } else {
+          push = op;
+          b.push('OP_PUSHBYTES_' + push);
+        }
+
+        const data = buf.slice(i, i + push);
+        if (data.length !== push) {
+          break;
+        }
+
+        b.push(data.toString('hex'));
+        i += data.length;
       } else {
-        chunk = chunk.replace('[ALL]', '01');
-        if (chunk === '0') {
-          b.push('OP_0');
-        } else if (chunk.match(/^[^0]\d*$/)) {
-          const chunkInt = parseInt(chunk, 10);
-          if (chunkInt < 0) {
-            b.push('OP_PUSHNUM_NEG' + -chunkInt);
+        const opcode = bitcoinjs.script.toASM([ op ]);
+        if (opcode && op < 0xfd) {
+          if (opcode === 'OP_1NEGATE') {
+            b.push('OP_PUSHNUM_NEG1');
+          } else if (/^OP_(\d+)$/.test(opcode) && opcode !== 'OP_0') {
+            b.push(opcode.replace(/^OP_(\d+)$/, 'OP_PUSHNUM_$1'));
           } else {
-            b.push('OP_PUSHNUM_' + chunk);
+            b.push(opcode
+              .replace('OP_CHECKSEQUENCEVERIFY', 'OP_CSV')
+              .replace('OP_CHECKLOCKTIMEVERIFY', 'OP_CLTV')
+            );
           }
         } else {
-          const dataLength = Math.round(chunk.length / 2);
-          if (dataLength > 255) {
-            b.push('OP_PUSHDATA2' + ' ' + chunk);
-          } else if (dataLength > 75) {
-            b.push('OP_PUSHDATA1' + ' ' + chunk);
-          } else {
-            b.push('OP_PUSHBYTES_' + dataLength + ' ' + chunk);
-          }
+          b.push('OP_RETURN_' + op);
         }
+        i += 1;
       }
-    });
+    }
+
     return b.join(' ');
   }
 
@@ -332,21 +355,21 @@ class BitcoinApi implements AbstractBitcoinApi {
 
     if (vin.prevout.scriptpubkey_type === 'p2sh') {
       const redeemScript = vin.scriptsig_asm.split(' ').reverse()[0];
-      vin.inner_redeemscript_asm = this.convertScriptSigAsm(bitcoinjs.script.toASM(Buffer.from(redeemScript, 'hex')));
+      vin.inner_redeemscript_asm = this.convertScriptSigAsm(redeemScript);
       if (vin.witness && vin.witness.length > 2) {
         const witnessScript = vin.witness[vin.witness.length - 1];
-        vin.inner_witnessscript_asm = this.convertScriptSigAsm(bitcoinjs.script.toASM(Buffer.from(witnessScript, 'hex')));
+        vin.inner_witnessscript_asm = this.convertScriptSigAsm(witnessScript);
       }
     }
 
     if (vin.prevout.scriptpubkey_type === 'v0_p2wsh' && vin.witness) {
       const witnessScript = vin.witness[vin.witness.length - 1];
-      vin.inner_witnessscript_asm = this.convertScriptSigAsm(bitcoinjs.script.toASM(Buffer.from(witnessScript, 'hex')));
+      vin.inner_witnessscript_asm = this.convertScriptSigAsm(witnessScript);
     }
 
     if (vin.prevout.scriptpubkey_type === 'v1_p2tr' && vin.witness && vin.witness.length > 1) {
       const witnessScript = vin.witness[vin.witness.length - 2];
-      vin.inner_witnessscript_asm = this.convertScriptSigAsm(bitcoinjs.script.toASM(Buffer.from(witnessScript, 'hex')));
+      vin.inner_witnessscript_asm = this.convertScriptSigAsm(witnessScript);
     }
   }
 

From 096f2172c6a93473ce55e94f93368f281db4ad5e Mon Sep 17 00:00:00 2001
From: Antoni Spaanderman <56turtle56@gmail.com>
Date: Sun, 3 Apr 2022 21:58:53 +0200
Subject: [PATCH 09/17] more direct opcode comparison

---
 backend/src/api/bitcoin/bitcoin-api.ts | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/backend/src/api/bitcoin/bitcoin-api.ts b/backend/src/api/bitcoin/bitcoin-api.ts
index ec786593e..17808d8bc 100644
--- a/backend/src/api/bitcoin/bitcoin-api.ts
+++ b/backend/src/api/bitcoin/bitcoin-api.ts
@@ -328,15 +328,16 @@ class BitcoinApi implements AbstractBitcoinApi {
       } else {
         const opcode = bitcoinjs.script.toASM([ op ]);
         if (opcode && op < 0xfd) {
-          if (opcode === 'OP_1NEGATE') {
+          if (op === 0x4f) {
             b.push('OP_PUSHNUM_NEG1');
-          } else if (/^OP_(\d+)$/.test(opcode) && opcode !== 'OP_0') {
+          } else if (/^OP_(\d+)$/.test(opcode) && op !== 0x00) {
             b.push(opcode.replace(/^OP_(\d+)$/, 'OP_PUSHNUM_$1'));
+          } else if (op === 0xb1) {
+            b.push('OP_CLTV');
+          } else if (op === 0xb2) {
+            b.push('OP_CSV');
           } else {
-            b.push(opcode
-              .replace('OP_CHECKSEQUENCEVERIFY', 'OP_CSV')
-              .replace('OP_CHECKLOCKTIMEVERIFY', 'OP_CLTV')
-            );
+            b.push(opcode);
           }
         } else {
           b.push('OP_RETURN_' + op);

From 53d68a3571e09fa777b651a03eb476b01d71b06e Mon Sep 17 00:00:00 2001
From: Antoni Spaanderman <56turtle56@gmail.com>
Date: Mon, 4 Apr 2022 17:16:34 +0200
Subject: [PATCH 10/17] name tapscript by its name + OP_CHECKSIGADD tapscript
 opcode detection

---
 backend/src/api/bitcoin/bitcoin-api.ts        | 34 +++++++++++--------
 .../transactions-list.component.html          |  5 ++-
 .../pipes/asm-styler/asm-styler.pipe.ts       |  1 +
 3 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/backend/src/api/bitcoin/bitcoin-api.ts b/backend/src/api/bitcoin/bitcoin-api.ts
index 17808d8bc..7b1fc161d 100644
--- a/backend/src/api/bitcoin/bitcoin-api.ts
+++ b/backend/src/api/bitcoin/bitcoin-api.ts
@@ -326,21 +326,27 @@ class BitcoinApi implements AbstractBitcoinApi {
         b.push(data.toString('hex'));
         i += data.length;
       } else {
-        const opcode = bitcoinjs.script.toASM([ op ]);
-        if (opcode && op < 0xfd) {
-          if (op === 0x4f) {
-            b.push('OP_PUSHNUM_NEG1');
-          } else if (/^OP_(\d+)$/.test(opcode) && op !== 0x00) {
-            b.push(opcode.replace(/^OP_(\d+)$/, 'OP_PUSHNUM_$1'));
-          } else if (op === 0xb1) {
-            b.push('OP_CLTV');
-          } else if (op === 0xb2) {
-            b.push('OP_CSV');
-          } else {
-            b.push(opcode);
-          }
+        if (op === 0x00) {
+          b.push('OP_0');
+        } else if (op === 0x4f) {
+          b.push('OP_PUSHNUM_NEG1');
+        } else if (op === 0xb1) {
+          b.push('OP_CLTV');
+        } else if (op === 0xb2) {
+          b.push('OP_CSV');
+        } else if (op === 0xba) {
+          b.push('OP_CHECKSIGADD');
         } else {
-          b.push('OP_RETURN_' + op);
+          const opcode = bitcoinjs.script.toASM([ op ]);
+          if (opcode && op < 0xfd) {
+            if (/^OP_(\d+)$/.test(opcode)) {
+              b.push(opcode.replace(/^OP_(\d+)$/, 'OP_PUSHNUM_$1'));
+            } else {
+              b.push(opcode);
+            }
+          } else {
+            b.push('OP_RETURN_' + op);
+          }
         }
         i += 1;
       }
diff --git a/frontend/src/app/components/transactions-list/transactions-list.component.html b/frontend/src/app/components/transactions-list/transactions-list.component.html
index 72407a405..eded208bd 100644
--- a/frontend/src/app/components/transactions-list/transactions-list.component.html
+++ b/frontend/src/app/components/transactions-list/transactions-list.component.html
@@ -111,7 +111,10 @@
                         <td style="text-align: left;" [innerHTML]="vin.inner_redeemscript_asm | asmStyler"></td>
                       </tr>
                       <tr *ngIf="vin.inner_witnessscript_asm">
-                        <td i18n="transactions-list.p2wsh-witness-script">P2WSH witness script</td>
+                        <td *ngIf="vin.prevout && vin.prevout.scriptpubkey_type == 'v1_p2tr'; else p2wsh" i18n="transactions-list.p2tr-tapscript">P2TR tapscript</td>
+                        <ng-template #p2wsh>
+                          <td i18n="transactions-list.p2wsh-witness-script">P2WSH witness script</td>
+                        </ng-template>
                         <td style="text-align: left;" [innerHTML]="vin.inner_witnessscript_asm | asmStyler"></td>
                       </tr>
                       <tr>
diff --git a/frontend/src/app/shared/pipes/asm-styler/asm-styler.pipe.ts b/frontend/src/app/shared/pipes/asm-styler/asm-styler.pipe.ts
index f6f1a59ad..54a02e405 100644
--- a/frontend/src/app/shared/pipes/asm-styler/asm-styler.pipe.ts
+++ b/frontend/src/app/shared/pipes/asm-styler/asm-styler.pipe.ts
@@ -281,6 +281,7 @@ export class AsmStylerPipe implements PipeTransform {
       case 'CHECKSIGVERIFY':
       case 'CHECKMULTISIG':
       case 'CHECKMULTISIGVERIFY':
+      case 'CHECKSIGADD':
         style = 'crypto';
         break;
 

From 039e6bbe7785a372619ecbb26c650244e916ffb2 Mon Sep 17 00:00:00 2001
From: hunicus <93150691+hunicus@users.noreply.github.com>
Date: Tue, 12 Apr 2022 15:31:45 -0400
Subject: [PATCH 11/17] Add answers, fix accordions, tweak footer styling

Main purpose of this commit is to remove iframes from git
history. This commit squashes several commits that came
after iframes were added.
---
 .../src/app/components/docs/api-docs-data.ts  | 28 +++++++++----------
 .../components/docs/api-docs.component.html   | 10 +++----
 .../components/docs/api-docs.component.scss   |  4 +++
 .../app/components/docs/api-docs.component.ts | 20 ++++++++++---
 4 files changed, 39 insertions(+), 23 deletions(-)

diff --git a/frontend/src/app/components/docs/api-docs-data.ts b/frontend/src/app/components/docs/api-docs-data.ts
index ed4703641..a369ac63b 100644
--- a/frontend/src/app/components/docs/api-docs-data.ts
+++ b/frontend/src/app/components/docs/api-docs-data.ts
@@ -4433,7 +4433,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "what-is-a-mempool-explorer",
     title: "What is a mempool explorer?",
-    answer: "<p>A mempool explorer is a tool that enables you to explore a node's mempool by visualizing its transactions, searching and viewing those transactions, and viewing aggregate and historical data about a node's mempool. </p><p>The mempool.space website invented the concept of visualizing a Bitcoin node's mempool as <b>projected blocks</b>. These blocks are the inspiration for our half-filled block logo.</p><p>Here's a snapshot of this visualization (which you can find on <a href='/'>the main dashboard</a>) as of block 729,131 in March 2022. Projected blocks are on the left, and confirmed blocks are on the right.</p>"
+    answer: "<p>A mempool explorer is a tool that enables you to view real-time and historical information about a node's mempool, visualize its transactions, and search and view those transactions.</p><p>The mempool.space website invented the concept of visualizing a Bitcoin node's mempool as <b>projected blocks</b>. These blocks are the inspiration for our half-filled block logo.</p><p>Here's a snapshot of this visualization (which you can find on <a href='/'>the main dashboard</a>) as of block 729,556 in March 2022. Projected blocks are on the left of the dotted white line, and confirmed blocks are on the right.</p><iframe id='mempool-blocks' style='width: 100%;height: 275px;border: none' src='./resources/mempool-blocks.html' scrolling='no'></iframe>"
   },
   {
     type: "endpoint",
@@ -4457,7 +4457,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "what-is-mining",
     title: "What is mining?",
-    answer: "Mining is the process by which unconfirmed transactions are confirmed. Miners select unconfirmed transactions from their mempools and arrange them into a block such that they solve a particular math problem.</p><p>The first miner on the network that finds a suitable block gets all the transaction fees from the transactions in that block. As a result, miners tend to prioritize transactions with higher transaction fees.</p>"
+    answer: "Mining is the process by which unconfirmed transactions in a mempool are confirmed into a block on a blockchain. Miners select unconfirmed transactions from their mempools and arrange them into a block such that they solve a particular math problem.</p><p>The first miner on the network to find a suitable block earns all the transaction fees from the transactions in that block. As a result, miners tend to prioritize transactions with higher transaction fees.</p>"
   },
   {
     type: "endpoint",
@@ -4478,9 +4478,9 @@ export const faqData = [
     type: "endpoint",
     category: "help",
     showConditions: bitcoinNetworks,
-    fragment: "why-is-transaction-stuck-in-the-mempool",
+    fragment: "why-is-transaction-stuck-in-mempool",
     title: "Why is my transaction stuck in the mempool?",
-    answer: "<p>Miners decide which transactions are included in the blocks they mine, so they usually prioritize transactions which pay them the highest transaction fees (transaction fees are measured in sats per virtual byte, or sat/vB). If your transcation is stuck in the mempool, your transaction probably has a lower transaction fee relative to other transactions currently in the mempool.</p>"
+    answer: "<p>Miners decide which transactions are included in the blocks they mine, so they usually prioritize transactions which pay them the highest transaction fees (transaction fees are measured in sats per virtual byte, or sat/vB). If it's been a while and your transcation hasn't been confirmed, your transaction probably has a lower transaction fee relative to other transactions currently in the mempool.</p>"
   },
   {
     type: "endpoint",
@@ -4494,7 +4494,7 @@ export const faqData = [
     type: "endpoint",
     category: "help",
     showConditions: bitcoinNetworks,
-    fragment: "how-prevent-stuck-transaction-in-future",
+    fragment: "how-prevent-stuck-transaction",
     title: "How can I prevent a transaction from getting stuck in the future?",
     answer: "<p>You must use an adequate transaction fee commensurate with how quickly you need the transaction to be confirmed. Also consider using RBF if your wallet supports it so that you can bump the fee rate if needed.</p>"
   },
@@ -4511,7 +4511,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "looking-up-transactions",
     title: "How can I look up a transaction?",
-    answer: "Because reasons."
+    answer: "Search for the transaction ID in the search box at the top-right of this website."
   },
   {
     type: "endpoint",
@@ -4519,7 +4519,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "looking-up-addresses",
     title: "How can I look up an address?",
-    answer: "Because reasons."
+    answer: "Search for the address in the search box at the top-right of this website."
   },
   {
     type: "endpoint",
@@ -4527,7 +4527,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "looking-up-blocks",
     title: "How can I look up a block?",
-    answer: "Because reasons."
+    answer: "Search for the block number (or block hash) in the search box at the top-right of this website."
   },
   {
     type: "endpoint",
@@ -4535,7 +4535,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "looking-up-fee-estimates",
     title: "How can I look up fee estimates?",
-    answer: "Because reasons."
+    answer: "<p>See real-time fee estimates on <a href='/'>the main dashboard</a>.</p><p>Low priority is suggested for confirmation within 6 blocks (~1 hour), Medium priority is suggested for confirmation within 3 blocks (~30 minutes), and High priority is suggested for confirmation in the next block (~10 minutes).</p>"
   },
   {
     type: "endpoint",
@@ -4543,7 +4543,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "looking-up-historical-trends",
     title: "How can I explore historical trends?",
-    answer: "Because reasons."
+    answer: "See the <a href='/graphs'>graphs page</a> for aggregate trends over time: mempool size over time and incoming transaction velocity over time."
   },
   {
     type: "category",
@@ -4558,21 +4558,21 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "who-runs-this-website",
     title: "Who runs this website?",
-    answer: "The official mempool.space website is operated by The Mempool Open Source Project. See more information <a href='/about'>on our About page</a>. There are also many unofficial instances of this website operated by individual members of the Bitcoin community."
+    answer: "The official mempool.space website is operated by The Mempool Open Source Project. See more information on our <a href='/about'>About page</a>. There are also many unofficial instances of this website operated by individual members of the Bitcoin community."
   },
   {
     type: "endpoint",
     category: "advanced",
     showConditions: bitcoinNetworks,
-    fragment: "host-my-own-instance-on-raspberry-pi",
+    fragment: "host-my-own-instance-raspberry-pi",
     title: "How can I host my own instance on a Raspberry Pi?",
-    answer: "We support one-click installation on a number of Raspberry Pi fullnode distros including Umbrel, RaspiBlitz, MyNode, and RoninDojo."
+    answer: "We support one-click installation on a number of Raspberry Pi full-node distros including Umbrel, RaspiBlitz, MyNode, and RoninDojo."
   },
   {
     type: "endpoint",
     category: "advanced",
     showConditions: bitcoinNetworks,
-    fragment: "host-my-own-instance-on-linux-server",
+    fragment: "host-my-own-instance-linux-server",
     title: "How can I host my own instance on a Linux server?",
     answer: "You can manually install mempool on your own Linux server, but this requires advanced sysadmin skills since you will be manually configuring everything. We do not provide support for manual deployments."
   },
diff --git a/frontend/src/app/components/docs/api-docs.component.html b/frontend/src/app/components/docs/api-docs.component.html
index e213d6a62..f33c777c9 100644
--- a/frontend/src/app/components/docs/api-docs.component.html
+++ b/frontend/src/app/components/docs/api-docs.component.html
@@ -9,12 +9,12 @@
 
       <div class="doc-content">
 
-        <div *ngFor="let item of faq">
+        <div class="doc-item-container" *ngFor="let item of faq">
           <h3 *ngIf="item.type === 'category'">{{ item.title }}</h3>
           <div *ngIf="item.type !== 'category'" class="endpoint-container" id="{{ item.fragment }}">
-            <a class="section-header" (click)="anchorLinkClick( $event )" [routerLink]="['./']" fragment="{{ item.fragment }}"><table><tr><td>{{ item.title }}</td><td><span>{{ item.category }}</span></td></tr></table></a>
+            <a id="{{ item.fragment + '-tab-header' }}" class="section-header" (click)="anchorLinkClick( $event )" [routerLink]="['./']" fragment="{{ item.fragment }}"><table><tr><td>{{ item.title }}</td><td><span>{{ item.category }}</span></td></tr></table></a>
             <div class="endpoint-content">
-              <div class="endpoint" [innerHTML]="item.answer"></div>
+              <div class="endpoint" [innerHTML]="item.answer | noSanitize"></div>
             </div>
           </div>
         </div>
@@ -33,10 +33,10 @@
 
         <p class="hide-on-mobile no-bottom-space">Reference for the {{ network.val === '' ? 'Bitcoin' : network.val.charAt(0).toUpperCase() + network.val.slice(1) }} <ng-container i18n="api-docs.title">API service</ng-container>.</p>
 
-        <div *ngFor="let item of restDocs">
+        <div class="doc-item-container" *ngFor="let item of restDocs">
           <h3 *ngIf="( item.type === 'category' ) && ( item.showConditions.indexOf(network.val) > -1 )">{{ item.title }}</h3>
           <div *ngIf="( item.type !== 'category' ) && ( item.showConditions.indexOf(network.val) > -1 )" class="endpoint-container" id="{{ item.fragment }}">
-            <a class="section-header" (click)="anchorLinkClick( $event )" [routerLink]="['./']" fragment="{{ item.fragment }}">{{ item.title }} <span>{{ item.category }}</span></a>
+            <a id="{{ item.fragment + '-tab-header' }}" class="section-header" (click)="anchorLinkClick( $event )" [routerLink]="['./']" fragment="{{ item.fragment }}">{{ item.title }} <span>{{ item.category }}</span></a>
             <div class="endpoint-content">
               <div class="endpoint">
                 <div class="subtitle" i18n="Api docs endpoint">Endpoint</div>
diff --git a/frontend/src/app/components/docs/api-docs.component.scss b/frontend/src/app/components/docs/api-docs.component.scss
index 35ec9e423..ce74cd951 100644
--- a/frontend/src/app/components/docs/api-docs.component.scss
+++ b/frontend/src/app/components/docs/api-docs.component.scss
@@ -239,4 +239,8 @@ h3 {
   h3 {
     display: none;
   }
+  
+  .doc-item-container:last-of-type .endpoint-container {
+    margin-bottom: 4rem;
+  }
 }
diff --git a/frontend/src/app/components/docs/api-docs.component.ts b/frontend/src/app/components/docs/api-docs.component.ts
index 32ef12741..39f611310 100644
--- a/frontend/src/app/components/docs/api-docs.component.ts
+++ b/frontend/src/app/components/docs/api-docs.component.ts
@@ -34,7 +34,9 @@ export class ApiDocsComponent implements OnInit {
   ngAfterViewInit() {
     const that = this;
     setTimeout( () => {
-      this.openEndpointContainer( this.route.snapshot.fragment );
+      if( this.route.snapshot.fragment ) {
+        this.openEndpointContainer( this.route.snapshot.fragment );
+      }
       window.addEventListener('scroll', function() {
         that.desktopDocsNavPosition = ( window.pageYOffset > 182 ) ? "fixed" : "relative";
       });
@@ -73,7 +75,16 @@ export class ApiDocsComponent implements OnInit {
   }
 
   anchorLinkClick( event: any ) {
-    const targetId = event.target.hash.substring(1);
+    let targetId = "";
+    if( event.target.nodeName === "A" ) {
+      targetId = event.target.hash.substring(1);
+    } else {
+      let element = event.target;
+      while( element.nodeName !== "A" ) {
+        element = element.parentElement;
+      }
+      targetId = element.hash.substring(1);
+    }
     if( this.route.snapshot.fragment === targetId ) {
       document.getElementById( targetId ).scrollIntoView();
     }
@@ -81,6 +92,7 @@ export class ApiDocsComponent implements OnInit {
   }
 
   openEndpointContainer( targetId ) {
+    const tabHeaderHeight = document.getElementById( targetId + "-tab-header" ).scrollHeight;
     if( ( window.innerWidth <= 992 ) && ( ( this.whichTab === 'rest' ) || ( this.whichTab === 'faq' ) ) && targetId ) {
       const endpointContainerEl = document.querySelector<HTMLElement>( "#" + targetId );
       const endpointContentEl = document.querySelector<HTMLElement>( "#" + targetId + " .endpoint-content" );
@@ -92,8 +104,8 @@ export class ApiDocsComponent implements OnInit {
         endpointContentEl.style.opacity = "0";
         endpointContentEl.classList.remove( "open" );
       } else {
-        endpointContainerEl.style.height = endPointContentElHeight + 90 + "px";
-        endpointContentEl.style.top = "90px";
+        endpointContainerEl.style.height = endPointContentElHeight + tabHeaderHeight + 28 + "px";
+        endpointContentEl.style.top = tabHeaderHeight + 28 + "px";
         endpointContentEl.style.opacity = "1";
         endpointContentEl.classList.add( "open" );
       }

From 88c50f7107e0c8cd807a15e2ef251b22586c7e3b Mon Sep 17 00:00:00 2001
From: hunicus <93150691+hunicus@users.noreply.github.com>
Date: Tue, 12 Apr 2022 15:33:24 -0400
Subject: [PATCH 12/17] Resolve conflict resulting from 315b759

---
 frontend/src/app/components/docs/docs.component.ts | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/frontend/src/app/components/docs/docs.component.ts b/frontend/src/app/components/docs/docs.component.ts
index 042ed435b..89bbd48b7 100644
--- a/frontend/src/app/components/docs/docs.component.ts
+++ b/frontend/src/app/components/docs/docs.component.ts
@@ -32,5 +32,10 @@ export class DocsComponent implements OnInit {
     this.env = this.stateService.env;
     this.showWebSocketTab = ( ! ( ( this.stateService.network === "bisq" ) || ( this.stateService.network === "liquidtestnet" ) ) );
     this.showFaqTab = ( this.env.BASE_MODULE === 'mempool' ) ? true : false;
+    document.querySelector<HTMLElement>( "html" ).style.scrollBehavior = "smooth";
+  }
+
+  ngOnDestroy(): void {
+    document.querySelector<HTMLElement>( "html" ).style.scrollBehavior = "auto";
   }
 }

From e50b58b8aa1716df03dedb7e73c8ffe7b8b2f679 Mon Sep 17 00:00:00 2001
From: hunicus <93150691+hunicus@users.noreply.github.com>
Date: Tue, 12 Apr 2022 15:58:20 -0400
Subject: [PATCH 13/17] Add live mempool blocks to faq (h/t @softsimon)

---
 frontend/src/app/components/docs/api-docs-data.ts    |  2 +-
 .../src/app/components/docs/api-docs.component.html  |  9 ++++++---
 .../src/app/components/docs/api-docs.component.scss  | 12 +++++++++++-
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/frontend/src/app/components/docs/api-docs-data.ts b/frontend/src/app/components/docs/api-docs-data.ts
index a369ac63b..3e7d442c7 100644
--- a/frontend/src/app/components/docs/api-docs-data.ts
+++ b/frontend/src/app/components/docs/api-docs-data.ts
@@ -4433,7 +4433,7 @@ export const faqData = [
     showConditions: bitcoinNetworks,
     fragment: "what-is-a-mempool-explorer",
     title: "What is a mempool explorer?",
-    answer: "<p>A mempool explorer is a tool that enables you to view real-time and historical information about a node's mempool, visualize its transactions, and search and view those transactions.</p><p>The mempool.space website invented the concept of visualizing a Bitcoin node's mempool as <b>projected blocks</b>. These blocks are the inspiration for our half-filled block logo.</p><p>Here's a snapshot of this visualization (which you can find on <a href='/'>the main dashboard</a>) as of block 729,556 in March 2022. Projected blocks are on the left of the dotted white line, and confirmed blocks are on the right.</p><iframe id='mempool-blocks' style='width: 100%;height: 275px;border: none' src='./resources/mempool-blocks.html' scrolling='no'></iframe>"
+    answer: "<p>A mempool explorer is a tool that enables you to view real-time and historical information about a node's mempool, visualize its transactions, and search and view those transactions.</p><p>The mempool.space website invented the concept of visualizing a Bitcoin node's mempool as <b>projected blocks</b>. These blocks are the inspiration for our half-filled block logo.</p><p>Projected blocks are on the left of the dotted white line, and confirmed blocks are on the right.</p>"
   },
   {
     type: "endpoint",
diff --git a/frontend/src/app/components/docs/api-docs.component.html b/frontend/src/app/components/docs/api-docs.component.html
index f33c777c9..6cb5839a0 100644
--- a/frontend/src/app/components/docs/api-docs.component.html
+++ b/frontend/src/app/components/docs/api-docs.component.html
@@ -1,6 +1,6 @@
 <ng-container *ngIf="{ val: network$ | async } as network">
   <div class="container-xl text-left">
-  
+
     <div id="faq" *ngIf="whichTab === 'faq'">
 
       <div id="doc-nav-desktop" class="hide-on-mobile" [ngClass]="desktopDocsNavPosition">
@@ -15,12 +15,15 @@
             <a id="{{ item.fragment + '-tab-header' }}" class="section-header" (click)="anchorLinkClick( $event )" [routerLink]="['./']" fragment="{{ item.fragment }}"><table><tr><td>{{ item.title }}</td><td><span>{{ item.category }}</span></td></tr></table></a>
             <div class="endpoint-content">
               <div class="endpoint" [innerHTML]="item.answer | noSanitize"></div>
+              <div class="blockchain-wrapper" *ngIf="item.fragment === 'what-is-a-mempool-explorer'">
+                <app-blockchain></app-blockchain>
+              </div>
             </div>
           </div>
         </div>
-        
+
       </div>
-      
+
     </div>
 
     <div id="restAPI" *ngIf="whichTab === 'rest'">
diff --git a/frontend/src/app/components/docs/api-docs.component.scss b/frontend/src/app/components/docs/api-docs.component.scss
index ce74cd951..91c85c346 100644
--- a/frontend/src/app/components/docs/api-docs.component.scss
+++ b/frontend/src/app/components/docs/api-docs.component.scss
@@ -187,6 +187,16 @@ h3 {
   border-radius: 0.5rem 0.5rem 0 0;
 }
 
+.blockchain-wrapper {
+  position: relative;
+  width: 100%;
+  overflow: auto;
+  scrollbar-width: none;
+}
+.blockchain-wrapper::-webkit-scrollbar {
+  display: none;
+}
+
 @media (max-width: 992px) {
 
   .hide-on-mobile {
@@ -239,7 +249,7 @@ h3 {
   h3 {
     display: none;
   }
-  
+
   .doc-item-container:last-of-type .endpoint-container {
     margin-bottom: 4rem;
   }

From 01f474628a19f9c24c237b5380e4e49383db49da Mon Sep 17 00:00:00 2001
From: hunicus <93150691+hunicus@users.noreply.github.com>
Date: Tue, 12 Apr 2022 18:06:32 -0400
Subject: [PATCH 14/17] Add websocket service to avoid issues with blocks

---
 frontend/src/app/components/docs/docs.component.ts | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/frontend/src/app/components/docs/docs.component.ts b/frontend/src/app/components/docs/docs.component.ts
index 3b18c1891..2d0d0b55a 100644
--- a/frontend/src/app/components/docs/docs.component.ts
+++ b/frontend/src/app/components/docs/docs.component.ts
@@ -1,6 +1,7 @@
 import { Component, OnInit, HostBinding } from '@angular/core';
 import { ActivatedRoute } from '@angular/router';
 import { Env, StateService } from 'src/app/services/state.service';
+import { WebsocketService } from 'src/app/services/websocket.service';
 
 @Component({
   selector: 'app-docs',
@@ -19,9 +20,11 @@ export class DocsComponent implements OnInit {
   constructor(
     private route: ActivatedRoute,
     private stateService: StateService,
+    private websocket: WebsocketService,
   ) { }
 
   ngOnInit(): void {
+    this.websocket.want(['blocks']);
     const url = this.route.snapshot.url;
     if( url[1].path === "faq" ) {
         this.activeTab = 0;
@@ -34,7 +37,7 @@ export class DocsComponent implements OnInit {
     this.env = this.stateService.env;
     this.showWebSocketTab = ( ! ( ( this.stateService.network === "bisq" ) || ( this.stateService.network === "liquidtestnet" ) ) );
     this.showFaqTab = ( this.env.BASE_MODULE === 'mempool' ) ? true : false;
-    
+
     document.querySelector<HTMLElement>( "html" ).style.scrollBehavior = "smooth";
   }
 

From bee0dbd40048e6ee031b186a61b3fd23c31b5620 Mon Sep 17 00:00:00 2001
From: nymkappa <vialjoris@hotmail.com>
Date: Wed, 13 Apr 2022 16:29:52 +0900
Subject: [PATCH 15/17] Cleanup mining related backend logs

---
 backend/src/api/blocks.ts                     | 23 ++++++++-----
 backend/src/api/mining.ts                     | 20 +++++++----
 backend/src/api/pools-parser.ts               |  6 ++--
 backend/src/index.ts                          | 12 ++++---
 backend/src/repositories/BlocksRepository.ts  | 34 +++++++++----------
 .../src/repositories/HashratesRepository.ts   | 20 ++++++-----
 backend/src/repositories/PoolsRepository.ts   |  9 +++--
 backend/src/tasks/pools-updater.ts            | 10 +++---
 8 files changed, 75 insertions(+), 59 deletions(-)

diff --git a/backend/src/api/blocks.ts b/backend/src/api/blocks.ts
index 1024107d0..4402f0d37 100644
--- a/backend/src/api/blocks.ts
+++ b/backend/src/api/blocks.ts
@@ -75,9 +75,12 @@ class Blocks {
           transactions.push(tx);
           transactionsFetched++;
         } catch (e) {
-          logger.debug('Error fetching block tx: ' + (e instanceof Error ? e.message : e));
           if (i === 0) {
-            throw new Error('Failed to fetch Coinbase transaction: ' + txIds[i]);
+            const msg = `Cannot fetch coinbase tx ${txIds[i]}. Reason: ` + (e instanceof Error ? e.message : e); 
+            logger.err(msg);
+            throw new Error(msg);
+          } else {
+            logger.err(`Cannot fetch tx ${txIds[i]}. Reason: ` + (e instanceof Error ? e.message : e));
           }
         }
       }
@@ -137,8 +140,8 @@ class Blocks {
         pool = await poolsRepository.$getUnknownPool();
       }
 
-      if (!pool) { // Something is wrong with the pools table, ignore pool indexing
-        logger.err('Unable to find pool, nor getting the unknown pool. Is the "pools" table empty?');
+      if (!pool) { // We should never have this situation in practise
+        logger.warn(`Cannot assign pool to block ${blockExtended.height} and 'unknown' pool does not exist. Check your "pools" table entries`);
         return blockExtended;
       }
 
@@ -214,11 +217,12 @@ class Blocks {
 
       const lastBlockToIndex = Math.max(0, currentBlockHeight - indexingBlockAmount + 1);
 
-      logger.info(`Indexing blocks from #${currentBlockHeight} to #${lastBlockToIndex}`);
+      logger.debug(`Indexing blocks from #${currentBlockHeight} to #${lastBlockToIndex}`);
 
       const chunkSize = 10000;
       let totaIndexed = await blocksRepository.$blockCount(null, null);
       let indexedThisRun = 0;
+      let newlyIndexed = 0;
       const startedAt = new Date().getTime() / 1000;
       let timer = new Date().getTime() / 1000;
 
@@ -228,12 +232,11 @@ class Blocks {
         const missingBlockHeights: number[] = await blocksRepository.$getMissingBlocksBetweenHeights(
           currentBlockHeight, endBlock);
         if (missingBlockHeights.length <= 0) {
-          logger.debug(`No missing blocks between #${currentBlockHeight} to #${endBlock}`);
           currentBlockHeight -= chunkSize;
           continue;
         }
 
-        logger.debug(`Indexing ${missingBlockHeights.length} blocks from #${currentBlockHeight} to #${endBlock}`);
+        logger.info(`Indexing ${missingBlockHeights.length} blocks from #${currentBlockHeight} to #${endBlock}`);
 
         for (const blockHeight of missingBlockHeights) {
           if (blockHeight < lastBlockToIndex) {
@@ -255,14 +258,16 @@ class Blocks {
           const block = BitcoinApi.convertBlock(await bitcoinClient.getBlock(blockHash));
           const transactions = await this.$getTransactionsExtended(blockHash, block.height, true, true);
           const blockExtended = await this.$getBlockExtended(block, transactions);
+
+          newlyIndexed++;
           await blocksRepository.$saveBlockInDatabase(blockExtended);
         }
 
         currentBlockHeight -= chunkSize;
       }
-      logger.info('Block indexing completed');
+      logger.info(`Indexed ${newlyIndexed} blocks`);
     } catch (e) {
-      logger.err('An error occured in $generateBlockDatabase(). Trying again later. ' + e);
+      logger.err('Block indexing failed. Trying again later. Reason: ' + (e instanceof Error ? e.message : e));
       this.blockIndexingStarted = false;
       return;
     }
diff --git a/backend/src/api/mining.ts b/backend/src/api/mining.ts
index 6b7d2e01d..201813899 100644
--- a/backend/src/api/mining.ts
+++ b/backend/src/api/mining.ts
@@ -142,8 +142,6 @@ class Mining {
     }
 
     try {
-      logger.info(`Indexing mining pools weekly hashrates`);
-
       const indexedTimestamp = await HashratesRepository.$getWeeklyHashrateTimestamps();
       const hashrates: any[] = [];
       const genesisTimestamp = 1231006505000; // bitcoin-cli getblock 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f
@@ -155,6 +153,7 @@ class Mining {
       const totalWeekIndexed = (await BlocksRepository.$blockCount(null, null)) / 1008;
       let indexedThisRun = 0;
       let totalIndexed = 0;
+      let newlyIndexed = 0;
       let startedAt = new Date().getTime();
 
       while (toTimestamp > genesisTimestamp) {
@@ -198,6 +197,7 @@ class Mining {
           });
         }
 
+        newlyIndexed += hashrates.length;
         await HashratesRepository.$saveHashrates(hashrates);
         hashrates.length = 0;
 
@@ -217,7 +217,9 @@ class Mining {
       }
       this.weeklyHashrateIndexingStarted = false;
       await HashratesRepository.$setLatestRunTimestamp('last_weekly_hashrates_indexing');
-      logger.info(`Weekly pools hashrate indexing completed`);
+      if (newlyIndexed > 0) {
+        logger.info(`Indexed ${newlyIndexed} pools weekly hashrate`);
+      }
     } catch (e) {
       this.weeklyHashrateIndexingStarted = false;
       throw e;
@@ -249,8 +251,6 @@ class Mining {
     }
 
     try {
-      logger.info(`Indexing network daily hashrate`);
-
       const indexedTimestamp = (await HashratesRepository.$getNetworkDailyHashrate(null)).map(hashrate => hashrate.timestamp);
       const genesisTimestamp = 1231006505000; // bitcoin-cli getblock 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f
       const lastMidnight = this.getDateMidnight(new Date());
@@ -260,6 +260,7 @@ class Mining {
       const totalDayIndexed = (await BlocksRepository.$blockCount(null, null)) / 144;
       let indexedThisRun = 0;
       let totalIndexed = 0;
+      let newlyIndexed = 0;
       let startedAt = new Date().getTime();
 
       while (toTimestamp > genesisTimestamp) {
@@ -294,6 +295,7 @@ class Mining {
         });
 
         if (hashrates.length > 10) {
+          newlyIndexed += hashrates.length;
           await HashratesRepository.$saveHashrates(hashrates);
           hashrates.length = 0;
         }
@@ -303,7 +305,8 @@ class Mining {
           const daysPerSeconds = (indexedThisRun / elapsedSeconds).toFixed(2);
           const formattedDate = new Date(fromTimestamp).toUTCString();
           const daysLeft = Math.round(totalDayIndexed - totalIndexed);
-          logger.debug(`Getting network daily hashrate for ${formattedDate} | ~${daysPerSeconds} days/sec | ~${daysLeft} days left to index`);
+          logger.debug(`Getting network daily hashrate for ${formattedDate} | ~${daysPerSeconds} days/sec | ` +
+            `~${daysLeft} days left to index`);
           startedAt = new Date().getTime();
           indexedThisRun = 0;
         }
@@ -323,11 +326,14 @@ class Mining {
         });
       }
 
+      newlyIndexed += hashrates.length;
       await HashratesRepository.$saveHashrates(hashrates);
 
       await HashratesRepository.$setLatestRunTimestamp('last_hashrates_indexing');
       this.hashrateIndexingStarted = false;
-      logger.info(`Daily network hashrate indexing completed`);
+      if (newlyIndexed > 0) {
+        logger.info(`Indexed ${newlyIndexed} day of network hashrate`);
+      }
     } catch (e) {
       this.hashrateIndexingStarted = false;
       throw e;
diff --git a/backend/src/api/pools-parser.ts b/backend/src/api/pools-parser.ts
index dee95912a..fc379cc8c 100644
--- a/backend/src/api/pools-parser.ts
+++ b/backend/src/api/pools-parser.ts
@@ -64,7 +64,7 @@ class PoolsParser {
     try {
       [existingPools] = await connection.query<any>({ sql: 'SELECT * FROM pools;', timeout: 120000 });
     } catch (e) {
-      logger.err('Unable to get existing pools from the database, skipping pools.json import');
+      logger.err('Cannot get existing pools from the database, skipping pools.json import');
       connection.release();
       return;
     }
@@ -97,7 +97,7 @@ class PoolsParser {
       if (slug === undefined) {
         // Only keep alphanumerical
         slug = poolNames[i].replace(/[^a-z0-9]/gi, '').toLowerCase();
-        logger.debug(`No slug found for '${poolNames[i]}', generating it => '${slug}'`);
+        logger.warn(`No slug found for '${poolNames[i]}', generating it => '${slug}'`);
       }
 
       if (existingPools.find((pool) => pool.name === poolNames[i]) !== undefined) {
@@ -155,7 +155,7 @@ class PoolsParser {
       logger.info('Mining pools.json import completed');
     } catch (e) {
       connection.release();
-      logger.err(`Unable to import pools in the database!`);
+      logger.err(`Unable to import pools in the database`);
       throw e;
     }
   }
diff --git a/backend/src/index.ts b/backend/src/index.ts
index c8e98c0b7..cd8d55757 100644
--- a/backend/src/index.ts
+++ b/backend/src/index.ts
@@ -93,7 +93,7 @@ class Server {
       try {
         if (process.env.npm_config_reindex != undefined) { // Re-index requests
           const tables = process.env.npm_config_reindex.split(',');
-          logger.warn(`Indexed data for "${process.env.npm_config_reindex}" tables will be erased in 5 seconds from now (using '--reindex') ...`);
+          logger.warn(`Indexed data for "${process.env.npm_config_reindex}" tables will be erased in 5 seconds (using '--reindex')`);
           await Common.sleep(5000);
           await databaseMigration.$truncateIndexedData(tables);
         }
@@ -169,8 +169,12 @@ class Server {
   }
 
   async $resetHashratesIndexingState() {
-    await HashratesRepository.$setLatestRunTimestamp('last_hashrates_indexing', 0);
-    await HashratesRepository.$setLatestRunTimestamp('last_weekly_hashrates_indexing', 0);
+    try {
+      await HashratesRepository.$setLatestRunTimestamp('last_hashrates_indexing', 0);
+      await HashratesRepository.$setLatestRunTimestamp('last_weekly_hashrates_indexing', 0);
+    } catch (e) {
+      logger.err(`Cannot reset hashrate indexing timestamps. Reason: ` + (e instanceof Error ? e.message : e));
+    }
   }
 
   async $runIndexingWhenReady() {
@@ -188,7 +192,7 @@ class Server {
       await mining.$generateNetworkHashrateHistory();
       await mining.$generatePoolHashrateHistory();
     } catch (e) {
-      logger.err(`Unable to run indexing right now, trying again later. ` + e);
+      logger.err(`Indexing failed, trying again later. Reason: ` + (e instanceof Error ? e.message : e));
     }
   }
 
diff --git a/backend/src/repositories/BlocksRepository.ts b/backend/src/repositories/BlocksRepository.ts
index 2ec97ce88..d5decfcaa 100644
--- a/backend/src/repositories/BlocksRepository.ts
+++ b/backend/src/repositories/BlocksRepository.ts
@@ -56,11 +56,11 @@ class BlocksRepository {
       connection.release();
     } catch (e: any) {
       connection.release();
-      if (e.errno === 1062) { // ER_DUP_ENTRY
+      if (e.errno === 1062) { // ER_DUP_ENTRY - This scenario is possible upon node backend restart
         logger.debug(`$saveBlockInDatabase() - Block ${block.height} has already been indexed, ignoring`);
       } else {
         connection.release();
-        logger.err('$saveBlockInDatabase() error: ' + (e instanceof Error ? e.message : e));
+        logger.err('Cannot save indexed block into db. Reason: ' + (e instanceof Error ? e.message : e));
         throw e;
       }
     }
@@ -93,7 +93,7 @@ class BlocksRepository {
       return missingBlocksHeights;
     } catch (e) {
       connection.release();
-      logger.err('$getMissingBlocksBetweenHeights() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot retrieve blocks list to index. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -130,7 +130,7 @@ class BlocksRepository {
       return rows;
     } catch (e) {
       connection.release();
-      logger.err('$getEmptyBlocks() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot count empty blocks. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -168,7 +168,7 @@ class BlocksRepository {
       return <number>rows[0].blockCount;
     } catch (e) {
       connection.release();
-      logger.err('$blockCount() error' + (e instanceof Error ? e.message : e));
+      logger.err(`Cannot count blocks for this pool (using offset). Reason: ` + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -208,7 +208,7 @@ class BlocksRepository {
       return <number>rows[0];
     } catch (e) {
       connection.release();
-      logger.err('$blockCountBetweenTimestamp() error' + (e instanceof Error ? e.message : e));
+      logger.err(`Cannot count blocks for this pool (using timestamps). Reason: ` + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -235,7 +235,7 @@ class BlocksRepository {
       return <number>rows[0].blockTimestamp;
     } catch (e) {
       connection.release();
-      logger.err('$oldestBlockTimestamp() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot get oldest indexed block timestamp. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -278,7 +278,7 @@ class BlocksRepository {
       return blocks;
     } catch (e) {
       connection.release();
-      logger.err('$getBlocksByPool() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot get blocks for this pool. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -308,7 +308,7 @@ class BlocksRepository {
       return rows[0];
     } catch (e) {
       connection.release();
-      logger.err('$getBlockByHeight() error' + (e instanceof Error ? e.message : e));
+      logger.err(`Cannot get indexed block ${height}. Reason: ` + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -365,7 +365,7 @@ class BlocksRepository {
       return rows;
     } catch (e) {
       connection.release();
-      logger.err('$getBlocksDifficulty() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot generate difficulty history. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -392,7 +392,7 @@ class BlocksRepository {
       return rows[0];
     } catch (e) {
       connection.release();
-      logger.err('$getBlockStats() error: ' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot generate reward stats. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -410,7 +410,7 @@ class BlocksRepository {
 
       for (let i = 0; i < lastBlocks.length - 1; ++i) {
         if (lastBlocks[i].previous_block_hash !== lastBlocks[i + 1].hash) {
-          logger.notice(`Chain divergence detected at block ${lastBlocks[i].height}, re-indexing most recent data`);
+          logger.warn(`Chain divergence detected at block ${lastBlocks[i].height}, re-indexing most recent data`);
           return false;
         }
       }
@@ -427,21 +427,21 @@ class BlocksRepository {
    * Delete $count blocks from the database
    */
   public async $deleteBlocks(count: number) {
+    logger.info(`Delete ${count} most recent indexed blocks from the database`);
     let connection;
 
     try {
       connection = await DB.getConnection();
-      logger.debug(`Delete ${count} most recent indexed blocks from the database`);
       await connection.query(`DELETE FROM blocks ORDER BY height DESC LIMIT ${count};`);
     } catch (e) {
-      logger.err('$deleteBlocks() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot delete recent indexed blocks. Reason: ' + (e instanceof Error ? e.message : e));
     }
 
     connection.release();
   }
 
   /**
-   * Get the historical averaged block reward and total fees
+   * Get the historical averaged block fees
    */
   public async $getHistoricalBlockFees(div: number, interval: string | null): Promise<any> {
     let connection;
@@ -464,7 +464,7 @@ class BlocksRepository {
       return rows;
     } catch (e) {
       connection.release();
-      logger.err('$getHistoricalBlockFees() error: ' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot generate block fees history. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -493,7 +493,7 @@ class BlocksRepository {
       return rows;
     } catch (e) {
       connection.release();
-      logger.err('$getHistoricalBlockRewards() error: ' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot generate block rewards history. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
diff --git a/backend/src/repositories/HashratesRepository.ts b/backend/src/repositories/HashratesRepository.ts
index 6f994342a..e63fe5ddb 100644
--- a/backend/src/repositories/HashratesRepository.ts
+++ b/backend/src/repositories/HashratesRepository.ts
@@ -27,7 +27,7 @@ class HashratesRepository {
       connection.release();
     } catch (e: any) {
       connection.release();
-      logger.err('$saveHashrateInDatabase() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot save indexed hashrate into db. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -56,7 +56,7 @@ class HashratesRepository {
       return rows;
     } catch (e) {
       connection.release();
-      logger.err('$getNetworkDailyHashrate() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot fetch network hashrate history. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -76,7 +76,7 @@ class HashratesRepository {
       return rows.map(row => row.timestamp);
     } catch (e) {
       connection.release();
-      logger.err('$getWeeklyHashrateTimestamps() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot retreive indexed weekly hashrate timestamps. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -112,7 +112,7 @@ class HashratesRepository {
       return rows;
     } catch (e) {
       connection.release();
-      logger.err('$getPoolsWeeklyHashrate() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot fetch weekly pools hashrate history. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -146,7 +146,7 @@ class HashratesRepository {
       connection.release();
     } catch (e) {
       connection.release();
-      logger.err('$getPoolWeeklyHashrate() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot fetch hashrate start/end timestamps for this pool. Reason: ' + (e instanceof Error ? e.message : e));
     }
 
     // Get hashrates entries between boundaries
@@ -164,7 +164,7 @@ class HashratesRepository {
       return rows;
     } catch (e) {
       connection.release();
-      logger.err('$getPoolWeeklyHashrate() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot fetch pool hashrate history for this pool. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -181,6 +181,8 @@ class HashratesRepository {
       connection.release();
     } catch (e) {
       connection.release();
+      logger.err(`Cannot set last indexing timestamp for ${key}. Reason: ` + (e instanceof Error ? e.message : e));
+      throw e;
     }
   }
 
@@ -201,7 +203,7 @@ class HashratesRepository {
       return rows[0]['number'];
     } catch (e) {
       connection.release();
-      logger.err('$setLatestRunTimestamp() error' + (e instanceof Error ? e.message : e));
+      logger.err(`Cannot retreive last indexing timestamp for ${key}. Reason: ` + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -210,7 +212,7 @@ class HashratesRepository {
    * Delete most recent data points for re-indexing
    */
   public async $deleteLastEntries() {
-    logger.debug(`Delete latest hashrates data points from the database`);
+    logger.info(`Delete latest hashrates data points from the database`);
 
     let connection;
     try {
@@ -223,7 +225,7 @@ class HashratesRepository {
       await this.$setLatestRunTimestamp('last_hashrates_indexing', 0);
       await this.$setLatestRunTimestamp('last_weekly_hashrates_indexing', 0);
     } catch (e) {
-      logger.err('$deleteLastEntries() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot delete latest hashrates data points. Reason: ' + (e instanceof Error ? e.message : e));
     }
 
     connection.release();
diff --git a/backend/src/repositories/PoolsRepository.ts b/backend/src/repositories/PoolsRepository.ts
index 65f6f4353..9d609f761 100644
--- a/backend/src/repositories/PoolsRepository.ts
+++ b/backend/src/repositories/PoolsRepository.ts
@@ -42,7 +42,6 @@ class PoolsRepository {
     query += ` GROUP BY pool_id
       ORDER BY COUNT(height) DESC`;
 
-    // logger.debug(query);
     const connection = await DB.getConnection();
     try {
       const [rows] = await connection.query(query);
@@ -51,7 +50,7 @@ class PoolsRepository {
       return <PoolInfo[]>rows;
     } catch (e) {
       connection.release();
-      logger.err('$getPoolsInfo() error' + (e instanceof Error ? e.message : e));
+      logger.err(`Cannot generate pools stats. Reason: ` + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -73,7 +72,7 @@ class PoolsRepository {
       return <PoolInfo[]>rows;
     } catch (e) {
       connection.release();
-      logger.err('$getPoolsInfoBetween() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot generate pools blocks count. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
@@ -95,7 +94,7 @@ class PoolsRepository {
       connection.release();
 
       if (rows.length < 1) {
-        logger.debug(`$getPool(): slug does not match any known pool`);
+        logger.debug(`This slug does not match any known pool`);
         return null;
       }
 
@@ -109,7 +108,7 @@ class PoolsRepository {
       return rows[0];
     } catch (e) {
       connection.release();
-      logger.err('$getPool() error' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot get pool from db. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
diff --git a/backend/src/tasks/pools-updater.ts b/backend/src/tasks/pools-updater.ts
index b3838244a..22c2b16b0 100644
--- a/backend/src/tasks/pools-updater.ts
+++ b/backend/src/tasks/pools-updater.ts
@@ -48,7 +48,7 @@ class PoolsUpdater {
 
     } catch (e) {
       this.lastRun = now - (oneWeek - oneDay); // Try again in 24h instead of waiting next week
-      logger.err('PoolsUpdater failed. Will try again in 24h. Error: ' + e);
+      logger.err('PoolsUpdater failed. Will try again in 24h. Reason: '  + (e instanceof Error ? e.message : e));
     }
   }
 
@@ -71,7 +71,7 @@ class PoolsUpdater {
       await connection.query(`INSERT INTO state VALUES('pools_json_sha', NULL, '${githubSha}')`);
       connection.release();
     } catch (e) {
-      logger.err('Unable save github pools.json sha into the DB, error: ' + e);
+      logger.err('Cannot save github pools.json sha into the db. Reason: '  + (e instanceof Error ? e.message : e));
       connection.release();
       return undefined;
     }
@@ -88,7 +88,7 @@ class PoolsUpdater {
       connection.release();
       return (rows.length > 0 ? rows[0].string : undefined);
     } catch (e) {
-      logger.err('Unable fetch pools.json sha from DB, error: ' + e);
+      logger.err('Cannot fetch pools.json sha from db. Reason: '  + (e instanceof Error ? e.message : e));
       connection.release();
       return undefined;
     }
@@ -106,7 +106,7 @@ class PoolsUpdater {
       }
     }
 
-    logger.err('Unable to find latest pools.json sha from github');
+    logger.err('Cannot to find latest pools.json sha from github api response');
     return undefined;
   }
 
@@ -138,7 +138,7 @@ class PoolsUpdater {
       });
 
       request.on('error', (error) => {
-        logger.err('Query failed with error: ' + error);
+        logger.err('Github API query failed. Reason: '  + error);
         reject(error);
       })
     });

From 6fb0571b06004710d02d960a61c4b5691d3fa75b Mon Sep 17 00:00:00 2001
From: nymkappa <vialjoris@hotmail.com>
Date: Tue, 12 Apr 2022 15:15:57 +0900
Subject: [PATCH 16/17] Refactor database pool use

---
 backend/src/api/database-migration.ts         | 156 ++++++++----------
 backend/src/api/liquid/elements-parser.ts     |  16 +-
 backend/src/api/pools-parser.ts               |  21 +--
 backend/src/api/statistics.ts                 |  74 +++------
 backend/src/database.ts                       |  39 +++--
 backend/src/index.ts                          |   2 +-
 backend/src/repositories/BlocksRepository.ts  | 104 ++----------
 .../src/repositories/HashratesRepository.ts   |  59 ++-----
 backend/src/repositories/PoolsRepository.ts   |  27 +--
 backend/src/tasks/pools-updater.ts            |  24 +--
 10 files changed, 164 insertions(+), 358 deletions(-)

diff --git a/backend/src/api/database-migration.ts b/backend/src/api/database-migration.ts
index 3978a7d85..ed93d695d 100644
--- a/backend/src/api/database-migration.ts
+++ b/backend/src/api/database-migration.ts
@@ -1,4 +1,3 @@
-import { PoolConnection } from 'mysql2/promise';
 import config from '../config';
 import { DB } from '../database';
 import logger from '../logger';
@@ -77,116 +76,112 @@ class DatabaseMigration {
     await this.$setStatisticsAddedIndexedFlag(databaseSchemaVersion);
 
     const isBitcoin = ['mainnet', 'testnet', 'signet'].includes(config.MEMPOOL.NETWORK);
-    const connection = await DB.getConnection();
     try {
-      await this.$executeQuery(connection, this.getCreateElementsTableQuery(), await this.$checkIfTableExists('elements_pegs'));
-      await this.$executeQuery(connection, this.getCreateStatisticsQuery(), await this.$checkIfTableExists('statistics'));
+      await this.$executeQuery(this.getCreateElementsTableQuery(), await this.$checkIfTableExists('elements_pegs'));
+      await this.$executeQuery(this.getCreateStatisticsQuery(), await this.$checkIfTableExists('statistics'));
       if (databaseSchemaVersion < 2 && this.statisticsAddedIndexed === false) {
-        await this.$executeQuery(connection, `CREATE INDEX added ON statistics (added);`);
+        await this.$executeQuery(`CREATE INDEX added ON statistics (added);`);
       }
       if (databaseSchemaVersion < 3) {
-        await this.$executeQuery(connection, this.getCreatePoolsTableQuery(), await this.$checkIfTableExists('pools'));
+        await this.$executeQuery(this.getCreatePoolsTableQuery(), await this.$checkIfTableExists('pools'));
       }
       if (databaseSchemaVersion < 4) {
-        await this.$executeQuery(connection, 'DROP table IF EXISTS blocks;');
-        await this.$executeQuery(connection, this.getCreateBlocksTableQuery(), await this.$checkIfTableExists('blocks'));
+        await this.$executeQuery('DROP table IF EXISTS blocks;');
+        await this.$executeQuery(this.getCreateBlocksTableQuery(), await this.$checkIfTableExists('blocks'));
       }
       if (databaseSchemaVersion < 5 && isBitcoin === true) {
         logger.warn(`'blocks' table has been truncated. Re-indexing from scratch.`);
-        await this.$executeQuery(connection, 'TRUNCATE blocks;'); // Need to re-index
-        await this.$executeQuery(connection, 'ALTER TABLE blocks ADD `reward` double unsigned NOT NULL DEFAULT "0"');
+        await this.$executeQuery('TRUNCATE blocks;'); // Need to re-index
+        await this.$executeQuery('ALTER TABLE blocks ADD `reward` double unsigned NOT NULL DEFAULT "0"');
       }
 
       if (databaseSchemaVersion < 6 && isBitcoin === true) {
         logger.warn(`'blocks' table has been truncated. Re-indexing from scratch.`);
-        await this.$executeQuery(connection, 'TRUNCATE blocks;');  // Need to re-index
+        await this.$executeQuery('TRUNCATE blocks;');  // Need to re-index
         // Cleanup original blocks fields type
-        await this.$executeQuery(connection, 'ALTER TABLE blocks MODIFY `height` integer unsigned NOT NULL DEFAULT "0"');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks MODIFY `tx_count` smallint unsigned NOT NULL DEFAULT "0"');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks MODIFY `size` integer unsigned NOT NULL DEFAULT "0"');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks MODIFY `weight` integer unsigned NOT NULL DEFAULT "0"');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks MODIFY `difficulty` double NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks MODIFY `height` integer unsigned NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks MODIFY `tx_count` smallint unsigned NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks MODIFY `size` integer unsigned NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks MODIFY `weight` integer unsigned NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks MODIFY `difficulty` double NOT NULL DEFAULT "0"');
         // We also fix the pools.id type so we need to drop/re-create the foreign key
-        await this.$executeQuery(connection, 'ALTER TABLE blocks DROP FOREIGN KEY IF EXISTS `blocks_ibfk_1`');
-        await this.$executeQuery(connection, 'ALTER TABLE pools MODIFY `id` smallint unsigned AUTO_INCREMENT');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks MODIFY `pool_id` smallint unsigned NULL');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks ADD FOREIGN KEY (`pool_id`) REFERENCES `pools` (`id`)');
+        await this.$executeQuery('ALTER TABLE blocks DROP FOREIGN KEY IF EXISTS `blocks_ibfk_1`');
+        await this.$executeQuery('ALTER TABLE pools MODIFY `id` smallint unsigned AUTO_INCREMENT');
+        await this.$executeQuery('ALTER TABLE blocks MODIFY `pool_id` smallint unsigned NULL');
+        await this.$executeQuery('ALTER TABLE blocks ADD FOREIGN KEY (`pool_id`) REFERENCES `pools` (`id`)');
         // Add new block indexing fields
-        await this.$executeQuery(connection, 'ALTER TABLE blocks ADD `version` integer unsigned NOT NULL DEFAULT "0"');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks ADD `bits` integer unsigned NOT NULL DEFAULT "0"');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks ADD `nonce` bigint unsigned NOT NULL DEFAULT "0"');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks ADD `merkle_root` varchar(65) NOT NULL DEFAULT ""');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks ADD `previous_block_hash` varchar(65) NULL');
+        await this.$executeQuery('ALTER TABLE blocks ADD `version` integer unsigned NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks ADD `bits` integer unsigned NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks ADD `nonce` bigint unsigned NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks ADD `merkle_root` varchar(65) NOT NULL DEFAULT ""');
+        await this.$executeQuery('ALTER TABLE blocks ADD `previous_block_hash` varchar(65) NULL');
       }
 
       if (databaseSchemaVersion < 7 && isBitcoin === true) {
-        await this.$executeQuery(connection, 'DROP table IF EXISTS hashrates;');
-        await this.$executeQuery(connection, this.getCreateDailyStatsTableQuery(), await this.$checkIfTableExists('hashrates'));
+        await this.$executeQuery('DROP table IF EXISTS hashrates;');
+        await this.$executeQuery(this.getCreateDailyStatsTableQuery(), await this.$checkIfTableExists('hashrates'));
       }
 
       if (databaseSchemaVersion < 8 && isBitcoin === true) {
         logger.warn(`'hashrates' table has been truncated. Re-indexing from scratch.`);
-        await this.$executeQuery(connection, 'TRUNCATE hashrates;'); // Need to re-index
-        await this.$executeQuery(connection, 'ALTER TABLE `hashrates` DROP INDEX `PRIMARY`');
-        await this.$executeQuery(connection, 'ALTER TABLE `hashrates` ADD `id` int NOT NULL AUTO_INCREMENT PRIMARY KEY FIRST');
-        await this.$executeQuery(connection, 'ALTER TABLE `hashrates` ADD `share` float NOT NULL DEFAULT "0"');
-        await this.$executeQuery(connection, 'ALTER TABLE `hashrates` ADD `type` enum("daily", "weekly") DEFAULT "daily"');
+        await this.$executeQuery('TRUNCATE hashrates;'); // Need to re-index
+        await this.$executeQuery('ALTER TABLE `hashrates` DROP INDEX `PRIMARY`');
+        await this.$executeQuery('ALTER TABLE `hashrates` ADD `id` int NOT NULL AUTO_INCREMENT PRIMARY KEY FIRST');
+        await this.$executeQuery('ALTER TABLE `hashrates` ADD `share` float NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE `hashrates` ADD `type` enum("daily", "weekly") DEFAULT "daily"');
       }
 
       if (databaseSchemaVersion < 9 && isBitcoin === true) {
         logger.warn(`'hashrates' table has been truncated. Re-indexing from scratch.`);
-        await this.$executeQuery(connection, 'TRUNCATE hashrates;'); // Need to re-index
-        await this.$executeQuery(connection, 'ALTER TABLE `state` CHANGE `name` `name` varchar(100)');
-        await this.$executeQuery(connection, 'ALTER TABLE `hashrates` ADD UNIQUE `hashrate_timestamp_pool_id` (`hashrate_timestamp`, `pool_id`)');
+        await this.$executeQuery('TRUNCATE hashrates;'); // Need to re-index
+        await this.$executeQuery('ALTER TABLE `state` CHANGE `name` `name` varchar(100)');
+        await this.$executeQuery('ALTER TABLE `hashrates` ADD UNIQUE `hashrate_timestamp_pool_id` (`hashrate_timestamp`, `pool_id`)');
       }
 
       if (databaseSchemaVersion < 10 && isBitcoin === true) {
-        await this.$executeQuery(connection, 'ALTER TABLE `blocks` ADD INDEX `blockTimestamp` (`blockTimestamp`)');
+        await this.$executeQuery('ALTER TABLE `blocks` ADD INDEX `blockTimestamp` (`blockTimestamp`)');
       }
 
       if (databaseSchemaVersion < 11 && isBitcoin === true) {
         logger.warn(`'blocks' table has been truncated. Re-indexing from scratch.`);
-        await this.$executeQuery(connection, 'TRUNCATE blocks;'); // Need to re-index
-        await this.$executeQuery(connection, `ALTER TABLE blocks
+        await this.$executeQuery('TRUNCATE blocks;'); // Need to re-index
+        await this.$executeQuery(`ALTER TABLE blocks
           ADD avg_fee INT UNSIGNED NULL,
           ADD avg_fee_rate INT UNSIGNED NULL
         `);
-        await this.$executeQuery(connection, 'ALTER TABLE blocks MODIFY `reward` BIGINT UNSIGNED NOT NULL DEFAULT "0"');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks MODIFY `median_fee` INT UNSIGNED NOT NULL DEFAULT "0"');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks MODIFY `fees` INT UNSIGNED NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks MODIFY `reward` BIGINT UNSIGNED NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks MODIFY `median_fee` INT UNSIGNED NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks MODIFY `fees` INT UNSIGNED NOT NULL DEFAULT "0"');
       }
 
       if (databaseSchemaVersion < 12 && isBitcoin === true) {
         // No need to re-index because the new data type can contain larger values
-        await this.$executeQuery(connection, 'ALTER TABLE blocks MODIFY `fees` BIGINT UNSIGNED NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks MODIFY `fees` BIGINT UNSIGNED NOT NULL DEFAULT "0"');
       }
 
       if (databaseSchemaVersion < 13 && isBitcoin === true) {
-        await this.$executeQuery(connection, 'ALTER TABLE blocks MODIFY `difficulty` DOUBLE UNSIGNED NOT NULL DEFAULT "0"');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks MODIFY `median_fee` BIGINT UNSIGNED NOT NULL DEFAULT "0"');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks MODIFY `avg_fee` BIGINT UNSIGNED NOT NULL DEFAULT "0"');
-        await this.$executeQuery(connection, 'ALTER TABLE blocks MODIFY `avg_fee_rate` BIGINT UNSIGNED NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks MODIFY `difficulty` DOUBLE UNSIGNED NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks MODIFY `median_fee` BIGINT UNSIGNED NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks MODIFY `avg_fee` BIGINT UNSIGNED NOT NULL DEFAULT "0"');
+        await this.$executeQuery('ALTER TABLE blocks MODIFY `avg_fee_rate` BIGINT UNSIGNED NOT NULL DEFAULT "0"');
       }
 
       if (databaseSchemaVersion < 14 && isBitcoin === true) {
         logger.warn(`'hashrates' table has been truncated. Re-indexing from scratch.`);
-        await this.$executeQuery(connection, 'TRUNCATE hashrates;'); // Need to re-index
-        await this.$executeQuery(connection, 'ALTER TABLE `hashrates` DROP FOREIGN KEY `hashrates_ibfk_1`');
-        await this.$executeQuery(connection, 'ALTER TABLE `hashrates` MODIFY `pool_id` SMALLINT UNSIGNED NOT NULL DEFAULT "0"');
+        await this.$executeQuery('TRUNCATE hashrates;'); // Need to re-index
+        await this.$executeQuery('ALTER TABLE `hashrates` DROP FOREIGN KEY `hashrates_ibfk_1`');
+        await this.$executeQuery('ALTER TABLE `hashrates` MODIFY `pool_id` SMALLINT UNSIGNED NOT NULL DEFAULT "0"');
       }
 
       if (databaseSchemaVersion < 16 && isBitcoin === true) {
         logger.warn(`'hashrates' table has been truncated. Re-indexing from scratch.`);
-        await this.$executeQuery(connection, 'TRUNCATE hashrates;'); // Need to re-index because we changed timestamps
+        await this.$executeQuery('TRUNCATE hashrates;'); // Need to re-index because we changed timestamps
       }
 
       if (databaseSchemaVersion < 17 && isBitcoin === true) {
-        await this.$executeQuery(connection, 'ALTER TABLE `pools` ADD `slug` CHAR(50) NULL');
+        await this.$executeQuery('ALTER TABLE `pools` ADD `slug` CHAR(50) NULL');
       }
-
-      connection.release();
     } catch (e) {
-      connection.release();
       throw e;
     }
   }
@@ -203,13 +198,11 @@ class DatabaseMigration {
       return;
     }
 
-    const connection = await DB.getConnection();
-
     try {
       // We don't use "CREATE INDEX IF NOT EXISTS" because it is not supported on old mariadb version 5.X
       const query = `SELECT COUNT(1) hasIndex FROM INFORMATION_SCHEMA.STATISTICS
         WHERE table_schema=DATABASE() AND table_name='statistics' AND index_name='added';`;
-      const [rows] = await this.$executeQuery(connection, query, true);
+      const [rows] = await this.$executeQuery(query, true);
       if (rows[0].hasIndex === 0) {
         logger.debug('MIGRATIONS: `statistics.added` is not indexed');
         this.statisticsAddedIndexed = false;
@@ -223,28 +216,24 @@ class DatabaseMigration {
       logger.err('MIGRATIONS: Unable to check if `statistics.added` INDEX exist or not.');
       this.statisticsAddedIndexed = true;
     }
-
-    connection.release();
   }
 
   /**
    * Small query execution wrapper to log all executed queries
    */
-  private async $executeQuery(connection: PoolConnection, query: string, silent: boolean = false): Promise<any> {
+  private async $executeQuery(query: string, silent: boolean = false): Promise<any> {
     if (!silent) {
       logger.debug('MIGRATIONS: Execute query:\n' + query);
     }
-    return connection.query<any>({ sql: query, timeout: this.queryTimeout });
+    return DB.query({ sql: query, timeout: this.queryTimeout });
   }
 
   /**
    * Check if 'table' exists in the database
    */
   private async $checkIfTableExists(table: string): Promise<boolean> {
-    const connection = await DB.getConnection();
     const query = `SELECT COUNT(*) FROM information_schema.tables WHERE table_schema = '${config.DATABASE.DATABASE}' AND TABLE_NAME = '${table}'`;
-    const [rows] = await connection.query<any>({ sql: query, timeout: this.queryTimeout });
-    connection.release();
+    const [rows] = await DB.query({ sql: query, timeout: this.queryTimeout });
     return rows[0]['COUNT(*)'] === 1;
   }
 
@@ -252,10 +241,8 @@ class DatabaseMigration {
    * Get current database version
    */
   private async $getSchemaVersionFromDatabase(): Promise<number> {
-    const connection = await DB.getConnection();
     const query = `SELECT number FROM state WHERE name = 'schema_version';`;
-    const [rows] = await this.$executeQuery(connection, query, true);
-    connection.release();
+    const [rows] = await this.$executeQuery(query, true);
     return rows[0]['number'];
   }
 
@@ -263,8 +250,6 @@ class DatabaseMigration {
    * Create the `state` table
    */
   private async $createMigrationStateTable(): Promise<void> {
-    const connection = await DB.getConnection();
-
     try {
       const query = `CREATE TABLE IF NOT EXISTS state (
         name varchar(25) NOT NULL,
@@ -272,15 +257,12 @@ class DatabaseMigration {
         string varchar(100) NULL,
         CONSTRAINT name_unique UNIQUE (name)
       ) ENGINE=InnoDB DEFAULT CHARSET=utf8;`;
-      await this.$executeQuery(connection, query);
+      await this.$executeQuery(query);
 
       // Set initial values
-      await this.$executeQuery(connection, `INSERT INTO state VALUES('schema_version', 0, NULL);`);
-      await this.$executeQuery(connection, `INSERT INTO state VALUES('last_elements_block', 0, NULL);`);
-
-      connection.release();
+      await this.$executeQuery(`INSERT INTO state VALUES('schema_version', 0, NULL);`);
+      await this.$executeQuery(`INSERT INTO state VALUES('last_elements_block', 0, NULL);`);
     } catch (e) {
-      connection.release();
       throw e;
     }
   }
@@ -295,18 +277,14 @@ class DatabaseMigration {
     }
     transactionQueries.push(this.getUpdateToLatestSchemaVersionQuery());
 
-    const connection = await DB.getConnection();
     try {
-      await this.$executeQuery(connection, 'START TRANSACTION;');
+      await this.$executeQuery('START TRANSACTION;');
       for (const query of transactionQueries) {
-        await this.$executeQuery(connection, query);
+        await this.$executeQuery(query);
       }
-      await this.$executeQuery(connection, 'COMMIT;');
-
-      connection.release();
+      await this.$executeQuery('COMMIT;');
     } catch (e) {
-      await this.$executeQuery(connection, 'ROLLBACK;');
-      connection.release();
+      await this.$executeQuery('ROLLBACK;');
       throw e;
     }
   }
@@ -346,14 +324,12 @@ class DatabaseMigration {
    * Print current database version
    */
   private async $printDatabaseVersion() {
-    const connection = await DB.getConnection();
     try {
-      const [rows] = await this.$executeQuery(connection, 'SELECT VERSION() as version;', true);
+      const [rows] = await this.$executeQuery('SELECT VERSION() as version;', true);
       logger.debug(`MIGRATIONS: Database engine version '${rows[0].version}'`);
     } catch (e) {
       logger.debug(`MIGRATIONS: Could not fetch database engine version. ` + e);
     }
-    connection.release();
   }
 
   // Couple of wrappers to clean the main logic
@@ -490,24 +466,22 @@ class DatabaseMigration {
   public async $truncateIndexedData(tables: string[]) {
     const allowedTables = ['blocks', 'hashrates'];
 
-    const connection = await DB.getConnection();
     try {
       for (const table of tables) {
         if (!allowedTables.includes(table)) {
           logger.debug(`Table ${table} cannot to be re-indexed (not allowed)`);
           continue;
-        };
+        }
 
-        await this.$executeQuery(connection, `TRUNCATE ${table}`, true);
+        await this.$executeQuery(`TRUNCATE ${table}`, true);
         if (table === 'hashrates') {
-          await this.$executeQuery(connection, 'UPDATE state set number = 0 where name = "last_hashrates_indexing"', true);
+          await this.$executeQuery('UPDATE state set number = 0 where name = "last_hashrates_indexing"', true);
         }
         logger.notice(`Table ${table} has been truncated`);
       }
     } catch (e) {
       logger.warn(`Unable to erase indexed data`);
     }
-    connection.release();
   }
 }
 
diff --git a/backend/src/api/liquid/elements-parser.ts b/backend/src/api/liquid/elements-parser.ts
index 24c7ab949..e2da5adef 100644
--- a/backend/src/api/liquid/elements-parser.ts
+++ b/backend/src/api/liquid/elements-parser.ts
@@ -33,10 +33,8 @@ class ElementsParser {
   }
 
   public async $getPegDataByMonth(): Promise<any> {
-    const connection = await DB.getConnection();
     const query = `SELECT SUM(amount) AS amount, DATE_FORMAT(FROM_UNIXTIME(datetime), '%Y-%m-01') AS date FROM elements_pegs GROUP BY DATE_FORMAT(FROM_UNIXTIME(datetime), '%Y%m')`;
-    const [rows] = await connection.query<any>(query);
-    connection.release();
+    const [rows] = await DB.query(query);
     return rows;
   }
 
@@ -79,7 +77,6 @@ class ElementsParser {
 
   protected async $savePegToDatabase(height: number, blockTime: number, amount: number, txid: string,
     txindex: number, bitcoinaddress: string, bitcointxid: string, bitcoinindex: number, final_tx: number): Promise<void> {
-    const connection = await DB.getConnection();
     const query = `INSERT INTO elements_pegs(
         block, datetime, amount, txid, txindex, bitcoinaddress, bitcointxid, bitcoinindex, final_tx
       ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)`;
@@ -87,24 +84,19 @@ class ElementsParser {
     const params: (string | number)[] = [
       height, blockTime, amount, txid, txindex, bitcoinaddress, bitcointxid, bitcoinindex, final_tx
     ];
-    await connection.query(query, params);
-    connection.release();
+    await DB.query(query, params);
     logger.debug(`Saved L-BTC peg from block height #${height} with TXID ${txid}.`);
   }
 
   protected async $getLatestBlockHeightFromDatabase(): Promise<number> {
-    const connection = await DB.getConnection();
     const query = `SELECT number FROM state WHERE name = 'last_elements_block'`;
-    const [rows] = await connection.query<any>(query);
-    connection.release();
+    const [rows] = await DB.query(query);
     return rows[0]['number'];
   }
 
   protected async $saveLatestBlockToDatabase(blockHeight: number) {
-    const connection = await DB.getConnection();
     const query = `UPDATE state SET number = ? WHERE name = 'last_elements_block'`;
-    await connection.query<any>(query, [blockHeight]);
-    connection.release();
+    await DB.query(query, [blockHeight]);
   }
 }
 
diff --git a/backend/src/api/pools-parser.ts b/backend/src/api/pools-parser.ts
index fc379cc8c..d53335c9f 100644
--- a/backend/src/api/pools-parser.ts
+++ b/backend/src/api/pools-parser.ts
@@ -59,13 +59,11 @@ class PoolsParser {
     logger.debug(`Found ${poolNames.length} unique mining pools`);
 
     // Get existing pools from the db
-    const connection = await DB.getConnection();
     let existingPools;
     try {
-      [existingPools] = await connection.query<any>({ sql: 'SELECT * FROM pools;', timeout: 120000 });
+      [existingPools] = await DB.query({ sql: 'SELECT * FROM pools;', timeout: 120000 });
     } catch (e) {
       logger.err('Cannot get existing pools from the database, skipping pools.json import');
-      connection.release();
       return;
     }
 
@@ -145,17 +143,15 @@ class PoolsParser {
 
     try {
       if (finalPoolDataAdd.length > 0) {
-        await connection.query<any>({ sql: queryAdd, timeout: 120000 });
+        await DB.query({ sql: queryAdd, timeout: 120000 });
       }
       for (const query of updateQueries) {
-        await connection.query<any>({ sql: query, timeout: 120000 });
+        await DB.query({ sql: query, timeout: 120000 });
       }
       await this.insertUnknownPool();
-      connection.release();
       logger.info('Mining pools.json import completed');
     } catch (e) {
-      connection.release();
-      logger.err(`Unable to import pools in the database`);
+      logger.err(`Cannot import pools in the database`);
       throw e;
     }
   }
@@ -164,16 +160,15 @@ class PoolsParser {
    * Manually add the 'unknown pool'
    */
   private async insertUnknownPool() {
-    const connection = await DB.getConnection();
     try {
-      const [rows]: any[] = await connection.query({ sql: 'SELECT name from pools where name="Unknown"', timeout: 120000 });
+      const [rows]: any[] = await DB.query({ sql: 'SELECT name from pools where name="Unknown"', timeout: 120000 });
       if (rows.length === 0) {
-        await connection.query({
+        await DB.query({
           sql: `INSERT INTO pools(name, link, regexes, addresses, slug)
           VALUES("Unknown", "https://learnmeabitcoin.com/technical/coinbase-transaction", "[]", "[]", "unknown");
         `});
       } else {
-        await connection.query(`UPDATE pools
+        await DB.query(`UPDATE pools
           SET name='Unknown', link='https://learnmeabitcoin.com/technical/coinbase-transaction',
           regexes='[]', addresses='[]',
           slug='unknown'
@@ -183,8 +178,6 @@ class PoolsParser {
     } catch (e) {
       logger.err('Unable to insert "Unknown" mining pool');
     }
-
-    connection.release();
   }
 }
 
diff --git a/backend/src/api/statistics.ts b/backend/src/api/statistics.ts
index 3d99adcb7..d5690c52e 100644
--- a/backend/src/api/statistics.ts
+++ b/backend/src/api/statistics.ts
@@ -155,7 +155,6 @@ class Statistics {
   }
 
   private async $createZeroedStatistic(): Promise<number | undefined> {
-    const connection = await DB.getConnection();
     try {
       const query = `INSERT INTO statistics(
               added,
@@ -206,17 +205,14 @@ class Statistics {
             )
             VALUES (NOW(), 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)`;
-      const [result]: any = await connection.query(query);
-      connection.release();
+      const [result]: any = await DB.query(query);
       return result.insertId;
     } catch (e) {
-      connection.release();
       logger.err('$create() error' + (e instanceof Error ? e.message : e));
     }
   }
 
   private async $create(statistics: Statistic): Promise<number | undefined> {
-    const connection = await DB.getConnection();
     try {
       const query = `INSERT INTO statistics(
               added,
@@ -314,11 +310,9 @@ class Statistics {
         statistics.vsize_1800,
         statistics.vsize_2000,
       ];
-      const [result]: any = await connection.query(query, params);
-      connection.release();
+      const [result]: any = await DB.query(query, params);
       return result.insertId;
     } catch (e) {
-      connection.release();
       logger.err('$create() error' + (e instanceof Error ? e.message : e));
     }
   }
@@ -421,10 +415,8 @@ class Statistics {
 
   private async $get(id: number): Promise<OptimizedStatistic | undefined> {
     try {
-      const connection = await DB.getConnection();
       const query = `SELECT *, UNIX_TIMESTAMP(added) as added FROM statistics WHERE id = ?`;
-      const [rows] = await connection.query<any>(query, [id]);
-      connection.release();
+      const [rows] = await DB.query(query, [id]);
       if (rows[0]) {
         return this.mapStatisticToOptimizedStatistic([rows[0]])[0];
       }
@@ -435,11 +427,9 @@ class Statistics {
 
   public async $list2H(): Promise<OptimizedStatistic[]> {
     try {
-      const connection = await DB.getConnection();
       const query = `SELECT *, UNIX_TIMESTAMP(added) as added FROM statistics ORDER BY statistics.added DESC LIMIT 120`;
-      const [rows] = await connection.query<any>({ sql: query, timeout: this.queryTimeout });
-      connection.release();
-      return this.mapStatisticToOptimizedStatistic(rows);
+      const [rows] = await DB.query({ sql: query, timeout: this.queryTimeout });
+      return this.mapStatisticToOptimizedStatistic(rows as Statistic[]);
     } catch (e) {
       logger.err('$list2H() error' + (e instanceof Error ? e.message : e));
       return [];
@@ -448,11 +438,9 @@ class Statistics {
 
   public async $list24H(): Promise<OptimizedStatistic[]> {
     try {
-      const connection = await DB.getConnection();
       const query = `SELECT *, UNIX_TIMESTAMP(added) as added FROM statistics ORDER BY statistics.added DESC LIMIT 1440`;
-      const [rows] = await connection.query<any>({ sql: query, timeout: this.queryTimeout });
-      connection.release();
-      return this.mapStatisticToOptimizedStatistic(rows);
+      const [rows] = await DB.query({ sql: query, timeout: this.queryTimeout });
+      return this.mapStatisticToOptimizedStatistic(rows as Statistic[]);
     } catch (e) {
       logger.err('$list24h() error' + (e instanceof Error ? e.message : e));
       return [];
@@ -461,11 +449,9 @@ class Statistics {
 
   public async $list1W(): Promise<OptimizedStatistic[]> {
     try {
-      const connection = await DB.getConnection();
       const query = this.getQueryForDaysAvg(300, '1 WEEK'); // 5m interval
-      const [rows] = await connection.query<any>({ sql: query, timeout: this.queryTimeout });
-      connection.release();
-      return this.mapStatisticToOptimizedStatistic(rows);
+      const [rows] = await DB.query({ sql: query, timeout: this.queryTimeout });
+      return this.mapStatisticToOptimizedStatistic(rows as Statistic[]);
     } catch (e) {
       logger.err('$list1W() error' + (e instanceof Error ? e.message : e));
       return [];
@@ -474,11 +460,9 @@ class Statistics {
 
   public async $list1M(): Promise<OptimizedStatistic[]> {
     try {
-      const connection = await DB.getConnection();
       const query = this.getQueryForDaysAvg(1800, '1 MONTH'); // 30m interval
-      const [rows] = await connection.query<any>({ sql: query, timeout: this.queryTimeout });
-      connection.release();
-      return this.mapStatisticToOptimizedStatistic(rows);
+      const [rows] = await DB.query({ sql: query, timeout: this.queryTimeout });
+      return this.mapStatisticToOptimizedStatistic(rows as Statistic[]);
     } catch (e) {
       logger.err('$list1M() error' + (e instanceof Error ? e.message : e));
       return [];
@@ -487,11 +471,9 @@ class Statistics {
 
   public async $list3M(): Promise<OptimizedStatistic[]> {
     try {
-      const connection = await DB.getConnection();
       const query = this.getQueryForDaysAvg(7200, '3 MONTH'); // 2h interval
-      const [rows] = await connection.query<any>({ sql: query, timeout: this.queryTimeout });
-      connection.release();
-      return this.mapStatisticToOptimizedStatistic(rows);
+      const [rows] = await DB.query({ sql: query, timeout: this.queryTimeout });
+      return this.mapStatisticToOptimizedStatistic(rows as Statistic[]);
     } catch (e) {
       logger.err('$list3M() error' + (e instanceof Error ? e.message : e));
       return [];
@@ -500,11 +482,9 @@ class Statistics {
 
   public async $list6M(): Promise<OptimizedStatistic[]> {
     try {
-      const connection = await DB.getConnection();
-      const query = this.getQueryForDaysAvg(10800, '6 MONTH'); // 3h interval 
-      const [rows] = await connection.query<any>({ sql: query, timeout: this.queryTimeout });
-      connection.release();
-      return this.mapStatisticToOptimizedStatistic(rows);
+      const query = this.getQueryForDaysAvg(10800, '6 MONTH'); // 3h interval
+      const [rows] = await DB.query({ sql: query, timeout: this.queryTimeout });
+      return this.mapStatisticToOptimizedStatistic(rows as Statistic[]);
     } catch (e) {
       logger.err('$list6M() error' + (e instanceof Error ? e.message : e));
       return [];
@@ -513,11 +493,9 @@ class Statistics {
 
   public async $list1Y(): Promise<OptimizedStatistic[]> {
     try {
-      const connection = await DB.getConnection();
       const query = this.getQueryForDays(28800, '1 YEAR'); // 8h interval
-      const [rows] = await connection.query<any>({ sql: query, timeout: this.queryTimeout });
-      connection.release();
-      return this.mapStatisticToOptimizedStatistic(rows);
+      const [rows] = await DB.query({ sql: query, timeout: this.queryTimeout });
+      return this.mapStatisticToOptimizedStatistic(rows as Statistic[]);
     } catch (e) {
       logger.err('$list1Y() error' + (e instanceof Error ? e.message : e));
       return [];
@@ -526,11 +504,9 @@ class Statistics {
 
   public async $list2Y(): Promise<OptimizedStatistic[]> {
     try {
-      const connection = await DB.getConnection();
-      const query = this.getQueryForDays(28800, "2 YEAR"); // 8h interval
-      const [rows] = await connection.query<any>({ sql: query, timeout: this.queryTimeout });
-      connection.release();
-      return this.mapStatisticToOptimizedStatistic(rows);
+      const query = this.getQueryForDays(28800, '2 YEAR'); // 8h interval
+      const [rows] = await DB.query({ sql: query, timeout: this.queryTimeout });
+      return this.mapStatisticToOptimizedStatistic(rows as Statistic[]);
     } catch (e) {
       logger.err('$list2Y() error' + (e instanceof Error ? e.message : e));
       return [];
@@ -539,11 +515,9 @@ class Statistics {
 
   public async $list3Y(): Promise<OptimizedStatistic[]> {
     try {
-      const connection = await DB.getConnection();
-      const query = this.getQueryForDays(43200, "3 YEAR"); // 12h interval
-      const [rows] = await connection.query<any>({ sql: query, timeout: this.queryTimeout });
-      connection.release();
-      return this.mapStatisticToOptimizedStatistic(rows);
+      const query = this.getQueryForDays(43200, '3 YEAR'); // 12h interval
+      const [rows] = await DB.query({ sql: query, timeout: this.queryTimeout });
+      return this.mapStatisticToOptimizedStatistic(rows as Statistic[]);
     } catch (e) {
       logger.err('$list3Y() error' + (e instanceof Error ? e.message : e));
       return [];
diff --git a/backend/src/database.ts b/backend/src/database.ts
index 55be0ffc3..3ccad9aa3 100644
--- a/backend/src/database.ts
+++ b/backend/src/database.ts
@@ -1,11 +1,14 @@
 import config from './config';
-import { createPool, PoolConnection } from 'mysql2/promise';
+import { createPool, Pool, PoolConnection } from 'mysql2/promise';
 import logger from './logger';
 import { PoolOptions } from 'mysql2/typings/mysql';
 
 export class DB {
-  static poolConfig = ():PoolOptions => {
-    let poolConfig:PoolOptions = {
+  static connectionsReady: number[] = [];
+  static pool: Pool | null = null;
+
+  static poolConfig = (): PoolOptions => {
+    const poolConfig: PoolOptions = {
       port: config.DATABASE.PORT,
       database: config.DATABASE.DATABASE,
       user: config.DATABASE.USERNAME,
@@ -13,9 +16,9 @@ export class DB {
       connectionLimit: 10,
       supportBigNumbers: true,
       timezone: '+00:00',
-    }
+    };
 
-    if (config.DATABASE.SOCKET !== "") {
+    if (config.DATABASE.SOCKET !== '') {
       poolConfig.socketPath = config.DATABASE.SOCKET;
     } else {
       poolConfig.host = config.DATABASE.HOST;
@@ -23,27 +26,27 @@ export class DB {
 
     return poolConfig;
   }
-  
-  static pool = createPool(DB.poolConfig());
 
-  static connectionsReady: number[] = [];
-
-  static async getConnection() {
-    const connection: PoolConnection = await DB.pool.getConnection();
-    const connectionId = connection['connection'].connectionId;
-    if (!DB.connectionsReady.includes(connectionId)) {
-      await connection.query(`SET time_zone='+00:00';`);
-      this.connectionsReady.push(connectionId);
+  static async getPool(): Promise<Pool> {
+    if (DB.pool === null) {
+      DB.pool = createPool(DB.poolConfig());
+      DB.pool.on('connection', function (newConnection: PoolConnection) {
+        newConnection.query(`SET time_zone='+00:00'`);
+      });
     }
-    return connection;
+    return DB.pool;
+  }
+
+  static async query(query, params?) {
+    const pool = await DB.getPool();
+    return pool.query(query, params);
   }
 }
 
 export async function checkDbConnection() {
   try {
-    const connection = await DB.getConnection();
+    await DB.query('SELECT ?', [1]);
     logger.info('Database connection established.');
-    connection.release();
   } catch (e) {
     logger.err('Could not connect to database: ' + (e instanceof Error ? e.message : e));
     process.exit(1);
diff --git a/backend/src/index.ts b/backend/src/index.ts
index cd8d55757..1081c5468 100644
--- a/backend/src/index.ts
+++ b/backend/src/index.ts
@@ -188,7 +188,7 @@ class Server {
         await BlocksRepository.$deleteBlocks(10);
         await HashratesRepository.$deleteLastEntries();
       }
-      blocks.$generateBlockDatabase();
+      await blocks.$generateBlockDatabase();
       await mining.$generateNetworkHashrateHistory();
       await mining.$generatePoolHashrateHistory();
     } catch (e) {
diff --git a/backend/src/repositories/BlocksRepository.ts b/backend/src/repositories/BlocksRepository.ts
index d5decfcaa..e35647fd2 100644
--- a/backend/src/repositories/BlocksRepository.ts
+++ b/backend/src/repositories/BlocksRepository.ts
@@ -10,11 +10,7 @@ class BlocksRepository {
    * Save indexed block data in the database
    */
   public async $saveBlockInDatabase(block: BlockExtended) {
-    let connection;
-
     try {
-      connection = await DB.getConnection();
-
       const query = `INSERT INTO blocks(
         height,           hash,                blockTimestamp, size,
         weight,           tx_count,            coinbase_raw,   difficulty,
@@ -52,14 +48,11 @@ class BlocksRepository {
         block.extras.avgFeeRate,
       ];
 
-      await connection.query(query, params);
-      connection.release();
+      await DB.query(query, params);
     } catch (e: any) {
-      connection.release();
       if (e.errno === 1062) { // ER_DUP_ENTRY - This scenario is possible upon node backend restart
         logger.debug(`$saveBlockInDatabase() - Block ${block.height} has already been indexed, ignoring`);
       } else {
-        connection.release();
         logger.err('Cannot save indexed block into db. Reason: ' + (e instanceof Error ? e.message : e));
         throw e;
       }
@@ -74,16 +67,13 @@ class BlocksRepository {
       return [];
     }
 
-    let connection;
     try {
-      connection = await DB.getConnection();
-      const [rows]: any[] = await connection.query(`
+      const [rows]: any[] = await DB.query(`
         SELECT height
         FROM blocks
         WHERE height <= ? AND height >= ?
         ORDER BY height DESC;
       `, [startHeight, endHeight]);
-      connection.release();
 
       const indexedBlockHeights: number[] = [];
       rows.forEach((row: any) => { indexedBlockHeights.push(row.height); });
@@ -92,7 +82,6 @@ class BlocksRepository {
 
       return missingBlocksHeights;
     } catch (e) {
-      connection.release();
       logger.err('Cannot retrieve blocks list to index. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -121,15 +110,10 @@ class BlocksRepository {
 
     query += ` GROUP by pools.id`;
 
-    let connection;
     try {
-      connection = await DB.getConnection();
-      const [rows] = await connection.query(query, params);
-      connection.release();
-
+      const [rows] = await DB.query(query, params);
       return rows;
     } catch (e) {
-      connection.release();
       logger.err('Cannot count empty blocks. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -159,15 +143,10 @@ class BlocksRepository {
       query += ` blockTimestamp BETWEEN DATE_SUB(NOW(), INTERVAL ${interval}) AND NOW()`;
     }
 
-    let connection;
     try {
-      connection = await DB.getConnection();
-      const [rows] = await connection.query(query, params);
-      connection.release();
-
+      const [rows] = await DB.query(query, params);
       return <number>rows[0].blockCount;
     } catch (e) {
-      connection.release();
       logger.err(`Cannot count blocks for this pool (using offset). Reason: ` + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -199,15 +178,10 @@ class BlocksRepository {
     }
     query += ` blockTimestamp BETWEEN FROM_UNIXTIME('${from}') AND FROM_UNIXTIME('${to}')`;
 
-    let connection;
     try {
-      connection = await DB.getConnection();
-      const [rows] = await connection.query(query, params);
-      connection.release();
-
+      const [rows] = await DB.query(query, params);
       return <number>rows[0];
     } catch (e) {
-      connection.release();
       logger.err(`Cannot count blocks for this pool (using timestamps). Reason: ` + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -222,11 +196,8 @@ class BlocksRepository {
       ORDER BY height
       LIMIT 1;`;
 
-    let connection;
     try {
-      connection = await DB.getConnection();
-      const [rows]: any[] = await connection.query(query);
-      connection.release();
+      const [rows]: any[] = await DB.query(query);
 
       if (rows.length <= 0) {
         return -1;
@@ -234,7 +205,6 @@ class BlocksRepository {
 
       return <number>rows[0].blockTimestamp;
     } catch (e) {
-      connection.release();
       logger.err('Cannot get oldest indexed block timestamp. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -243,7 +213,7 @@ class BlocksRepository {
   /**
    * Get blocks mined by a specific mining pool
    */
-  public async $getBlocksByPool(slug: string, startHeight: number | undefined = undefined): Promise<object[]> {
+  public async $getBlocksByPool(slug: string, startHeight?: number): Promise<object[]> {
     const pool = await PoolsRepository.$getPool(slug);
     if (!pool) {
       throw new Error(`This mining pool does not exist`);
@@ -264,20 +234,16 @@ class BlocksRepository {
     query += ` ORDER BY height DESC
       LIMIT 10`;
 
-    let connection;
     try {
-      connection = await DB.getConnection();
-      const [rows] = await connection.query(query, params);
-      connection.release();
+      const [rows] = await DB.query(query, params);
 
       const blocks: BlockExtended[] = [];
-      for (let block of <object[]>rows) {
+      for (const block of <object[]>rows) {
         blocks.push(prepareBlock(block));
       }
 
       return blocks;
     } catch (e) {
-      connection.release();
       logger.err('Cannot get blocks for this pool. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -287,10 +253,8 @@ class BlocksRepository {
    * Get one block by height
    */
   public async $getBlockByHeight(height: number): Promise<object | null> {
-    let connection;
     try {
-      connection = await DB.getConnection();
-      const [rows]: any[] = await connection.query(`
+      const [rows]: any[] = await DB.query(`
         SELECT *, UNIX_TIMESTAMP(blocks.blockTimestamp) as blockTimestamp,
         pools.id as pool_id, pools.name as pool_name, pools.link as pool_link, pools.slug as pool_slug,
         pools.addresses as pool_addresses, pools.regexes as pool_regexes,
@@ -299,7 +263,6 @@ class BlocksRepository {
         JOIN pools ON blocks.pool_id = pools.id
         WHERE height = ${height};
       `);
-      connection.release();
 
       if (rows.length <= 0) {
         return null;
@@ -307,7 +270,6 @@ class BlocksRepository {
 
       return rows[0];
     } catch (e) {
-      connection.release();
       logger.err(`Cannot get indexed block ${height}. Reason: ` + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -351,20 +313,15 @@ class BlocksRepository {
       ORDER BY t.height
     `;
 
-    let connection;
     try {
-      connection = await DB.getConnection();
-      const [rows]: any[] = await connection.query(query);
-      connection.release();
+      const [rows]: any[] = await DB.query(query);
 
       for (const row of rows) {
         delete row['rn'];
       }
 
-      connection.release();
       return rows;
     } catch (e) {
-      connection.release();
       logger.err('Cannot generate difficulty history. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -374,10 +331,7 @@ class BlocksRepository {
    * Get general block stats
    */
   public async $getBlockStats(blockCount: number): Promise<any> {
-    let connection;
     try {
-      connection = await DB.getConnection();
-
       // We need to use a subquery
       const query = `
         SELECT MIN(height) as startBlock, MAX(height) as endBlock, SUM(reward) as totalReward, SUM(fees) as totalFee, SUM(tx_count) as totalTx
@@ -386,12 +340,10 @@ class BlocksRepository {
           ORDER by height DESC
           LIMIT ?) as sub`;
 
-      const [rows]: any = await connection.query(query, [blockCount]);
-      connection.release();
- 
+      const [rows]: any = await DB.query(query, [blockCount]);
+
       return rows[0];
     } catch (e) {
-      connection.release();
       logger.err('Cannot generate reward stats. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -401,12 +353,8 @@ class BlocksRepository {
    * Check if the last 10 blocks chain is valid
    */
   public async $validateRecentBlocks(): Promise<boolean> {
-    let connection;
-
     try {
-      connection = await DB.getConnection();
-      const [lastBlocks] = await connection.query(`SELECT height, hash, previous_block_hash FROM blocks ORDER BY height DESC LIMIT 10`);
-      connection.release();
+      const [lastBlocks]: any[] = await DB.query(`SELECT height, hash, previous_block_hash FROM blocks ORDER BY height DESC LIMIT 10`);
 
       for (let i = 0; i < lastBlocks.length - 1; ++i) {
         if (lastBlocks[i].previous_block_hash !== lastBlocks[i + 1].hash) {
@@ -417,8 +365,6 @@ class BlocksRepository {
 
       return true;
     } catch (e) {
-      connection.release();
-
       return true; // Don't do anything if there is a db error
     }
   }
@@ -428,26 +374,19 @@ class BlocksRepository {
    */
   public async $deleteBlocks(count: number) {
     logger.info(`Delete ${count} most recent indexed blocks from the database`);
-    let connection;
 
     try {
-      connection = await DB.getConnection();
-      await connection.query(`DELETE FROM blocks ORDER BY height DESC LIMIT ${count};`);
+      await DB.query(`DELETE FROM blocks ORDER BY height DESC LIMIT ${count};`);
     } catch (e) {
       logger.err('Cannot delete recent indexed blocks. Reason: ' + (e instanceof Error ? e.message : e));
     }
-
-    connection.release();
   }
 
   /**
    * Get the historical averaged block fees
    */
   public async $getHistoricalBlockFees(div: number, interval: string | null): Promise<any> {
-    let connection;
     try {
-      connection = await DB.getConnection();
-
       let query = `SELECT CAST(AVG(UNIX_TIMESTAMP(blockTimestamp)) as INT) as timestamp,
         CAST(AVG(fees) as INT) as avg_fees
         FROM blocks`;
@@ -458,12 +397,9 @@ class BlocksRepository {
 
       query += ` GROUP BY UNIX_TIMESTAMP(blockTimestamp) DIV ${div}`;
 
-      const [rows]: any = await connection.query(query);
-      connection.release();
-
+      const [rows]: any = await DB.query(query);
       return rows;
     } catch (e) {
-      connection.release();
       logger.err('Cannot generate block fees history. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -473,10 +409,7 @@ class BlocksRepository {
    * Get the historical averaged block rewards
    */
    public async $getHistoricalBlockRewards(div: number, interval: string | null): Promise<any> {
-    let connection;
     try {
-      connection = await DB.getConnection();
-
       let query = `SELECT CAST(AVG(UNIX_TIMESTAMP(blockTimestamp)) as INT) as timestamp,
         CAST(AVG(reward) as INT) as avg_rewards
         FROM blocks`;
@@ -487,12 +420,9 @@ class BlocksRepository {
 
       query += ` GROUP BY UNIX_TIMESTAMP(blockTimestamp) DIV ${div}`;
 
-      const [rows]: any = await connection.query(query);
-      connection.release();
-
+      const [rows]: any = await DB.query(query);
       return rows;
     } catch (e) {
-      connection.release();
       logger.err('Cannot generate block rewards history. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
diff --git a/backend/src/repositories/HashratesRepository.ts b/backend/src/repositories/HashratesRepository.ts
index e63fe5ddb..1701d2236 100644
--- a/backend/src/repositories/HashratesRepository.ts
+++ b/backend/src/repositories/HashratesRepository.ts
@@ -20,13 +20,9 @@ class HashratesRepository {
     }
     query = query.slice(0, -1);
 
-    let connection;
     try {
-      connection = await DB.getConnection();
-      await connection.query(query);
-      connection.release();
+      await DB.query(query);
     } catch (e: any) {
-      connection.release();
       logger.err('Cannot save indexed hashrate into db. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -35,8 +31,6 @@ class HashratesRepository {
   public async $getNetworkDailyHashrate(interval: string | null): Promise<any[]> {
     interval = Common.getSqlInterval(interval);
 
-    const connection = await DB.getConnection();
-
     let query = `SELECT UNIX_TIMESTAMP(hashrate_timestamp) as timestamp, avg_hashrate as avgHashrate
       FROM hashrates`;
 
@@ -50,32 +44,24 @@ class HashratesRepository {
     query += ` ORDER by hashrate_timestamp`;
 
     try {
-      const [rows]: any[] = await connection.query(query);
-      connection.release();
-
+      const [rows]: any[] = await DB.query(query);
       return rows;
     } catch (e) {
-      connection.release();
       logger.err('Cannot fetch network hashrate history. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
   }
 
   public async $getWeeklyHashrateTimestamps(): Promise<number[]> {
-    const connection = await DB.getConnection();
-
     const query = `SELECT UNIX_TIMESTAMP(hashrate_timestamp) as timestamp
       FROM hashrates
       WHERE type = 'weekly'
       GROUP BY hashrate_timestamp`;
 
     try {
-      const [rows]: any[] = await connection.query(query);
-      connection.release();
-
+      const [rows]: any[] = await DB.query(query);
       return rows.map(row => row.timestamp);
     } catch (e) {
-      connection.release();
       logger.err('Cannot retreive indexed weekly hashrate timestamps. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -87,7 +73,6 @@ class HashratesRepository {
   public async $getPoolsWeeklyHashrate(interval: string | null): Promise<any[]> {
     interval = Common.getSqlInterval(interval);
 
-    const connection = await DB.getConnection();
     const topPoolsId = (await PoolsRepository.$getPoolsInfo('1w')).map((pool) => pool.poolId);
 
     let query = `SELECT UNIX_TIMESTAMP(hashrate_timestamp) as timestamp, avg_hashrate as avgHashrate, share, pools.name as poolName
@@ -106,12 +91,9 @@ class HashratesRepository {
     query += ` ORDER by hashrate_timestamp, FIELD(pool_id, ${topPoolsId})`;
 
     try {
-      const [rows]: any[] = await connection.query(query);
-      connection.release();
-
+      const [rows]: any[] = await DB.query(query);
       return rows;
     } catch (e) {
-      connection.release();
       logger.err('Cannot fetch weekly pools hashrate history. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -128,8 +110,8 @@ class HashratesRepository {
 
     // Find hashrate boundaries
     let query = `SELECT MIN(hashrate_timestamp) as firstTimestamp, MAX(hashrate_timestamp) as lastTimestamp
-      FROM hashrates 
-      JOIN pools on pools.id = pool_id 
+      FROM hashrates
+      JOIN pools on pools.id = pool_id
       WHERE hashrates.type = 'weekly' AND pool_id = ? AND avg_hashrate != 0
       ORDER by hashrate_timestamp LIMIT 1`;
 
@@ -138,14 +120,10 @@ class HashratesRepository {
       lastTimestamp: '9999-01-01'
     };
 
-    let connection;
     try {
-      connection = await DB.getConnection();
-      const [rows]: any[] = await connection.query(query, [pool.id]);
+      const [rows]: any[] = await DB.query(query, [pool.id]);
       boundaries = rows[0];
-      connection.release();
     } catch (e) {
-      connection.release();
       logger.err('Cannot fetch hashrate start/end timestamps for this pool. Reason: ' + (e instanceof Error ? e.message : e));
     }
 
@@ -158,12 +136,9 @@ class HashratesRepository {
       ORDER by hashrate_timestamp`;
 
     try {
-      const [rows]: any[] = await connection.query(query, [boundaries.firstTimestamp, boundaries.lastTimestamp, pool.id]);
-      connection.release();
-
+      const [rows]: any[] = await DB.query(query, [boundaries.firstTimestamp, boundaries.lastTimestamp, pool.id]);
       return rows;
     } catch (e) {
-      connection.release();
       logger.err('Cannot fetch pool hashrate history for this pool. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -173,14 +148,11 @@ class HashratesRepository {
    * Set latest run timestamp
    */
   public async $setLatestRunTimestamp(key: string, val: any = null) {
-    const connection = await DB.getConnection();
     const query = `UPDATE state SET number = ? WHERE name = ?`;
 
     try {
-      await connection.query<any>(query, (val === null) ? [Math.round(new Date().getTime() / 1000), key] : [val, key]);
-      connection.release();
+      await DB.query(query, (val === null) ? [Math.round(new Date().getTime() / 1000), key] : [val, key]);
     } catch (e) {
-      connection.release();
       logger.err(`Cannot set last indexing timestamp for ${key}. Reason: ` + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -190,19 +162,16 @@ class HashratesRepository {
    * Get latest run timestamp
    */
   public async $getLatestRunTimestamp(key: string): Promise<number> {
-    const connection = await DB.getConnection();
     const query = `SELECT number FROM state WHERE name = ?`;
 
     try {
-      const [rows] = await connection.query<any>(query, [key]);
-      connection.release();
+      const [rows]: any[] = await DB.query(query, [key]);
 
       if (rows.length === 0) {
         return 0;
       }
       return rows[0]['number'];
     } catch (e) {
-      connection.release();
       logger.err(`Cannot retreive last indexing timestamp for ${key}. Reason: ` + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -214,12 +183,10 @@ class HashratesRepository {
   public async $deleteLastEntries() {
     logger.info(`Delete latest hashrates data points from the database`);
 
-    let connection;
     try {
-      connection = await DB.getConnection();
-      const [rows] = await connection.query(`SELECT MAX(hashrate_timestamp) as timestamp FROM hashrates GROUP BY type`);
+      const [rows]: any[] = await DB.query(`SELECT MAX(hashrate_timestamp) as timestamp FROM hashrates GROUP BY type`);
       for (const row of rows) {
-        await connection.query(`DELETE FROM hashrates WHERE hashrate_timestamp = ?`, [row.timestamp]);
+        await DB.query(`DELETE FROM hashrates WHERE hashrate_timestamp = ?`, [row.timestamp]);
       }
       // Re-run the hashrate indexing to fill up missing data
       await this.$setLatestRunTimestamp('last_hashrates_indexing', 0);
@@ -227,8 +194,6 @@ class HashratesRepository {
     } catch (e) {
       logger.err('Cannot delete latest hashrates data points. Reason: ' + (e instanceof Error ? e.message : e));
     }
-
-    connection.release();
   }
 }
 
diff --git a/backend/src/repositories/PoolsRepository.ts b/backend/src/repositories/PoolsRepository.ts
index 9d609f761..c1f8cc80f 100644
--- a/backend/src/repositories/PoolsRepository.ts
+++ b/backend/src/repositories/PoolsRepository.ts
@@ -9,9 +9,7 @@ class PoolsRepository {
    * Get all pools tagging info
    */
   public async $getPools(): Promise<PoolTag[]> {
-    const connection = await DB.getConnection();
-    const [rows] = await connection.query('SELECT id, name, addresses, regexes, slug FROM pools;');
-    connection.release();
+    const [rows] = await DB.query('SELECT id, name, addresses, regexes, slug FROM pools;');
     return <PoolTag[]>rows;
   }
 
@@ -19,9 +17,7 @@ class PoolsRepository {
    * Get unknown pool tagging info
    */
   public async $getUnknownPool(): Promise<PoolTag> {
-    const connection = await DB.getConnection();
-    const [rows] = await connection.query('SELECT id, name, slug FROM pools where name = "Unknown"');
-    connection.release();
+    const [rows] = await DB.query('SELECT id, name, slug FROM pools where name = "Unknown"');
     return <PoolTag>rows[0];
   }
 
@@ -42,14 +38,10 @@ class PoolsRepository {
     query += ` GROUP BY pool_id
       ORDER BY COUNT(height) DESC`;
 
-    const connection = await DB.getConnection();
     try {
-      const [rows] = await connection.query(query);
-      connection.release();
-
+      const [rows] = await DB.query(query);
       return <PoolInfo[]>rows;
     } catch (e) {
-      connection.release();
       logger.err(`Cannot generate pools stats. Reason: ` + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -64,14 +56,10 @@ class PoolsRepository {
       LEFT JOIN blocks on pools.id = blocks.pool_id AND blocks.blockTimestamp BETWEEN FROM_UNIXTIME(?) AND FROM_UNIXTIME(?)
       GROUP BY pools.id`;
 
-    const connection = await DB.getConnection();
     try {
-      const [rows] = await connection.query(query, [from, to]);
-      connection.release();
-
+      const [rows] = await DB.query(query, [from, to]);
       return <PoolInfo[]>rows;
     } catch (e) {
-      connection.release();
       logger.err('Cannot generate pools blocks count. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
@@ -86,12 +74,8 @@ class PoolsRepository {
       FROM pools
       WHERE pools.slug = ?`;
 
-    let connection;
     try {
-      connection = await DB.getConnection();
-
-      const [rows] = await connection.query(query, [slug]);
-      connection.release();
+      const [rows]: any[] = await DB.query(query, [slug]);
 
       if (rows.length < 1) {
         logger.debug(`This slug does not match any known pool`);
@@ -107,7 +91,6 @@ class PoolsRepository {
 
       return rows[0];
     } catch (e) {
-      connection.release();
       logger.err('Cannot get pool from db. Reason: ' + (e instanceof Error ? e.message : e));
       throw e;
     }
diff --git a/backend/src/tasks/pools-updater.ts b/backend/src/tasks/pools-updater.ts
index 22c2b16b0..90937a16f 100644
--- a/backend/src/tasks/pools-updater.ts
+++ b/backend/src/tasks/pools-updater.ts
@@ -1,8 +1,8 @@
 const https = require('https');
-import poolsParser from "../api/pools-parser";
-import config from "../config";
-import { DB } from "../database";
-import logger from "../logger";
+import poolsParser from '../api/pools-parser';
+import config from '../config';
+import { DB } from '../database';
+import logger from '../logger';
 
 /**
  * Maintain the most recent version of pools.json
@@ -64,15 +64,11 @@ class PoolsUpdater {
    * Fetch our latest pools.json sha from the db
    */
   private async updateDBSha(githubSha: string) {
-    let connection;
     try {
-      connection = await DB.getConnection();
-      await connection.query('DELETE FROM state where name="pools_json_sha"');
-      await connection.query(`INSERT INTO state VALUES('pools_json_sha', NULL, '${githubSha}')`);
-      connection.release();
+      await DB.query('DELETE FROM state where name="pools_json_sha"');
+      await DB.query(`INSERT INTO state VALUES('pools_json_sha', NULL, '${githubSha}')`);
     } catch (e) {
       logger.err('Cannot save github pools.json sha into the db. Reason: '  + (e instanceof Error ? e.message : e));
-      connection.release();
       return undefined;
     }
   }
@@ -81,15 +77,11 @@ class PoolsUpdater {
    * Fetch our latest pools.json sha from the db
    */
   private async getShaFromDb(): Promise<string | undefined> {
-    let connection;
     try {
-      connection = await DB.getConnection();
-      const [rows] = await connection.query('SELECT string FROM state WHERE name="pools_json_sha"');
-      connection.release();
+      const [rows]: any[] = await DB.query('SELECT string FROM state WHERE name="pools_json_sha"');
       return (rows.length > 0 ? rows[0].string : undefined);
     } catch (e) {
       logger.err('Cannot fetch pools.json sha from db. Reason: '  + (e instanceof Error ? e.message : e));
-      connection.release();
       return undefined;
     }
   }
@@ -140,7 +132,7 @@ class PoolsUpdater {
       request.on('error', (error) => {
         logger.err('Github API query failed. Reason: '  + error);
         reject(error);
-      })
+      });
     });
   }
 }

From 6919393e6cea045bd1e8a8821324759a416f5b9b Mon Sep 17 00:00:00 2001
From: softsimon <softsimon@protonmail.com>
Date: Wed, 13 Apr 2022 17:38:42 +0400
Subject: [PATCH 17/17] Refactored the DB class into a regular singleton class.

---
 backend/src/api/database-migration.ts         |  2 +-
 backend/src/api/liquid/elements-parser.ts     |  2 +-
 backend/src/api/pools-parser.ts               |  3 +-
 backend/src/api/statistics.ts                 |  2 +-
 backend/src/database.ts                       | 71 +++++++++----------
 backend/src/index.ts                          |  4 +-
 backend/src/repositories/BlocksRepository.ts  |  4 +-
 .../src/repositories/HashratesRepository.ts   |  2 +-
 backend/src/repositories/PoolsRepository.ts   |  2 +-
 backend/src/tasks/pools-updater.ts            |  2 +-
 10 files changed, 45 insertions(+), 49 deletions(-)

diff --git a/backend/src/api/database-migration.ts b/backend/src/api/database-migration.ts
index ed93d695d..0e9a18220 100644
--- a/backend/src/api/database-migration.ts
+++ b/backend/src/api/database-migration.ts
@@ -1,5 +1,5 @@
 import config from '../config';
-import { DB } from '../database';
+import DB from '../database';
 import logger from '../logger';
 
 const sleep = (ms: number) => new Promise(res => setTimeout(res, ms));
diff --git a/backend/src/api/liquid/elements-parser.ts b/backend/src/api/liquid/elements-parser.ts
index e2da5adef..12439e037 100644
--- a/backend/src/api/liquid/elements-parser.ts
+++ b/backend/src/api/liquid/elements-parser.ts
@@ -2,7 +2,7 @@ import { IBitcoinApi } from '../bitcoin/bitcoin-api.interface';
 import bitcoinClient from '../bitcoin/bitcoin-client';
 import bitcoinSecondClient from '../bitcoin/bitcoin-second-client';
 import { Common } from '../common';
-import { DB } from '../../database';
+import DB from '../../database';
 import logger from '../../logger';
 
 class ElementsParser {
diff --git a/backend/src/api/pools-parser.ts b/backend/src/api/pools-parser.ts
index d53335c9f..202fca1bd 100644
--- a/backend/src/api/pools-parser.ts
+++ b/backend/src/api/pools-parser.ts
@@ -1,5 +1,4 @@
-import { readFileSync } from 'fs';
-import { DB } from '../database';
+import DB from '../database';
 import logger from '../logger';
 import config from '../config';
 
diff --git a/backend/src/api/statistics.ts b/backend/src/api/statistics.ts
index d5690c52e..bd93b4c6e 100644
--- a/backend/src/api/statistics.ts
+++ b/backend/src/api/statistics.ts
@@ -1,5 +1,5 @@
 import memPool from './mempool';
-import { DB } from '../database';
+import DB from '../database';
 import logger from '../logger';
 
 import { Statistic, TransactionExtended, OptimizedStatistic } from '../mempool.interfaces';
diff --git a/backend/src/database.ts b/backend/src/database.ts
index 3ccad9aa3..3816154cd 100644
--- a/backend/src/database.ts
+++ b/backend/src/database.ts
@@ -3,52 +3,49 @@ import { createPool, Pool, PoolConnection } from 'mysql2/promise';
 import logger from './logger';
 import { PoolOptions } from 'mysql2/typings/mysql';
 
-export class DB {
-  static connectionsReady: number[] = [];
-  static pool: Pool | null = null;
-
-  static poolConfig = (): PoolOptions => {
-    const poolConfig: PoolOptions = {
-      port: config.DATABASE.PORT,
-      database: config.DATABASE.DATABASE,
-      user: config.DATABASE.USERNAME,
-      password: config.DATABASE.PASSWORD,
-      connectionLimit: 10,
-      supportBigNumbers: true,
-      timezone: '+00:00',
-    };
-
+ class DB {
+  constructor() {
     if (config.DATABASE.SOCKET !== '') {
-      poolConfig.socketPath = config.DATABASE.SOCKET;
+      this.poolConfig.socketPath = config.DATABASE.SOCKET;
     } else {
-      poolConfig.host = config.DATABASE.HOST;
+      this.poolConfig.host = config.DATABASE.HOST;
     }
+  }
+  private pool: Pool | null = null;
+  private poolConfig: PoolOptions = {
+    port: config.DATABASE.PORT,
+    database: config.DATABASE.DATABASE,
+    user: config.DATABASE.USERNAME,
+    password: config.DATABASE.PASSWORD,
+    connectionLimit: 10,
+    supportBigNumbers: true,
+    timezone: '+00:00',
+  };
 
-    return poolConfig;
+  public async query(query, params?) {
+    const pool = await this.getPool();
+    return pool.query(query, params);
   }
 
-  static async getPool(): Promise<Pool> {
-    if (DB.pool === null) {
-      DB.pool = createPool(DB.poolConfig());
-      DB.pool.on('connection', function (newConnection: PoolConnection) {
+  public async checkDbConnection() {
+    try {
+      await this.query('SELECT ?', [1]);
+      logger.info('Database connection established.');
+    } catch (e) {
+      logger.err('Could not connect to database: ' + (e instanceof Error ? e.message : e));
+      process.exit(1);
+    }
+  }
+
+  private async getPool(): Promise<Pool> {
+    if (this.pool === null) {
+      this.pool = createPool(this.poolConfig);
+      this.pool.on('connection', function (newConnection: PoolConnection) {
         newConnection.query(`SET time_zone='+00:00'`);
       });
     }
-    return DB.pool;
-  }
-
-  static async query(query, params?) {
-    const pool = await DB.getPool();
-    return pool.query(query, params);
+    return this.pool;
   }
 }
 
-export async function checkDbConnection() {
-  try {
-    await DB.query('SELECT ?', [1]);
-    logger.info('Database connection established.');
-  } catch (e) {
-    logger.err('Could not connect to database: ' + (e instanceof Error ? e.message : e));
-    process.exit(1);
-  }
-}
+export default new DB();
diff --git a/backend/src/index.ts b/backend/src/index.ts
index 1081c5468..c2f111c65 100644
--- a/backend/src/index.ts
+++ b/backend/src/index.ts
@@ -5,7 +5,7 @@ import * as WebSocket from 'ws';
 import * as cluster from 'cluster';
 import axios from 'axios';
 
-import { checkDbConnection, DB } from './database';
+import DB from './database';
 import config from './config';
 import routes from './routes';
 import blocks from './api/blocks';
@@ -89,7 +89,7 @@ class Server {
     diskCache.loadMempoolCache();
 
     if (config.DATABASE.ENABLED) {
-      await checkDbConnection();
+      await DB.checkDbConnection();
       try {
         if (process.env.npm_config_reindex != undefined) { // Re-index requests
           const tables = process.env.npm_config_reindex.split(',');
diff --git a/backend/src/repositories/BlocksRepository.ts b/backend/src/repositories/BlocksRepository.ts
index e35647fd2..8e96a0c38 100644
--- a/backend/src/repositories/BlocksRepository.ts
+++ b/backend/src/repositories/BlocksRepository.ts
@@ -1,5 +1,5 @@
-import { BlockExtended, PoolTag } from '../mempool.interfaces';
-import { DB } from '../database';
+import { BlockExtended } from '../mempool.interfaces';
+import DB from '../database';
 import logger from '../logger';
 import { Common } from '../api/common';
 import { prepareBlock } from '../utils/blocks-utils';
diff --git a/backend/src/repositories/HashratesRepository.ts b/backend/src/repositories/HashratesRepository.ts
index 1701d2236..8388b9122 100644
--- a/backend/src/repositories/HashratesRepository.ts
+++ b/backend/src/repositories/HashratesRepository.ts
@@ -1,5 +1,5 @@
 import { Common } from '../api/common';
-import { DB } from '../database';
+import DB from '../database';
 import logger from '../logger';
 import PoolsRepository from './PoolsRepository';
 
diff --git a/backend/src/repositories/PoolsRepository.ts b/backend/src/repositories/PoolsRepository.ts
index c1f8cc80f..037a6250a 100644
--- a/backend/src/repositories/PoolsRepository.ts
+++ b/backend/src/repositories/PoolsRepository.ts
@@ -1,6 +1,6 @@
 import { Common } from '../api/common';
 import config from '../config';
-import { DB } from '../database';
+import DB from '../database';
 import logger from '../logger';
 import { PoolInfo, PoolTag } from '../mempool.interfaces';
 
diff --git a/backend/src/tasks/pools-updater.ts b/backend/src/tasks/pools-updater.ts
index 90937a16f..aee786ff9 100644
--- a/backend/src/tasks/pools-updater.ts
+++ b/backend/src/tasks/pools-updater.ts
@@ -1,7 +1,7 @@
 const https = require('https');
 import poolsParser from '../api/pools-parser';
 import config from '../config';
-import { DB } from '../database';
+import DB from '../database';
 import logger from '../logger';
 
 /**