Estimate accelerated positions in partner mempools

backend/src/api/mempool-blocks.ts

@@ -1,12 +1,13 @@
 import { GbtGenerator, GbtResult, ThreadTransaction as RustThreadTransaction, ThreadAcceleration as RustThreadAcceleration } from 'rust-gbt';
 import logger from '../logger';
-import { MempoolBlock, MempoolTransactionExtended, MempoolBlockWithTransactions, MempoolBlockDelta, Ancestor, CompactThreadTransaction, EffectiveFeeStats, TransactionClassified, TransactionCompressed, MempoolDeltaChange, GbtCandidates } from '../mempool.interfaces';
+import { MempoolBlock, MempoolTransactionExtended, MempoolBlockWithTransactions, MempoolBlockDelta, Ancestor, CompactThreadTransaction, EffectiveFeeStats, TransactionClassified, TransactionCompressed, MempoolDeltaChange, GbtCandidates, PoolTag } from '../mempool.interfaces';
 import { Common, OnlineFeeStatsCalculator } from './common';
 import config from '../config';
 import { Worker } from 'worker_threads';
 import path from 'path';
 import mempool from './mempool';
 import { Acceleration } from './services/acceleration';
+import PoolsRepository from '../repositories/PoolsRepository';
 
 const MAX_UINT32 = Math.pow(2, 32) - 1;
 
@@ -21,6 +22,17 @@ class MempoolBlocks {
   private uidMap: Map<number, string> = new Map(); // map short numerical uids to full txids
   private txidMap: Map<string, number> = new Map(); // map full txids back to short numerical uids
 
+  private pools: { [id: number]: PoolTag } = {};
+
+  constructor() {
+    PoolsRepository.$getPools().then(allPools => {
+      this.pools = {};
+      for (const pool of allPools) {
+        this.pools[pool.uniqueId] = pool;
+      }
+    });
+  }
+
   public getMempoolBlocks(): MempoolBlock[] {
     return this.mempoolBlocks.map((block) => {
       return {
@@ -478,7 +490,7 @@ class MempoolBlocks {
       const deltas = this.calculateMempoolDeltas(this.mempoolBlocks, mempoolBlocks);
       this.mempoolBlocks = mempoolBlocks;
       this.mempoolBlockDeltas = deltas;
-
+      this.updateAccelerationPositions(mempool, accelerations, mempoolBlocks);
     }
 
     return mempoolBlocks;
@@ -625,6 +637,124 @@ class MempoolBlocks {
       tx.acc ? 1 : 0,
     ];
   }
+
+  // estimates and saves positions of accelerations in mining partner mempools
+  private updateAccelerationPositions(mempoolCache: { [txid: string]: MempoolTransactionExtended }, accelerations: { [txid: string]: Acceleration }, mempoolBlocks: MempoolBlockWithTransactions[]): void {
+    const accelerationPositions: { [txid: string]: { poolId: number, pool: string, block: number, vsize: number }[] } = {};
+    // keep track of simulated mempool blocks for each active pool
+    const pools: {
+      [pool: string]: { name: string, block: number, vsize: number, accelerations: string[], complete: boolean };
+    } = {};
+    // prepare a list of accelerations in ascending order (we'll pop items off the end of the list)
+    const accQueue: { acceleration: Acceleration, rate: number, vsize: number }[] = Object.values(accelerations).map(acc => {
+      let vsize = mempoolCache[acc.txid].vsize;
+      for (const ancestor of mempoolCache[acc.txid].ancestors || []) {
+        vsize += (ancestor.weight / 4);
+      }
+      return {
+        acceleration: acc,
+        rate: mempoolCache[acc.txid].effectiveFeePerVsize,
+        vsize
+      };
+    }).sort((a, b) => a.rate - b.rate);
+    // initialize the pool tracker
+    for (const { acceleration }  of accQueue) {
+      accelerationPositions[acceleration.txid] = [];
+      for (const pool of acceleration.pools) {
+        if (!pools[pool]) {
+          pools[pool] = {
+            name: this.pools[pool]?.name || 'unknown',
+            block: 0,
+            vsize: 0,
+            accelerations: [],
+            complete: false,
+          };
+        }
+        pools[pool].accelerations.push(acceleration.txid);
+      }
+      for (const ancestor of mempoolCache[acceleration.txid].ancestors || []) {
+        accelerationPositions[ancestor.txid] = [];
+      }
+    }
+
+    for (const pool of Object.keys(pools)) {
+      // if any pools accepted *every* acceleration, we can just use the GBT result positions directly
+      if (pools[pool].accelerations.length === Object.keys(accelerations).length) {
+        pools[pool].complete = true;
+      }
+    }
+
+    let block = 0;
+    let index = 0;
+    let next = accQueue.pop();
+    // build simulated blocks for each pool by taking the best option from
+    // either the mempool or the list of accelerations.
+    while (next && block < mempoolBlocks.length) {
+      while (next && index < mempoolBlocks[block].transactions.length) {
+        const nextTx = mempoolBlocks[block].transactions[index];
+        if (next.rate >= (nextTx.rate || (nextTx.fee / nextTx.vsize))) {
+          for (const pool of next.acceleration.pools) {
+            if (pools[pool].vsize + next.vsize <= 999_000) {
+              pools[pool].vsize += next.vsize;
+            } else {
+              pools[pool].block++;
+              pools[pool].vsize = next.vsize;
+            }
+            // insert the acceleration into matching pool's blocks
+            if (pools[pool].complete && mempoolCache[next.acceleration.txid]?.position !== undefined) {
+              accelerationPositions[next.acceleration.txid].push({
+                ...mempoolCache[next.acceleration.txid].position as { block: number, vsize: number },
+                poolId: pool,
+                pool: pools[pool].name
+              });
+            } else {
+              accelerationPositions[next.acceleration.txid].push({
+                poolId: pool,
+                pool: pools[pool].name,
+                block: pools[pool].block,
+                vsize: pools[pool].vsize - (next.vsize / 2),
+              });
+            }
+            // and any accelerated ancestors
+            for (const ancestor of mempoolCache[next.acceleration.txid].ancestors || []) {
+              if (pools[pool].complete && mempoolCache[ancestor.txid]?.position !== undefined) {
+                accelerationPositions[ancestor.txid].push({
+                  ...mempoolCache[ancestor.txid].position as { block: number, vsize: number },
+                  poolId: pool,
+                  pool: pools[pool].name,
+                });
+              } else {
+                accelerationPositions[ancestor.txid].push({
+                  poolId: pool,
+                  pool: pools[pool].name,
+                  block: pools[pool].block,
+                  vsize: pools[pool].vsize - (next.vsize / 2),
+                });
+              }
+            }
+          }
+          next = accQueue.pop();
+        } else {
+          // skip accelerated transactions and their CPFP ancestors
+          if (accelerationPositions[nextTx.txid] == null) {
+            // insert into all pools' blocks
+            for (const pool of Object.keys(pools)) {
+              if (pools[pool].vsize + nextTx.vsize <= 999_000) {
+                pools[pool].vsize += nextTx.vsize;
+              } else {
+                pools[pool].block++;
+                pools[pool].vsize = nextTx.vsize;
+              }
+            }
+          }
+          index++;
+        }
+      }
+      block++;
+      index = 0;
+    }
+    mempool.setAccelerationPositions(accelerationPositions);
+  }
 }
 
 export default new MempoolBlocks();

backend/src/api/mempool.ts

@@ -27,6 +27,7 @@ class Mempool {
     deletedTransactions: MempoolTransactionExtended[], accelerationDelta: string[], candidates?: GbtCandidates) => Promise<void>) | undefined;
 
   private accelerations: { [txId: string]: Acceleration } = {};
+  private accelerationPositions: { [txid: string]: { poolId: number, pool: string, block: number, vsize: number }[] } = {};
 
   private txPerSecondArray: number[] = [];
   private txPerSecond: number = 0;
@@ -514,6 +515,14 @@ class Mempool {
     }
   }
 
+  setAccelerationPositions(positions: { [txid: string]: { poolId: number, pool: string, block: number, vsize: number }[] }): void {
+    this.accelerationPositions = positions;
+  }
+
+  getAccelerationPositions(txid: string): { [pool: number]: { poolId: number, pool: string, block: number, vsize: number } } | undefined {
+    return this.accelerationPositions[txid];
+  }
+
   private startTimer() {
     const state: any = {
       start: Date.now(),

backend/src/api/services/acceleration.ts

@@ -10,6 +10,12 @@ export interface Acceleration {
   effectiveFee: number,
   feeDelta: number,
   pools: number[],
+  positions?: {
+    [pool: number]: {
+      block: number,
+      vbytes: number,
+    },
+  },
 };
 
 export interface AccelerationHistory {

backend/src/api/websocket-handler.ts

@@ -206,7 +206,8 @@ class WebsocketHandler {
                 }
                 response['txPosition'] = JSON.stringify({
                   txid: trackTxid,
-                  position
+                  position,
+                  accelerationPositions: memPool.getAccelerationPositions(tx.txid),
                 });
               }
             } else {
@@ -821,7 +822,8 @@ class WebsocketHandler {
               ...mempoolTx.position,
               accelerated: mempoolTx.acceleration || undefined,
               acceleratedBy: mempoolTx.acceleratedBy || undefined,
-            }
+            },
+            accelerationPositions: memPool.getAccelerationPositions(mempoolTx.txid),
           };
           if (!mempoolTx.cpfpChecked && !mempoolTx.acceleration) {
             calculateCpfp(mempoolTx, newMempool);
@@ -834,7 +836,7 @@ class WebsocketHandler {
               effectiveFeePerVsize: mempoolTx.effectiveFeePerVsize || null,
               sigops: mempoolTx.sigops,
               adjustedVsize: mempoolTx.adjustedVsize,
-              acceleration: mempoolTx.acceleration
+              acceleration: mempoolTx.acceleration,
             };
           }
           response['txPosition'] = JSON.stringify(positionData);
@@ -1137,7 +1139,8 @@ class WebsocketHandler {
                 ...mempoolTx.position,
                 accelerated: mempoolTx.acceleration || undefined,
                 acceleratedBy: mempoolTx.acceleratedBy || undefined,
-              }
+              },
+              accelerationPositions: memPool.getAccelerationPositions(mempoolTx.txid),
             });
           }
         }