Merge pull request #1554 from mempool/nymkappa/bugfix/fast-forward-re-org

Validate block hash chain after indexing and for new blocks

backend/src/api/blocks.ts

@@ -13,6 +13,8 @@ import blocksRepository from '../repositories/BlocksRepository';
 import loadingIndicators from './loading-indicators';
 import BitcoinApi from './bitcoin/bitcoin-api';
 import { prepareBlock } from '../utils/blocks-utils';
+import BlocksRepository from '../repositories/BlocksRepository';
+import HashratesRepository from '../repositories/HashratesRepository';
 
 class Blocks {
   private blocks: BlockExtended[] = [];
@@ -23,7 +25,7 @@ class Blocks {
   private newBlockCallbacks: ((block: BlockExtended, txIds: string[], transactions: TransactionExtended[]) => void)[] = [];
   private blockIndexingStarted = false;
   public blockIndexingCompleted = false;
-  public reindexFlag = true; // Always re-index the latest indexed data in case the node went offline with an invalid block tip (reorg)
+  public reindexFlag = false;
 
   constructor() { }
 
@@ -272,10 +274,13 @@ class Blocks {
       return;
     }
 
-    this.blockIndexingCompleted = true;
+    const chainValid = await BlocksRepository.$validateChain();
+    this.reindexFlag = !chainValid;
+    this.blockIndexingCompleted = chainValid;
   }
 
   public async $updateBlocks() {
+    let fastForwarded = false;
     const blockHeightTip = await bitcoinApi.$getBlockHeightTip();
 
     if (this.blocks.length === 0) {
@@ -287,6 +292,7 @@ class Blocks {
     if (blockHeightTip - this.currentBlockHeight > config.MEMPOOL.INITIAL_BLOCKS_AMOUNT * 2) {
       logger.info(`${blockHeightTip - this.currentBlockHeight} blocks since tip. Fast forwarding to the ${config.MEMPOOL.INITIAL_BLOCKS_AMOUNT} recent blocks`);
       this.currentBlockHeight = blockHeightTip - config.MEMPOOL.INITIAL_BLOCKS_AMOUNT;
+      fastForwarded = true;
     }
 
     if (!this.lastDifficultyAdjustmentTime) {
@@ -324,12 +330,18 @@ class Blocks {
       const blockExtended: BlockExtended = await this.$getBlockExtended(block, transactions);
 
       if (Common.indexingEnabled()) {
-        await blocksRepository.$saveBlockInDatabase(blockExtended);
+        if (!fastForwarded) {
-
+          const lastBlock = await blocksRepository.$getBlockByHeight(blockExtended.height - 1);
-        // If the last 10 blocks chain is not valid, re-index them (reorg)
+          if (lastBlock !== null && blockExtended.previousblockhash !== lastBlock['hash']) {
-        const chainValid = await blocksRepository.$validateRecentBlocks();
+            logger.warn(`Chain divergence detected at block ${lastBlock['height']}, re-indexing most recent data`);
-        if (!chainValid) {
+            // We assume there won't be a reorg with more than 10 block depth
-          this.reindexFlag = true;
+            await BlocksRepository.$deleteBlocksFrom(lastBlock['height'] - 10);
+            await HashratesRepository.$deleteLastEntries();
+            for (let i = 10; i >= 0; --i) {
+              await this.$indexBlock(lastBlock['height'] - i);
+            }
+          }
+          await blocksRepository.$saveBlockInDatabase(blockExtended);
         }
       }
 

backend/src/index.ts

@@ -188,10 +188,6 @@ class Server {
 
     try {
       await poolsUpdater.updatePoolsJson();
-      if (blocks.reindexFlag) {
-        await BlocksRepository.$deleteBlocks(10);
-        await HashratesRepository.$deleteLastEntries();
-      }
       await blocks.$generateBlockDatabase();
       await mining.$generateNetworkHashrateHistory();
       await mining.$generatePoolHashrateHistory();

backend/src/repositories/BlocksRepository.ts

@@ -4,6 +4,7 @@ import logger from '../logger';
 import { Common } from '../api/common';
 import { prepareBlock } from '../utils/blocks-utils';
 import PoolsRepository from './PoolsRepository';
+import HashratesRepository from './HashratesRepository';
 
 class BlocksRepository {
   /**
@@ -370,15 +371,43 @@ class BlocksRepository {
   }
 
   /**
-   * Delete $count blocks from the database
+   * Check if the chain of block hash is valid and delete data from the stale branch if needed
    */
-  public async $deleteBlocks(count: number) {
+  public async $validateChain(): Promise<boolean> {
-    logger.info(`Delete ${count} most recent indexed blocks from the database`);
+    try {
+      const start = new Date().getTime();
+      const [blocks]: any[] = await DB.query(`SELECT height, hash, previous_block_hash,
+        UNIX_TIMESTAMP(blockTimestamp) as timestamp FROM blocks ORDER BY height`);
+
+      let currentHeight = 1;
+      while (currentHeight < blocks.length) {
+        if (blocks[currentHeight].previous_block_hash !== blocks[currentHeight - 1].hash) {
+          logger.warn(`Chain divergence detected at block ${blocks[currentHeight - 1].height}, re-indexing newer blocks and hashrates`);
+          await this.$deleteBlocksFrom(blocks[currentHeight - 1].height);
+          await HashratesRepository.$deleteHashratesFromTimestamp(blocks[currentHeight - 1].timestamp - 604800);
+          return false;
+        }
+        ++currentHeight;
+      }
+
+      logger.info(`${currentHeight} blocks hash validated in ${new Date().getTime() - start} ms`);
+      return true;
+    } catch (e) {
+      logger.err('Cannot validate chain of block hash. Reason: ' + (e instanceof Error ? e.message : e));
+      return true; // Don't do anything if there is a db error
+    }
+  }
+
+  /**
+   * Delete blocks from the database from blockHeight
+   */
+  public async $deleteBlocksFrom(blockHeight: number) {
+    logger.info(`Delete newer blocks from height ${blockHeight} from the database`);
 
     try {
-      await DB.query(`DELETE FROM blocks ORDER BY height DESC LIMIT ${count};`);
+      await DB.query(`DELETE FROM blocks where height >= ${blockHeight}`);
     } catch (e) {
-      logger.err('Cannot delete recent indexed blocks. Reason: ' + (e instanceof Error ? e.message : e));
+      logger.err('Cannot delete indexed blocks. Reason: ' + (e instanceof Error ? e.message : e));
     }
   }
 

backend/src/repositories/HashratesRepository.ts

@@ -195,6 +195,22 @@ class HashratesRepository {
       logger.err('Cannot delete latest hashrates data points. Reason: ' + (e instanceof Error ? e.message : e));
     }
   }
+  
+  /**
+   * Delete hashrates from the database from timestamp
+   */
+  public async $deleteHashratesFromTimestamp(timestamp: number) {
+    logger.info(`Delete newer hashrates from timestamp ${new Date(timestamp * 1000).toUTCString()} from the database`);
+
+    try {
+      await DB.query(`DELETE FROM hashrates WHERE hashrate_timestamp >= FROM_UNIXTIME(?)`, [timestamp]);
+      // Re-run the hashrate indexing to fill up missing data
+      await this.$setLatestRunTimestamp('last_hashrates_indexing', 0);
+      await this.$setLatestRunTimestamp('last_weekly_hashrates_indexing', 0);
+    } catch (e) {
+      logger.err('Cannot delete latest hashrates data points. Reason: ' + (e instanceof Error ? e.message : e));
+    }
+  }
 }
 
 export default new HashratesRepository();