Merge pull request #4045 from mempool/mononaut/fast-blocks

Faster blocks

backend/src/api/bitcoin/bitcoin-api-abstract-factory.ts

@@ -8,6 +8,7 @@ export interface AbstractBitcoinApi {
   $getBlockHeightTip(): Promise<number>;
   $getBlockHashTip(): Promise<string>;
   $getTxIdsForBlock(hash: string): Promise<string[]>;
+  $getTxsForBlock(hash: string): Promise<IEsploraApi.Transaction[]>;
   $getBlockHash(height: number): Promise<string>;
   $getBlockHeader(hash: string): Promise<string>;
   $getBlock(hash: string): Promise<IEsploraApi.Block>;

backend/src/api/bitcoin/bitcoin-api.ts

@@ -81,6 +81,10 @@ class BitcoinApi implements AbstractBitcoinApi {
       .then((rpcBlock: IBitcoinApi.Block) => rpcBlock.tx);
   }
 
+  $getTxsForBlock(hash: string): Promise<IEsploraApi.Transaction[]> {
+    throw new Error('Method getTxsForBlock not supported by the Bitcoin RPC API.');
+  }
+
   $getRawBlock(hash: string): Promise<Buffer> {
     return this.bitcoindClient.getBlock(hash, 0)
       .then((raw: string) => Buffer.from(raw, "hex"));

backend/src/api/bitcoin/esplora-api.ts

@@ -89,6 +89,10 @@ class ElectrsApi implements AbstractBitcoinApi {
     return this.$queryWrapper<string[]>(config.ESPLORA.REST_API_URL + '/block/' + hash + '/txids');
   }
 
+  $getTxsForBlock(hash: string): Promise<IEsploraApi.Transaction[]> {
+    return this.$queryWrapper<IEsploraApi.Transaction[]>(config.ESPLORA.REST_API_URL + '/block/' + hash + '/txs');
+  }
+
   $getBlockHash(height: number): Promise<string> {
     return this.$queryWrapper<string>(config.ESPLORA.REST_API_URL + '/block-height/' + height);
   }

backend/src/api/blocks.ts

@@ -70,6 +70,9 @@ class Blocks {
    * @param blockHash
    * @param blockHeight
    * @param onlyCoinbase - Set to true if you only need the coinbase transaction
+   * @param txIds - optional ordered list of transaction ids if already known
+   * @param quiet - don't print non-essential logs
+   * @param addMempoolData - calculate sigops etc
    * @returns Promise<TransactionExtended[]>
    */
   private async $getTransactionsExtended(
@@ -80,62 +83,77 @@ class Blocks {
     quiet: boolean = false,
     addMempoolData: boolean = false,
   ): Promise<TransactionExtended[]> {
-    const transactions: TransactionExtended[] = [];
+    const isEsplora = config.MEMPOOL.BACKEND === 'esplora';
+    const transactionMap: { [txid: string]: TransactionExtended } = {};
+
     if (!txIds) {
       txIds = await bitcoinApi.$getTxIdsForBlock(blockHash);
     }
 
     const mempool = memPool.getMempool();
-    let transactionsFound = 0;
+    let foundInMempool = 0;
-    let transactionsFetched = 0;
+    let totalFound = 0;
 
-    for (let i = 0; i < txIds.length; i++) {
+    // Copy existing transactions from the mempool
-      if (mempool[txIds[i]]) {
+    if (!onlyCoinbase) {
-        // We update blocks before the mempool (index.ts), therefore we can
+      for (const txid of txIds) {
-        // optimize here by directly fetching txs in the "outdated" mempool
+        if (mempool[txid]) {
-        transactions.push(mempool[txIds[i]]);
+          transactionMap[txid] = mempool[txid];
-        transactionsFound++;
+          foundInMempool++;
-      } else if (config.MEMPOOL.BACKEND === 'esplora' || !memPool.hasPriority() || i === 0) {
+          totalFound++;
-        // Otherwise we fetch the tx data through backend services (esplora, electrum, core rpc...)
-        if (!quiet && (i % (Math.round((txIds.length) / 10)) === 0 || i + 1 === txIds.length)) { // Avoid log spam
-          logger.debug(`Indexing tx ${i + 1} of ${txIds.length} in block #${blockHeight}`);
-        }
-        try {
-          const tx = await transactionUtils.$getTransactionExtended(txIds[i], false, false, false, addMempoolData);
-          transactions.push(tx);
-          transactionsFetched++;
-        } catch (e) {
-          try {
-            if (config.MEMPOOL.BACKEND === 'esplora') {
-              // Try again with core
-              const tx = await transactionUtils.$getTransactionExtended(txIds[i], false, false, true, addMempoolData);
-              transactions.push(tx);
-              transactionsFetched++;
-            } else {
-              throw e;
-            }
-          } catch (e) {
-            if (i === 0) {
-              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));
-            }
-          }
         }
       }
+    }
 
-      if (onlyCoinbase === true) {
+    // Skip expensive lookups while mempool has priority
-        break; // Fetch the first transaction and exit
+    if (onlyCoinbase) {
+      try {
+        const coinbase = await transactionUtils.$getTransactionExtended(txIds[0], false, false, false, addMempoolData);
+        return [coinbase];
+      } catch (e) {
+        const msg = `Cannot fetch coinbase tx ${txIds[0]}. Reason: ` + (e instanceof Error ? e.message : e);
+        logger.err(msg);
+        throw new Error(msg);
+      }
+    }
+
+    // Fetch remaining txs in bulk
+    if (isEsplora && (txIds.length - totalFound > 500)) {
+      try {
+        const rawTransactions = await bitcoinApi.$getTxsForBlock(blockHash);
+        for (const tx of rawTransactions) {
+          if (!transactionMap[tx.txid]) {
+            transactionMap[tx.txid] = addMempoolData ? transactionUtils.extendMempoolTransaction(tx) : transactionUtils.extendTransaction(tx);
+            totalFound++;
+          }
+        }
+      } catch (e) {
+        logger.err(`Cannot fetch bulk txs for block ${blockHash}. Reason: ` + (e instanceof Error ? e.message : e));
+      }
+    }
+
+    // Fetch remaining txs individually
+    for (const txid of txIds.filter(txid => !transactionMap[txid])) {
+      if (!transactionMap[txid]) {
+        if (!quiet && (totalFound % (Math.round((txIds.length) / 10)) === 0 || totalFound + 1 === txIds.length)) { // Avoid log spam
+          logger.debug(`Indexing tx ${totalFound + 1} of ${txIds.length} in block #${blockHeight}`);
+        }
+        try {
+          const tx = await transactionUtils.$getTransactionExtended(txid, false, false, false, addMempoolData);
+          transactionMap[txid] = tx;
+          totalFound++;
+        } catch (e) {
+          logger.err(`Cannot fetch tx ${txid}. Reason: ` + (e instanceof Error ? e.message : e));
+        }
       }
     }
 
     if (!quiet) {
-      logger.debug(`${transactionsFound} of ${txIds.length} found in mempool. ${transactionsFetched} fetched through backend service.`);
+      logger.debug(`${foundInMempool} of ${txIds.length} found in mempool. ${totalFound - foundInMempool} fetched through backend service.`);
     }
 
-    return transactions;
+    // Return list of transactions, preserving block order
+    return txIds.map(txid => transactionMap[txid]).filter(tx => tx != null);
   }
 
   /**

backend/src/api/transaction-utils.ts

@@ -53,7 +53,7 @@ class TransactionUtils {
     return (await this.$getTransactionExtended(txId, addPrevouts, lazyPrevouts, forceCore, true)) as MempoolTransactionExtended;
   }
 
-  private extendTransaction(transaction: IEsploraApi.Transaction): TransactionExtended {
+  public extendTransaction(transaction: IEsploraApi.Transaction): TransactionExtended {
     // @ts-ignore
     if (transaction.vsize) {
       // @ts-ignore