From 320bf02938e313c08b30d0851c95b723015d5e8f Mon Sep 17 00:00:00 2001
From: prathamesh0 <42446521+prathamesh0@users.noreply.github.com>
Date: Wed, 25 Oct 2023 14:36:03 +0530
Subject: [PATCH] Fetch txs only for blocks having relevant events (#436)

* Fix address filter usage in rpc-eth-client getLogs implementation

* Avoid fetching block txs when no relevant logs exist
---
 .../src/templates/indexer-template.handlebars |  2 +-
 packages/rpc-eth-client/src/eth-client.ts     |  2 +-
 packages/util/src/indexer.ts                  | 48 +++++++++++--------
 3 files changed, 31 insertions(+), 21 deletions(-)

diff --git a/packages/codegen/src/templates/indexer-template.handlebars b/packages/codegen/src/templates/indexer-template.handlebars
index 6d5ee5da..e573651f 100644
--- a/packages/codegen/src/templates/indexer-template.handlebars
+++ b/packages/codegen/src/templates/indexer-template.handlebars
@@ -626,7 +626,7 @@ export class Indexer implements IndexerInterface {
   }
 
   async fetchEventsAndSaveBlocks (blocks: DeepPartial<BlockProgress>[]): Promise<{ blockProgress: BlockProgress, events: DeepPartial<Event>[] }[]> {
-    return this._baseIndexer.fetchEventsAndSaveBlocks(blocks, this.parseEventNameAndArgs.bind(this))
+    return this._baseIndexer.fetchEventsAndSaveBlocks(blocks, this.parseEventNameAndArgs.bind(this));
   }
 
   async saveBlockAndFetchEvents (block: DeepPartial<BlockProgress>): Promise<[BlockProgress, DeepPartial<Event>[]]> {
diff --git a/packages/rpc-eth-client/src/eth-client.ts b/packages/rpc-eth-client/src/eth-client.ts
index e68fada0..419585d7 100644
--- a/packages/rpc-eth-client/src/eth-client.ts
+++ b/packages/rpc-eth-client/src/eth-client.ts
@@ -279,7 +279,7 @@ export class EthClient implements EthClientInterface {
         let logs = logsByAddress.flat();
 
         // If no addresses provided to filter
-        if (!logs.length) {
+        if (!addresses.length) {
           logs = await this._provider.getLogs({
             fromBlock,
             toBlock
diff --git a/packages/util/src/indexer.ts b/packages/util/src/indexer.ts
index 8914fbed..f0dadb35 100644
--- a/packages/util/src/indexer.ts
+++ b/packages/util/src/indexer.ts
@@ -301,7 +301,7 @@ export class Indexer {
     }
 
     // Fetch logs for block range of given blocks
-    let logsPromise: Promise<any>;
+    let logs: any;
     const fromBlock = blocks[0].blockNumber;
     const toBlock = blocks[blocks.length - 1].blockNumber;
 
@@ -312,20 +312,43 @@ export class Indexer {
         return watchedContract.address;
       });
 
-      logsPromise = this._ethClient.getLogsForBlockRange({
+      ({ logs } = await this._ethClient.getLogsForBlockRange({
         fromBlock,
         toBlock,
         addresses
-      });
+      }));
     } else {
-      logsPromise = this._ethClient.getLogsForBlockRange({ fromBlock, toBlock });
+      ({ logs } = await this._ethClient.getLogsForBlockRange({ fromBlock, toBlock }));
     }
 
+    // Skip further processing if no relevant logs found in the entire block range
+    if (!logs.length) {
+      return new Map();
+    }
+
+    // Sort logs according to blockhash
+    const logsMap: Map<string, any> = new Map();
+    logs.forEach((log: any) => {
+      const { blockHash: logBlockHash } = log;
+      assert(typeof logBlockHash === 'string');
+
+      if (!logsMap.has(logBlockHash)) {
+        logsMap.set(logBlockHash, []);
+      }
+
+      logsMap.get(logBlockHash).push(log);
+    });
+
     // Fetch transactions for given blocks
     const transactionsMap: Map<string, any> = new Map();
     const transactionPromises = blocks.map(async (block) => {
       assert(block.blockHash);
 
+      // Skip fetching txs if no relevant logs found in this block
+      if (!logsMap.has(block.blockHash)) {
+        return;
+      }
+
       const blockWithTransactions = await this._ethClient.getBlockWithTransactions({ blockHash: block.blockHash, blockNumber: block.blockNumber });
       const {
         allEthHeaderCids: {
@@ -342,20 +365,7 @@ export class Indexer {
       transactionsMap.set(block.blockHash, transactions);
     });
 
-    const [{ logs }] = await Promise.all([logsPromise, ...transactionPromises]);
-
-    // Sort logs according to blockhash
-    const logsMap: Map<string, any> = new Map();
-    logs.forEach((log: any) => {
-      const { blockHash: logBlockHash } = log;
-      assert(typeof logBlockHash === 'string');
-
-      if (!logsMap.has(logBlockHash)) {
-        logsMap.set(logBlockHash, []);
-      }
-
-      logsMap.get(logBlockHash).push(log);
-    });
+    await Promise.all(transactionPromises);
 
     // Map db ready events according to blockhash
     const dbEventsMap: Map<string, DeepPartial<EventInterface>[]> = new Map();
@@ -364,7 +374,7 @@ export class Indexer {
       assert(blockHash);
 
       const logs = logsMap.get(blockHash) || [];
-      const transactions = transactionsMap.get(blockHash);
+      const transactions = transactionsMap.get(blockHash) || [];
 
       const dbEvents = this.createDbEventsFromLogsAndTxs(blockHash, logs, transactions, parseEventNameAndArgs);
       dbEventsMap.set(blockHash, dbEvents);