From 7dda953bc929e218121c331fedb3884b24555855 Mon Sep 17 00:00:00 2001
From: Alex Browne <stephenalexbrowne@gmail.com>
Date: Mon, 7 Jan 2019 15:04:00 -0800
Subject: [PATCH] Optimize SQL queries in pull_missing_blocks (#1458)

* Optimize SQL queries in pull_missing_blocks

* Update comment in pull_missing_blocks
---
 .../src/scripts/pull_missing_blocks.ts        | 39 ++++++++++---------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/packages/pipeline/src/scripts/pull_missing_blocks.ts b/packages/pipeline/src/scripts/pull_missing_blocks.ts
index bb53851266..ced9d99ebb 100644
--- a/packages/pipeline/src/scripts/pull_missing_blocks.ts
+++ b/packages/pipeline/src/scripts/pull_missing_blocks.ts
@@ -14,20 +14,29 @@ import { handleError, INFURA_ROOT_URL } from '../utils';
 // Number of blocks to save at once.
 const BATCH_SAVE_SIZE = 1000;
 // Maximum number of requests to send at once.
-const MAX_CONCURRENCY = 10;
+const MAX_CONCURRENCY = 20;
 // Maximum number of blocks to query for at once. This is also the maximum
 // number of blocks we will hold in memory prior to being saved to the database.
 const MAX_BLOCKS_PER_QUERY = 1000;
 
 let connection: Connection;
 
+const tablesWithMissingBlocks = [
+    'raw.exchange_fill_events',
+    'raw.exchange_cancel_events',
+    'raw.exchange_cancel_up_to_events',
+    'raw.erc20_approval_events',
+];
+
 (async () => {
     connection = await createConnection(ormConfig as ConnectionOptions);
     const provider = web3Factory.getRpcProvider({
         rpcUrl: INFURA_ROOT_URL,
     });
     const web3Source = new Web3Source(provider);
-    await getAllMissingBlocksAsync(web3Source);
+    for (const tableName of tablesWithMissingBlocks) {
+        await getAllMissingBlocksAsync(web3Source, tableName);
+    }
     process.exit(0);
 })().catch(handleError);
 
@@ -35,10 +44,11 @@ interface MissingBlocksResponse {
     block_number: string;
 }
 
-async function getAllMissingBlocksAsync(web3Source: Web3Source): Promise<void> {
+async function getAllMissingBlocksAsync(web3Source: Web3Source, tableName: string): Promise<void> {
     const blocksRepository = connection.getRepository(Block);
     while (true) {
-        const blockNumbers = await getMissingBlockNumbersAsync();
+        console.log(`Checking for missing blocks in ${tableName}...`);
+        const blockNumbers = await getMissingBlockNumbersAsync(tableName);
         if (blockNumbers.length === 0) {
             // There are no more missing blocks. We're done.
             break;
@@ -46,24 +56,14 @@ async function getAllMissingBlocksAsync(web3Source: Web3Source): Promise<void> {
         await getAndSaveBlocksAsync(web3Source, blocksRepository, blockNumbers);
     }
     const totalBlocks = await blocksRepository.count();
-    console.log(`Done saving blocks. There are now ${totalBlocks} total blocks.`);
+    console.log(`Done saving blocks for ${tableName}. There are now ${totalBlocks} total blocks.`);
 }
 
-async function getMissingBlockNumbersAsync(): Promise<number[]> {
-    // Note(albrow): The easiest way to get all the blocks we need is to
-    // consider all the events tables together in a single query. If this query
-    // gets too slow, we should consider re-architecting so that we can work on
-    // getting the blocks for one type of event at a time.
+async function getMissingBlockNumbersAsync(tableName: string): Promise<number[]> {
+    // This query returns up to `MAX_BLOCKS_PER_QUERY` distinct block numbers
+    // which are present in `tableName` but not in `raw.blocks`.
     const response = (await connection.query(
-        `WITH all_events AS (
-            SELECT block_number FROM raw.exchange_fill_events
-                UNION SELECT block_number FROM raw.exchange_cancel_events
-                UNION SELECT block_number FROM raw.exchange_cancel_up_to_events
-                UNION SELECT block_number FROM raw.erc20_approval_events
-        )
-        SELECT DISTINCT(block_number) FROM all_events
-            WHERE block_number NOT IN (SELECT number FROM raw.blocks)
-            ORDER BY block_number ASC LIMIT $1`,
+        `SELECT DISTINCT(block_number) FROM ${tableName} LEFT JOIN raw.blocks ON ${tableName}.block_number = raw.blocks.number WHERE number IS NULL LIMIT $1;`,
         [MAX_BLOCKS_PER_QUERY],
     )) as MissingBlocksResponse[];
     const blockNumberStrings = R.pluck('block_number', response);
@@ -86,4 +86,5 @@ async function getAndSaveBlocksAsync(
     const blocks = R.map(parseBlock, rawBlocks);
     console.log(`Saving ${blocks.length} blocks...`);
     await blocksRepository.save(blocks, { chunk: Math.ceil(blocks.length / BATCH_SAVE_SIZE) });
+    console.log('Done saving this batch of blocks');
 }