Exploration to reduce deadlocks

apps/platform/db/migrations/20241228214210_modify_journey_user_step_indexes.js

@@ -0,0 +1,13 @@
+exports.up = async function(knex) {
+    await knex.schema.alterTable('journey_user_step', function(table) {
+        table.index(['journey_id', 'type', 'delay_until'])
+        table.dropIndex(['type', 'delay_until'])
+    })
+}
+
+exports.down = async function(knex) {
+    await knex.schema.alterTable('journey_user_step', function(table) {
+        table.index(['type', 'delay_until'])
+        table.dropIndex(['journey_id', 'type', 'delay_until'])
+    })
+}

apps/platform/src/lists/ListEvaluateUserJob.ts

@@ -1,7 +1,6 @@
 import App from '../app'
 import { cacheIncr } from '../config/redis'
 import { Job } from '../queue'
-import { JobPriority } from '../queue/Job'
 import { getUser } from '../users/UserRepository'
 import { DynamicList } from './List'
 import { CacheKeys, cleanupList, evaluateUserList, getList } from './ListService'
@@ -17,12 +16,6 @@ interface ListEvaluateUserParams {
 export default class ListEvaluateUserJob extends Job {
     static $name = 'list_evaluate_user_job'
 
-    options = {
-        delay: 0,
-        attempts: 3,
-        priority: JobPriority.low,
-    }
-
     static from(params: ListEvaluateUserParams): ListEvaluateUserJob {
         return new this(params)
     }

apps/platform/src/utilities/index.ts

@@ -224,9 +224,22 @@ export const chunk = async <T>(
     modifier: (result: any) => T = (result) => result,
 ) => {
     const chunker = new Chunker(callback, size)
+    const handler = async (result: any, retries = 3) => {
+        try {
+            await chunker.add(modifier(result))
+        } catch (error: any) {
+
+            // In the case of deadlocks, retry the operation
+            if (['ER_LOCK_WAIT_TIMEOUT', 'ER_LOCK_DEADLOCK'].includes(error.code) && retries > 0) {
+                setTimeout(() => handler(result, retries - 1), 250)
+            } else {
+                throw error
+            }
+        }
+    }
     await query.stream(async function(stream) {
         for await (const result of stream) {
-            await chunker.add(modifier(result))
+            await handler(result)
         }
     })
     await chunker.flush()