From 2af32ac4b03a4c709ba27629ca2272f7d09a783c Mon Sep 17 00:00:00 2001
From: Stephan Kulla <git.mail@kulla.me>
Date: Tue, 28 May 2024 10:47:53 +0200
Subject: [PATCH] wip: Replay transactions on deadlock

---
 packages/server/src/database.ts            | 32 ++++++++++++++++++++++
 packages/server/src/schema/events/event.ts | 10 ++-----
 2 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/packages/server/src/database.ts b/packages/server/src/database.ts
index 9b6607858..3d20d6306 100644
--- a/packages/server/src/database.ts
+++ b/packages/server/src/database.ts
@@ -16,6 +16,38 @@ export class Database {
     this.state = { type: 'OutsideOfTransaction' }
   }
 
+  public async withTransaction(fn: () => Promise<void>) {
+    const transaction = await this.beginTransaction()
+
+    try {
+      await fn()
+
+      await transaction.commit()
+    } catch (error: unknown) {
+      console.log(error)
+
+      if (this.state.type !== 'OutsideOfTransaction') {
+        console.log(
+          await this.state.transaction.query('SHOW ENGINE INNODB STATUS;'),
+        )
+      }
+
+      await transaction.rollback()
+
+      if (
+        error instanceof Error &&
+        'code' in error &&
+        error.code === 'ER_LOCK_DEADLOCK'
+      ) {
+        console.log('deadlock detected, retrying')
+
+        await this.withTransaction(fn)
+      } else {
+        throw error
+      }
+    }
+  }
+
   public async beginTransaction() {
     if (this.state.type === 'OutsideOfTransaction') {
       const transaction = await this.pool.getConnection()
diff --git a/packages/server/src/schema/events/event.ts b/packages/server/src/schema/events/event.ts
index b98a62a6b..3da2968a6 100644
--- a/packages/server/src/schema/events/event.ts
+++ b/packages/server/src/schema/events/event.ts
@@ -34,9 +34,7 @@ export async function createEvent(
   const abstractEventPayload = toDatabaseRepresentation(payload)
   const { type, actorId, objectId, instance } = abstractEventPayload
 
-  const transaction = await database.beginTransaction()
-
-  try {
+  await database.withTransaction(async () => {
     const { insertId: eventId } = await database.mutate(
       `
       INSERT INTO event_log (actor_id, event_id, uuid_id, instance_id)
@@ -83,11 +81,7 @@ export async function createEvent(
     const event = { ...abstractEventPayload, id: eventId }
 
     await createNotifications(event, { database })
-
-    await transaction.commit()
-  } finally {
-    await transaction.rollback()
-  }
+  })
 }
 
 async function createNotifications(