fix(indexer): use db lock mode to prevent multiple records in last pr…

…ocessed event table
dzhelezov · Jun 14, 2020 · 91fe1dd · 91fe1dd
1 parent 8524ac4
commit 91fe1dd
Showing 1 changed file with 30 additions and 9 deletions.
diff --git a/substrate-query-framework/index-builder/src/db/entities.ts b/substrate-query-framework/index-builder/src/db/entities.ts
@@ -35,16 +35,37 @@ export class SavedEntityEvent {
    * @param event
    */
   static async update(event: SubstrateEvent, manager: EntityManager): Promise<void> {
-    let lastProcessedEvent = await manager.findOne(SavedEntityEvent);
+    let lastProcessedEvent = await manager
+      .getRepository(SavedEntityEvent)
+      .createQueryBuilder('saved_entity_event')
+      .select()
+      .limit(1)
+      .setLock('pessimistic_read')
+      .getOne();
 
-    if (!lastProcessedEvent) {
-      lastProcessedEvent = new SavedEntityEvent();
-    }
-
-    lastProcessedEvent.index = event.index;
-    lastProcessedEvent.eventName = event.event_method;
-    lastProcessedEvent.blockNumber = event.block_number;
+    if (lastProcessedEvent) {
+      await manager
+        .getRepository(SavedEntityEvent)
+        .createQueryBuilder()
+        .setLock('pessimistic_write')
+        .update()
+        .set({ index: event.index, eventName: event.event_method, blockNumber: event.block_number })
+        .execute();
+    } else {
+      lastProcessedEvent = new SavedEntityEvent({
+        index: event.index,
+        eventName: event.event_method,
+        blockNumber: event.block_number,
+      });
 
-    await manager.save(lastProcessedEvent);
+      await manager
+        .getRepository(SavedEntityEvent)
+        .createQueryBuilder()
+        .setLock('pessimistic_write')
+        .insert()
+        .into(SavedEntityEvent)
+        .values(lastProcessedEvent)
+        .execute();
+    }
   }
 }