Merge pull request #2392 from matrix-org/matthew/fix-sync-acc-overlap

Prevent overlapping sync accumulator persists
matrix-org · May 21, 2022 · 25afb7c · 25afb7c
2 parents a9516d0 + c12932b
commit 25afb7c
Showing 1 changed file with 23 additions and 6 deletions.
diff --git a/src/store/indexeddb-local-backend.ts b/src/store/indexeddb-local-backend.ts
@@ -127,6 +127,8 @@ export class LocalIndexedDBStoreBackend implements IIndexedDBBackend {
     private db: IDBDatabase = null;
     private disconnected = true;
     private _isNewlyCreated = false;
+    private isPersisting = false;
+    private pendingUserPresenceData: UserTuple[] = [];
 
     /**
      * Does the actual reading from and writing to the indexeddb
@@ -401,11 +403,24 @@ export class LocalIndexedDBStoreBackend implements IIndexedDBBackend {
     public async syncToDatabase(userTuples: UserTuple[]): Promise<void> {
         const syncData = this.syncAccumulator.getJSON(true);
 
-        await Promise.all([
-            this.persistUserPresenceEvents(userTuples),
-            this.persistAccountData(syncData.accountData),
-            this.persistSyncData(syncData.nextBatch, syncData.roomsData),
-        ]);
+        if (this.isPersisting) {
+            logger.warn("Skipping syncToDatabase() as persist already in flight");
+            this.pendingUserPresenceData.push(...userTuples);
+            return;
+        } else {
+            userTuples.unshift(...this.pendingUserPresenceData);
+            this.isPersisting = true;
+        }
+
+        try {
+            await Promise.all([
+                this.persistUserPresenceEvents(userTuples),
+                this.persistAccountData(syncData.accountData),
+                this.persistSyncData(syncData.nextBatch, syncData.roomsData),
+            ]);
+        } finally {
+            this.isPersisting = false;
+        }
     }
 
     /**
@@ -427,7 +442,9 @@ export class LocalIndexedDBStoreBackend implements IIndexedDBBackend {
                 nextBatch,
                 roomsData,
             }); // put == UPSERT
-            return txnAsPromise(txn).then();
+            return txnAsPromise(txn).then(() => {
+                logger.log("Persisted sync data up to", nextBatch);
+            });
         });
     }