[Multi-Tab] Detect and recover from GCed Remote Document Changelog

packages/firestore/src/core/sync_engine.ts

@@ -42,7 +42,7 @@ import { SortedMap } from '../util/sorted_map';
 import { isNullOrUndefined } from '../util/types';
 
 import { isPrimaryLeaseLostError } from '../local/indexeddb_persistence';
-import { isRemoteDocumentChangesGarbageCollectedError } from '../local/indexeddb_remote_document_cache';
+import { isDocumentChangeMissingError } from '../local/indexeddb_remote_document_cache';
 import { ClientId, SharedClientState } from '../local/shared_client_state';
 import {
   QueryTargetState,
@@ -1016,7 +1016,7 @@ export class SyncEngine implements RemoteSyncer, SharedClientStateSyncer {
               );
             },
             async err => {
-              if (isRemoteDocumentChangesGarbageCollectedError(err)) {
+              if (isDocumentChangeMissingError(err)) {
                 const activeTargets: TargetId[] = [];
                 objUtils.forEachNumber(this.queryViewsByTarget, target =>
                   activeTargets.push(target)

packages/firestore/src/local/indexeddb_remote_document_cache.ts

@@ -41,7 +41,7 @@ import { PersistencePromise } from './persistence_promise';
 import { RemoteDocumentCache } from './remote_document_cache';
 import { SimpleDb, SimpleDbStore, SimpleDbTransaction } from './simple_db';
 
-const REMOTE_DOCUMENT_CHANGELOG_GARBAGE_COLLECTED_ERR_MSG =
+const REMOTE_DOCUMENT_CHANGE_MISSING_ERR_MSG =
   'The remote document changelog no longer contains all changes for all ' +
   'local query views. It may be necessary to rebuild these views.';
 
@@ -171,16 +171,22 @@ export class IndexedDbRemoteDocumentCache implements RemoteDocumentCache {
     );
     let firstIteration = true;
 
-    return documentChangesStore(transaction)
+    const changesStore = documentChangesStore(transaction);
+    return changesStore
       .iterate({ range }, (_, documentChange) => {
         if (firstIteration) {
           // If our client was throttled for more than 30 minutes, another
           // client may have garbage collected the remote document changelog.
           if (this._lastProcessedDocumentChangeId + 1 !== documentChange.id) {
-            return PersistencePromise.reject(
-              new FirestoreError(
-                Code.DATA_LOSS,
-                REMOTE_DOCUMENT_CHANGELOG_GARBAGE_COLLECTED_ERR_MSG
+            // Reset the `lastProcessedDocumentChangeId` to allow further
+            // invocations to successfully return the changes after this
+            // rejection.
+            return this.synchronizeLastDocumentChangeId(changesStore).next(() =>
+              PersistencePromise.reject(
+                new FirestoreError(
+                  Code.DATA_LOSS,
+                  REMOTE_DOCUMENT_CHANGE_MISSING_ERR_MSG
+                )
               )
             );
           }
@@ -221,13 +227,6 @@ export class IndexedDbRemoteDocumentCache implements RemoteDocumentCache {
     return documentChangesStore(transaction).delete(range);
   }
 
-  resetLastProcessedDocumentChange(
-    transaction: PersistenceTransaction
-  ): PersistencePromise<void> {
-    const store = documentChangesStore(transaction);
-    return this.synchronizeLastDocumentChangeId(store);
-  }
-
   private synchronizeLastDocumentChangeId(
     documentChangesStore: SimpleDbStore<
       DbRemoteDocumentChangesKey,
@@ -247,12 +246,10 @@ export class IndexedDbRemoteDocumentCache implements RemoteDocumentCache {
   }
 }
 
-export function isRemoteDocumentChangesGarbageCollectedError(
-  err: FirestoreError
-): boolean {
+export function isDocumentChangeMissingError(err: FirestoreError): boolean {
   return (
     err.code === Code.DATA_LOSS &&
-    err.message === REMOTE_DOCUMENT_CHANGELOG_GARBAGE_COLLECTED_ERR_MSG
+    err.message === REMOTE_DOCUMENT_CHANGE_MISSING_ERR_MSG
   );
 }
 

packages/firestore/src/local/local_store.ts

@@ -869,14 +869,4 @@ export class LocalStore {
       }
     );
   }
-
-  resetLastDocumentChangeId(): Promise<void> {
-    return this.persistence.runTransaction(
-      'Reset last document change ID',
-      'readonly',
-      txn => {
-        return this.remoteDocuments.resetLastProcessedDocumentChange(txn);
-      }
-    );
-  }
 }

packages/firestore/src/local/memory_remote_document_cache.ts

@@ -99,11 +99,4 @@ export class MemoryRemoteDocumentCache implements RemoteDocumentCache {
 
     return PersistencePromise.resolve(changedDocs);
   }
-
-  resetLastProcessedDocumentChange(
-    transaction: PersistenceTransaction
-  ): PersistencePromise<void> {
-    this.newDocumentChanges = documentKeySet();
-    return PersistencePromise.resolve();
-  }
 }

packages/firestore/src/local/remote_document_cache.ts

@@ -89,20 +89,13 @@ export interface RemoteDocumentCache {
    * Returns the set of documents that have been updated since the last call.
    * If this is the first call, returns the set of changes since client
    * initialization.
+   *
+   * If the changelog was garbage collected and can no longer be replayed,
+   * `getNewDocumentChanges` will reject the returned Promise. Further
+   * invocations will return document changes since the point of rejection.
    */
   // PORTING NOTE: This is only used for multi-tab synchronization.
   getNewDocumentChanges(
     transaction: PersistenceTransaction
   ): PersistencePromise<MaybeDocumentMap>;
-
-  /**
-   * Skips all existing change log entries in IndexedDb and moves the change log
-   * cursor past the last existing change. This method should only be called if
-   * `getNewDocumentChanges()`can no longer replay all changes and all views
-   * have already been manually synchronized.
-   */
-  // PORTING NOTE: This is only used for multi-tab synchronization.
-  resetLastProcessedDocumentChange(
-    transaction: PersistenceTransaction
-  ): PersistencePromise<void>;
 }

packages/firestore/test/unit/local/remote_document_cache.test.ts

@@ -30,7 +30,7 @@ import {
 
 import {
   IndexedDbRemoteDocumentCache,
-  isRemoteDocumentChangesGarbageCollectedError
+  isDocumentChangeMissingError
 } from '../../../src/local/indexeddb_remote_document_cache';
 import {
   DbRemoteDocumentChanges,
@@ -155,14 +155,11 @@ describe('IndexedDbRemoteDocumentCache', () => {
       .getNewDocumentChanges()
       .then(
         () => fail('Missing expected error'),
-        err =>
-          expect(isRemoteDocumentChangesGarbageCollectedError(err)).to.be.ok
+        err => expect(isDocumentChangeMissingError(err)).to.be.ok
       );
 
-    // Recover by moving moving the change log cursor to the last existing
-    // entry. We assume that as part of the recovery, all relevant changes have
-    // been processed manually (see `SyncEngine.applyTargetState`).
-    await readerCache.resetLastProcessDocumentChange();
+    // Ensure that we can retrieve future changes after the we processed the
+    // error
     await writerCache.addEntries([doc('a/4', 4, DOC_DATA)]);
     changedDocs = await readerCache.getNewDocumentChanges();
     assertMatches([doc('a/4', 4, DOC_DATA)], changedDocs);

packages/firestore/test/unit/local/test_remote_document_cache.ts

@@ -78,31 +78,17 @@ export class TestRemoteDocumentCache {
     );
   }
 
-  resetLastProcessDocumentChange(): Promise<void> {
-    return this.persistence.runTransaction(
-      'resetLastProcessDocumentChange',
-      'readonly',
-      txn => {
-        return this.cache.resetLastProcessedDocumentChange(txn);
-      }
-    );
-  }
-
   removeDocumentChangesThroughChangeId(changeId: number): Promise<void> {
-    if (!(this.cache instanceof IndexedDbRemoteDocumentCache)) {
-      throw new Error(
-        'Can only removeDocumentChangesThroughChangeId() in IndexedDb'
-      );
-    }
     return this.persistence.runTransaction(
       'removeDocumentChangesThroughChangeId',
       'readwrite-primary',
       txn => {
-        return (this
-          .cache as IndexedDbRemoteDocumentCache).removeDocumentChangesThroughChangeId(
-          txn,
-          changeId
-        );
+        if (!(this.cache instanceof IndexedDbRemoteDocumentCache)) {
+          throw new Error(
+            'Can only removeDocumentChangesThroughChangeId() in IndexedDb'
+          );
+        }
+        return this.cache.removeDocumentChangesThroughChangeId(txn, changeId);
       }
     );
   }