From eb44929efc57836f9e960eb798acb07ea25295a5 Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Fri, 2 Feb 2018 11:44:46 -0800
Subject: [PATCH 01/22] Adding Schema Migration

---
 .../src/local/indexeddb_migrations.ts         | 91 +++++++++++++++++++
 .../src/local/indexeddb_persistence.ts        |  3 +-
 .../firestore/src/local/indexeddb_schema.ts   | 60 +++---------
 3 files changed, 108 insertions(+), 46 deletions(-)
 create mode 100644 packages/firestore/src/local/indexeddb_migrations.ts

diff --git a/packages/firestore/src/local/indexeddb_migrations.ts b/packages/firestore/src/local/indexeddb_migrations.ts
new file mode 100644
index 00000000000..b543fadc8eb
--- /dev/null
+++ b/packages/firestore/src/local/indexeddb_migrations.ts
@@ -0,0 +1,91 @@
+/**
+ * Copyright 2018 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import {
+  DbDocumentMutation, DbInstance,
+  DbMutationBatch, DbMutationQueue, DbOwner, DbRemoteDocument, DbTarget,
+  DbTargetDocument, DbTargetGlobal
+} from './indexeddb_schema';
+import {fail} from '../util/assert';
+
+export function createDb(db: IDBDatabase): void {
+  db.createObjectStore(DbMutationQueue.store, {
+    keyPath: DbMutationQueue.keyPath
+  });
+
+  // TODO(mikelehen): Get rid of "as any" if/when TypeScript fixes their
+  // types. https://github.com/Microsoft/TypeScript/issues/14322
+  db.createObjectStore(
+      DbMutationBatch.store,
+      // tslint:disable-next-line:no-any
+      { keyPath: DbMutationBatch.keyPath as any }
+  );
+
+  const targetDocumentsStore = db.createObjectStore(
+      DbTargetDocument.store,
+      // tslint:disable-next-line:no-any
+      { keyPath: DbTargetDocument.keyPath as any }
+  );
+  targetDocumentsStore.createIndex(
+      DbTargetDocument.documentTargetsIndex,
+      DbTargetDocument.documentTargetsKeyPath,
+      { unique: true }
+  );
+
+  const targetStore = db.createObjectStore(DbTarget.store, {
+    keyPath: DbTarget.keyPath
+  });
+  // NOTE: This is unique only because the TargetId is the suffix.
+  targetStore.createIndex(
+      DbTarget.queryTargetsIndexName,
+      DbTarget.queryTargetsKeyPath,
+      { unique: true }
+  );
+
+  const instanceStore = db.createObjectStore(DbInstance.store, {
+    keyPath: DbInstance.keyPath as any
+  });
+
+  // NOTE: keys for these stores are specified explicitly rather than using a
+  // keyPath.
+  db.createObjectStore(DbDocumentMutation.store);
+  db.createObjectStore(DbRemoteDocument.store);
+  db.createObjectStore(DbOwner.store);
+  db.createObjectStore(DbTargetGlobal.store);
+}
+
+export function upgradeDbFromV1(db: IDBDatabase): void {
+
+}
+
+export class IndexedDbMigrations {
+  /**
+   * Runs any migrations needed to bring the given database up to the current
+   * schema version.
+   */
+  static runMigrations(db: IDBDatabase, oldVersion: number) {
+    if (oldVersion == 0) {
+      createDb(db, oldVersion);
+      return;
+    }
+
+    if (oldVersion == 1) {
+      upgradeDbFromV1(db, oldVersion);
+      return;
+    }
+
+    fail('Unexpected upgrade from version ' + oldVersion);
+  }
+}
\ No newline at end of file
diff --git a/packages/firestore/src/local/indexeddb_persistence.ts b/packages/firestore/src/local/indexeddb_persistence.ts
index c4bcd5c8634..298ef5c6879 100644
--- a/packages/firestore/src/local/indexeddb_persistence.ts
+++ b/packages/firestore/src/local/indexeddb_persistence.ts
@@ -34,6 +34,7 @@ import { PersistencePromise } from './persistence_promise';
 import { QueryCache } from './query_cache';
 import { RemoteDocumentCache } from './remote_document_cache';
 import { SimpleDb, SimpleDbTransaction } from './simple_db';
+import {IndexedDbMigrations} from './indexeddb_migrations';
 
 const LOG_TAG = 'IndexedDbPersistence';
 
@@ -127,7 +128,7 @@ export class IndexedDbPersistence implements Persistence {
     assert(!this.started, 'IndexedDbPersistence double-started!');
     this.started = true;
 
-    return SimpleDb.openOrCreate(this.dbName, SCHEMA_VERSION, createOrUpgradeDb)
+    return SimpleDb.openOrCreate(this.dbName, SCHEMA_VERSION, IndexedDbMigrations.runMigrations)
       .then(db => {
         this.simpleDb = db;
       })
diff --git a/packages/firestore/src/local/indexeddb_schema.ts b/packages/firestore/src/local/indexeddb_schema.ts
index 88bfb484371..a7808dbfbc7 100644
--- a/packages/firestore/src/local/indexeddb_schema.ts
+++ b/packages/firestore/src/local/indexeddb_schema.ts
@@ -24,51 +24,6 @@ import { encode, EncodedResourcePath } from './encoded_resource_path';
 
 export const SCHEMA_VERSION = 1;
 
-/** Performs database creation and (in the future) upgrades between versions. */
-export function createOrUpgradeDb(db: IDBDatabase, oldVersion: number): void {
-  assert(oldVersion === 0, 'Unexpected upgrade from version ' + oldVersion);
-
-  db.createObjectStore(DbMutationQueue.store, {
-    keyPath: DbMutationQueue.keyPath
-  });
-
-  // TODO(mikelehen): Get rid of "as any" if/when TypeScript fixes their
-  // types. https://github.com/Microsoft/TypeScript/issues/14322
-  db.createObjectStore(
-    DbMutationBatch.store,
-    // tslint:disable-next-line:no-any
-    { keyPath: DbMutationBatch.keyPath as any }
-  );
-
-  const targetDocumentsStore = db.createObjectStore(
-    DbTargetDocument.store,
-    // tslint:disable-next-line:no-any
-    { keyPath: DbTargetDocument.keyPath as any }
-  );
-  targetDocumentsStore.createIndex(
-    DbTargetDocument.documentTargetsIndex,
-    DbTargetDocument.documentTargetsKeyPath,
-    { unique: true }
-  );
-
-  const targetStore = db.createObjectStore(DbTarget.store, {
-    keyPath: DbTarget.keyPath
-  });
-  // NOTE: This is unique only because the TargetId is the suffix.
-  targetStore.createIndex(
-    DbTarget.queryTargetsIndexName,
-    DbTarget.queryTargetsKeyPath,
-    { unique: true }
-  );
-
-  // NOTE: keys for these stores are specified explicitly rather than using a
-  // keyPath.
-  db.createObjectStore(DbDocumentMutation.store);
-  db.createObjectStore(DbRemoteDocument.store);
-  db.createObjectStore(DbOwner.store);
-  db.createObjectStore(DbTargetGlobal.store);
-}
-
 /**
  * Wrapper class to store timestamps (seconds and nanos) in IndexedDb objects.
  */
@@ -455,6 +410,21 @@ export class DbTargetGlobal {
   ) {}
 }
 
+export type DbInstanceKey = [string, string];
+
+export class DbInstance {
+  static store = 'instances';
+
+  static keyPath = ['userId', 'instanceId'];
+
+  constructor(
+      public userId: string,
+      public instanceId: string,
+      public updateTimeMs: number,
+      public visibilityState: VisibilityState
+  ) {}
+}
+
 /**
  * The list of all IndexedDB stored used by the SDK. This is used when creating
  * transactions so that access across all stores is done atomically.

From 07e44e7e80167c0d25a40e9c8cc03290c222141f Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Fri, 2 Feb 2018 13:54:02 -0800
Subject: [PATCH 02/22] Pseudocode for Schema Migration

---
 .../src/local/indexeddb_migrations.ts         | 95 +++++++++++--------
 .../src/local/indexeddb_persistence.ts        |  6 +-
 .../firestore/src/local/indexeddb_schema.ts   | 23 +++--
 packages/firestore/src/local/simple_db.ts     |  5 +-
 4 files changed, 80 insertions(+), 49 deletions(-)

diff --git a/packages/firestore/src/local/indexeddb_migrations.ts b/packages/firestore/src/local/indexeddb_migrations.ts
index b543fadc8eb..98c3fba0a65 100644
--- a/packages/firestore/src/local/indexeddb_migrations.ts
+++ b/packages/firestore/src/local/indexeddb_migrations.ts
@@ -15,28 +15,20 @@
  */
 import {
   DbDocumentMutation, DbInstance,
-  DbMutationBatch, DbMutationQueue, DbOwner, DbRemoteDocument, DbTarget,
+  DbMutationBatch, DbMutationQueue, DbOwner,
+  DbRemoteDocument, DbTarget,
   DbTargetDocument, DbTargetGlobal
 } from './indexeddb_schema';
-import {fail} from '../util/assert';
+import {assert, fail} from '../util/assert';
 
-export function createDb(db: IDBDatabase): void {
-  db.createObjectStore(DbMutationQueue.store, {
-    keyPath: DbMutationQueue.keyPath
-  });
-
-  // TODO(mikelehen): Get rid of "as any" if/when TypeScript fixes their
-  // types. https://github.com/Microsoft/TypeScript/issues/14322
-  db.createObjectStore(
-      DbMutationBatch.store,
-      // tslint:disable-next-line:no-any
-      { keyPath: DbMutationBatch.keyPath as any }
-  );
+// TODO(mikelehen): Get rid of "as any" if/when TypeScript fixes their types.
+// https://github.com/Microsoft/TypeScript/issues/14322
+type KeyPath = any; // tslint:disable-line:no-any
 
+function createCache(db: IDBDatabase): void {
   const targetDocumentsStore = db.createObjectStore(
       DbTargetDocument.store,
-      // tslint:disable-next-line:no-any
-      { keyPath: DbTargetDocument.keyPath as any }
+      { keyPath: DbTargetDocument.keyPath as KeyPath }
   );
   targetDocumentsStore.createIndex(
       DbTargetDocument.documentTargetsIndex,
@@ -47,45 +39,72 @@ export function createDb(db: IDBDatabase): void {
   const targetStore = db.createObjectStore(DbTarget.store, {
     keyPath: DbTarget.keyPath
   });
+
   // NOTE: This is unique only because the TargetId is the suffix.
   targetStore.createIndex(
       DbTarget.queryTargetsIndexName,
       DbTarget.queryTargetsKeyPath,
       { unique: true }
   );
+  db.createObjectStore(DbRemoteDocument.store);
+  db.createObjectStore(DbTargetGlobal.store);
+}
+
+function dropCache(db: IDBDatabase): void {
+  db.deleteObjectStore(DbTargetDocument.store);
+  db.deleteObjectStore(DbTarget.keyPath);
+  db.deleteObjectStore(DbRemoteDocument.store);
+  db.deleteObjectStore(DbTargetGlobal.store);
+}
 
-  const instanceStore = db.createObjectStore(DbInstance.store, {
-    keyPath: DbInstance.keyPath as any
+function createOwnerStore(db: IDBDatabase) : void {
+  db.createObjectStore(DbOwner.store);
+}
+
+function createInstanceStore(db: IDBDatabase) : void {
+  db.createObjectStore(DbInstance.store, {
+    keyPath: DbInstance.keyPath as KeyPath
   });
+}
+
+function createMutationQueue(db: IDBDatabase) : void {
+  db.createObjectStore(DbMutationQueue.store, {
+    keyPath: DbMutationQueue.keyPath
+  });
+
+  db.createObjectStore(
+      DbMutationBatch.store,
+      { keyPath: DbMutationBatch.keyPath as KeyPath }
+  );
 
   // NOTE: keys for these stores are specified explicitly rather than using a
   // keyPath.
   db.createObjectStore(DbDocumentMutation.store);
-  db.createObjectStore(DbRemoteDocument.store);
-  db.createObjectStore(DbOwner.store);
-  db.createObjectStore(DbTargetGlobal.store);
 }
 
-export function upgradeDbFromV1(db: IDBDatabase): void {
+/**
+ * Runs any migrations needed to bring the given database up to the current
+ * schema version.
+ */
+export function createOrUpgradeDb(db: IDBDatabase, oldVersion: number, newVersion: number): void   {
+  assert(oldVersion >= 0 || oldVersion <= 1, 'Unexpected upgrade from version ' + oldVersion);
+  assert(newVersion >= 1 || newVersion <= 2, 'Unexpected upgrade to version ' + newVersion);
 
-}
+  const createV1 = newVersion >= 1 && oldVersion <= 1;
+  const dropV1 = oldVersion >= 1;
+  const createV2 = newVersion >= 2 && oldVersion <= 2;
 
-export class IndexedDbMigrations {
-  /**
-   * Runs any migrations needed to bring the given database up to the current
-   * schema version.
-   */
-  static runMigrations(db: IDBDatabase, oldVersion: number) {
-    if (oldVersion == 0) {
-      createDb(db, oldVersion);
-      return;
-    }
+  if (dropV1) {
+    dropCache(db);
+  }
 
-    if (oldVersion == 1) {
-      upgradeDbFromV1(db, oldVersion);
-      return;
-    }
+  if (createV1) {
+    createOwnerStore(db);
+    createMutationQueue(db);
+    createCache(db);
+  }
 
-    fail('Unexpected upgrade from version ' + oldVersion);
+  if (createV2) {
+    createInstanceStore(db);
   }
 }
\ No newline at end of file
diff --git a/packages/firestore/src/local/indexeddb_persistence.ts b/packages/firestore/src/local/indexeddb_persistence.ts
index 298ef5c6879..54abbdb40ae 100644
--- a/packages/firestore/src/local/indexeddb_persistence.ts
+++ b/packages/firestore/src/local/indexeddb_persistence.ts
@@ -26,7 +26,7 @@ import { IndexedDbMutationQueue } from './indexeddb_mutation_queue';
 import { IndexedDbQueryCache } from './indexeddb_query_cache';
 import { IndexedDbRemoteDocumentCache } from './indexeddb_remote_document_cache';
 import { ALL_STORES, DbOwner, DbOwnerKey } from './indexeddb_schema';
-import { createOrUpgradeDb, SCHEMA_VERSION } from './indexeddb_schema';
+import { SCHEMA_VERSION } from './indexeddb_schema';
 import { LocalSerializer } from './local_serializer';
 import { MutationQueue } from './mutation_queue';
 import { Persistence } from './persistence';
@@ -34,7 +34,7 @@ import { PersistencePromise } from './persistence_promise';
 import { QueryCache } from './query_cache';
 import { RemoteDocumentCache } from './remote_document_cache';
 import { SimpleDb, SimpleDbTransaction } from './simple_db';
-import {IndexedDbMigrations} from './indexeddb_migrations';
+import {createOrUpgradeDb} from './indexeddb_migrations';
 
 const LOG_TAG = 'IndexedDbPersistence';
 
@@ -128,7 +128,7 @@ export class IndexedDbPersistence implements Persistence {
     assert(!this.started, 'IndexedDbPersistence double-started!');
     this.started = true;
 
-    return SimpleDb.openOrCreate(this.dbName, SCHEMA_VERSION, IndexedDbMigrations.runMigrations)
+    return SimpleDb.openOrCreate(this.dbName, SCHEMA_VERSION, createOrUpgradeDb)
       .then(db => {
         this.simpleDb = db;
       })
diff --git a/packages/firestore/src/local/indexeddb_schema.ts b/packages/firestore/src/local/indexeddb_schema.ts
index a7808dbfbc7..4e147bbea22 100644
--- a/packages/firestore/src/local/indexeddb_schema.ts
+++ b/packages/firestore/src/local/indexeddb_schema.ts
@@ -21,6 +21,7 @@ import { ResourcePath } from '../model/path';
 import { assert } from '../util/assert';
 
 import { encode, EncodedResourcePath } from './encoded_resource_path';
+import {SnapshotVersion} from '../core/snapshot_version';
 
 export const SCHEMA_VERSION = 1;
 
@@ -86,7 +87,15 @@ export class DbMutationQueue {
      * After sending this token, earlier tokens may not be used anymore so
      * only a single stream token is retained.
      */
-    public lastStreamToken: string
+    public lastStreamToken: string,
+
+    /**
+     * An identifier for the highest numbered batch that has been acknowledged
+     * by the server. All MutationBatches in this queue with batchIds less
+     * than or equal to this value are considered to have been acknowledged by
+     * the server.
+     */
+    public highestPendingBatchId: number,
   ) {}
 }
 
@@ -345,8 +354,8 @@ export class DbTargetDocument {
   /** Name of the IndexedDb object store.  */
   static store = 'targetDocuments';
 
-  /** Keys are automatically assigned via the targetId, path properties. */
-  static keyPath = ['targetId', 'path'];
+  /** Keys are automatically assigned via the targetId, snapshotVersion, and path properties. */
+  static keyPath = ['targetId', 'snapshotVersion', 'path'];
 
   /** The index name for the reverse index. */
   static documentTargetsIndex = 'documentTargetsIndex';
@@ -359,6 +368,8 @@ export class DbTargetDocument {
      * The targetId identifying a target.
      */
     public targetId: TargetId,
+
+    public snapshotVersion: number,
     /**
      * The path to the document, as encoded in the key.
      */
@@ -420,8 +431,7 @@ export class DbInstance {
   constructor(
       public userId: string,
       public instanceId: string,
-      public updateTimeMs: number,
-      public visibilityState: VisibilityState
+      public updateTimeMs: number
   ) {}
 }
 
@@ -437,5 +447,6 @@ export const ALL_STORES = [
   DbTarget.store,
   DbOwner.store,
   DbTargetGlobal.store,
-  DbTargetDocument.store
+  DbTargetDocument.store,
+  DbInstance.store
 ];
diff --git a/packages/firestore/src/local/simple_db.ts b/packages/firestore/src/local/simple_db.ts
index cfaa6bb9767..2a925ead624 100644
--- a/packages/firestore/src/local/simple_db.ts
+++ b/packages/firestore/src/local/simple_db.ts
@@ -19,6 +19,7 @@ import { debug } from '../util/log';
 import { AnyDuringMigration } from '../util/misc';
 
 import { PersistencePromise } from './persistence_promise';
+import {SCHEMA_VERSION} from './indexeddb_schema';
 
 const LOG_TAG = 'SimpleDb';
 
@@ -34,7 +35,7 @@ export class SimpleDb {
   static openOrCreate(
     name: string,
     version: number,
-    runUpgrade: (db: IDBDatabase, oldVersion: number) => void
+    runUpgrade: (db: IDBDatabase, oldVersion: number, newVersion: number) => void
   ): Promise<SimpleDb> {
     assert(
       SimpleDb.isAvailable(),
@@ -70,7 +71,7 @@ export class SimpleDb {
         // cheating and just passing the raw IndexedDB in, since
         // createObjectStore(), etc. are synchronous.
         const db = (event.target as IDBOpenDBRequest).result;
-        runUpgrade(db, event.oldVersion);
+        runUpgrade(db, event.oldVersion, SCHEMA_VERSION);
       };
     }).toPromise();
   }

From 3e1053f5e683c5e5b95f6bf42ef64c5982f7c51a Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Fri, 2 Feb 2018 13:54:29 -0800
Subject: [PATCH 03/22] [AUTOMATED]: Prettier Code Styling

---
 .../src/local/indexeddb_migrations.ts         | 65 +++++++++++--------
 .../src/local/indexeddb_persistence.ts        |  2 +-
 .../firestore/src/local/indexeddb_schema.ts   | 12 ++--
 packages/firestore/src/local/simple_db.ts     |  8 ++-
 4 files changed, 51 insertions(+), 36 deletions(-)

diff --git a/packages/firestore/src/local/indexeddb_migrations.ts b/packages/firestore/src/local/indexeddb_migrations.ts
index 98c3fba0a65..faac5951c44 100644
--- a/packages/firestore/src/local/indexeddb_migrations.ts
+++ b/packages/firestore/src/local/indexeddb_migrations.ts
@@ -14,26 +14,30 @@
  * limitations under the License.
  */
 import {
-  DbDocumentMutation, DbInstance,
-  DbMutationBatch, DbMutationQueue, DbOwner,
-  DbRemoteDocument, DbTarget,
-  DbTargetDocument, DbTargetGlobal
+  DbDocumentMutation,
+  DbInstance,
+  DbMutationBatch,
+  DbMutationQueue,
+  DbOwner,
+  DbRemoteDocument,
+  DbTarget,
+  DbTargetDocument,
+  DbTargetGlobal
 } from './indexeddb_schema';
-import {assert, fail} from '../util/assert';
+import { assert, fail } from '../util/assert';
 
 // TODO(mikelehen): Get rid of "as any" if/when TypeScript fixes their types.
 // https://github.com/Microsoft/TypeScript/issues/14322
 type KeyPath = any; // tslint:disable-line:no-any
 
 function createCache(db: IDBDatabase): void {
-  const targetDocumentsStore = db.createObjectStore(
-      DbTargetDocument.store,
-      { keyPath: DbTargetDocument.keyPath as KeyPath }
-  );
+  const targetDocumentsStore = db.createObjectStore(DbTargetDocument.store, {
+    keyPath: DbTargetDocument.keyPath as KeyPath
+  });
   targetDocumentsStore.createIndex(
-      DbTargetDocument.documentTargetsIndex,
-      DbTargetDocument.documentTargetsKeyPath,
-      { unique: true }
+    DbTargetDocument.documentTargetsIndex,
+    DbTargetDocument.documentTargetsKeyPath,
+    { unique: true }
   );
 
   const targetStore = db.createObjectStore(DbTarget.store, {
@@ -42,9 +46,9 @@ function createCache(db: IDBDatabase): void {
 
   // NOTE: This is unique only because the TargetId is the suffix.
   targetStore.createIndex(
-      DbTarget.queryTargetsIndexName,
-      DbTarget.queryTargetsKeyPath,
-      { unique: true }
+    DbTarget.queryTargetsIndexName,
+    DbTarget.queryTargetsKeyPath,
+    { unique: true }
   );
   db.createObjectStore(DbRemoteDocument.store);
   db.createObjectStore(DbTargetGlobal.store);
@@ -57,25 +61,24 @@ function dropCache(db: IDBDatabase): void {
   db.deleteObjectStore(DbTargetGlobal.store);
 }
 
-function createOwnerStore(db: IDBDatabase) : void {
+function createOwnerStore(db: IDBDatabase): void {
   db.createObjectStore(DbOwner.store);
 }
 
-function createInstanceStore(db: IDBDatabase) : void {
+function createInstanceStore(db: IDBDatabase): void {
   db.createObjectStore(DbInstance.store, {
     keyPath: DbInstance.keyPath as KeyPath
   });
 }
 
-function createMutationQueue(db: IDBDatabase) : void {
+function createMutationQueue(db: IDBDatabase): void {
   db.createObjectStore(DbMutationQueue.store, {
     keyPath: DbMutationQueue.keyPath
   });
 
-  db.createObjectStore(
-      DbMutationBatch.store,
-      { keyPath: DbMutationBatch.keyPath as KeyPath }
-  );
+  db.createObjectStore(DbMutationBatch.store, {
+    keyPath: DbMutationBatch.keyPath as KeyPath
+  });
 
   // NOTE: keys for these stores are specified explicitly rather than using a
   // keyPath.
@@ -86,9 +89,19 @@ function createMutationQueue(db: IDBDatabase) : void {
  * Runs any migrations needed to bring the given database up to the current
  * schema version.
  */
-export function createOrUpgradeDb(db: IDBDatabase, oldVersion: number, newVersion: number): void   {
-  assert(oldVersion >= 0 || oldVersion <= 1, 'Unexpected upgrade from version ' + oldVersion);
-  assert(newVersion >= 1 || newVersion <= 2, 'Unexpected upgrade to version ' + newVersion);
+export function createOrUpgradeDb(
+  db: IDBDatabase,
+  oldVersion: number,
+  newVersion: number
+): void {
+  assert(
+    oldVersion >= 0 || oldVersion <= 1,
+    'Unexpected upgrade from version ' + oldVersion
+  );
+  assert(
+    newVersion >= 1 || newVersion <= 2,
+    'Unexpected upgrade to version ' + newVersion
+  );
 
   const createV1 = newVersion >= 1 && oldVersion <= 1;
   const dropV1 = oldVersion >= 1;
@@ -107,4 +120,4 @@ export function createOrUpgradeDb(db: IDBDatabase, oldVersion: number, newVersio
   if (createV2) {
     createInstanceStore(db);
   }
-}
\ No newline at end of file
+}
diff --git a/packages/firestore/src/local/indexeddb_persistence.ts b/packages/firestore/src/local/indexeddb_persistence.ts
index 54abbdb40ae..6b7f5b26c7e 100644
--- a/packages/firestore/src/local/indexeddb_persistence.ts
+++ b/packages/firestore/src/local/indexeddb_persistence.ts
@@ -34,7 +34,7 @@ import { PersistencePromise } from './persistence_promise';
 import { QueryCache } from './query_cache';
 import { RemoteDocumentCache } from './remote_document_cache';
 import { SimpleDb, SimpleDbTransaction } from './simple_db';
-import {createOrUpgradeDb} from './indexeddb_migrations';
+import { createOrUpgradeDb } from './indexeddb_migrations';
 
 const LOG_TAG = 'IndexedDbPersistence';
 
diff --git a/packages/firestore/src/local/indexeddb_schema.ts b/packages/firestore/src/local/indexeddb_schema.ts
index 4e147bbea22..619b175a6b8 100644
--- a/packages/firestore/src/local/indexeddb_schema.ts
+++ b/packages/firestore/src/local/indexeddb_schema.ts
@@ -21,7 +21,7 @@ import { ResourcePath } from '../model/path';
 import { assert } from '../util/assert';
 
 import { encode, EncodedResourcePath } from './encoded_resource_path';
-import {SnapshotVersion} from '../core/snapshot_version';
+import { SnapshotVersion } from '../core/snapshot_version';
 
 export const SCHEMA_VERSION = 1;
 
@@ -88,14 +88,13 @@ export class DbMutationQueue {
      * only a single stream token is retained.
      */
     public lastStreamToken: string,
-
     /**
      * An identifier for the highest numbered batch that has been acknowledged
      * by the server. All MutationBatches in this queue with batchIds less
      * than or equal to this value are considered to have been acknowledged by
      * the server.
      */
-    public highestPendingBatchId: number,
+    public highestPendingBatchId: number
   ) {}
 }
 
@@ -368,7 +367,6 @@ export class DbTargetDocument {
      * The targetId identifying a target.
      */
     public targetId: TargetId,
-
     public snapshotVersion: number,
     /**
      * The path to the document, as encoded in the key.
@@ -429,9 +427,9 @@ export class DbInstance {
   static keyPath = ['userId', 'instanceId'];
 
   constructor(
-      public userId: string,
-      public instanceId: string,
-      public updateTimeMs: number
+    public userId: string,
+    public instanceId: string,
+    public updateTimeMs: number
   ) {}
 }
 
diff --git a/packages/firestore/src/local/simple_db.ts b/packages/firestore/src/local/simple_db.ts
index 2a925ead624..c7f7ff87d98 100644
--- a/packages/firestore/src/local/simple_db.ts
+++ b/packages/firestore/src/local/simple_db.ts
@@ -19,7 +19,7 @@ import { debug } from '../util/log';
 import { AnyDuringMigration } from '../util/misc';
 
 import { PersistencePromise } from './persistence_promise';
-import {SCHEMA_VERSION} from './indexeddb_schema';
+import { SCHEMA_VERSION } from './indexeddb_schema';
 
 const LOG_TAG = 'SimpleDb';
 
@@ -35,7 +35,11 @@ export class SimpleDb {
   static openOrCreate(
     name: string,
     version: number,
-    runUpgrade: (db: IDBDatabase, oldVersion: number, newVersion: number) => void
+    runUpgrade: (
+      db: IDBDatabase,
+      oldVersion: number,
+      newVersion: number
+    ) => void
   ): Promise<SimpleDb> {
     assert(
       SimpleDb.isAvailable(),

From 5e8478245bf434f96d3e81deca7d13ffc9e2bbc1 Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Sun, 4 Feb 2018 20:15:54 -0800
Subject: [PATCH 04/22] IndexedDb Schema Migration

---
 .../src/local/indexeddb_migrations.ts         | 123 --------
 .../src/local/indexeddb_persistence.ts        |  10 +-
 .../firestore/src/local/indexeddb_schema.ts   | 264 ++++++++++++++----
 packages/firestore/src/local/simple_db.ts     |   4 +-
 .../test/unit/local/schema_migration.test.ts  | 107 +++++++
 5 files changed, 320 insertions(+), 188 deletions(-)
 delete mode 100644 packages/firestore/src/local/indexeddb_migrations.ts
 create mode 100644 packages/firestore/test/unit/local/schema_migration.test.ts

diff --git a/packages/firestore/src/local/indexeddb_migrations.ts b/packages/firestore/src/local/indexeddb_migrations.ts
deleted file mode 100644
index faac5951c44..00000000000
--- a/packages/firestore/src/local/indexeddb_migrations.ts
+++ /dev/null
@@ -1,123 +0,0 @@
-/**
- * Copyright 2018 Google Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-import {
-  DbDocumentMutation,
-  DbInstance,
-  DbMutationBatch,
-  DbMutationQueue,
-  DbOwner,
-  DbRemoteDocument,
-  DbTarget,
-  DbTargetDocument,
-  DbTargetGlobal
-} from './indexeddb_schema';
-import { assert, fail } from '../util/assert';
-
-// TODO(mikelehen): Get rid of "as any" if/when TypeScript fixes their types.
-// https://github.com/Microsoft/TypeScript/issues/14322
-type KeyPath = any; // tslint:disable-line:no-any
-
-function createCache(db: IDBDatabase): void {
-  const targetDocumentsStore = db.createObjectStore(DbTargetDocument.store, {
-    keyPath: DbTargetDocument.keyPath as KeyPath
-  });
-  targetDocumentsStore.createIndex(
-    DbTargetDocument.documentTargetsIndex,
-    DbTargetDocument.documentTargetsKeyPath,
-    { unique: true }
-  );
-
-  const targetStore = db.createObjectStore(DbTarget.store, {
-    keyPath: DbTarget.keyPath
-  });
-
-  // NOTE: This is unique only because the TargetId is the suffix.
-  targetStore.createIndex(
-    DbTarget.queryTargetsIndexName,
-    DbTarget.queryTargetsKeyPath,
-    { unique: true }
-  );
-  db.createObjectStore(DbRemoteDocument.store);
-  db.createObjectStore(DbTargetGlobal.store);
-}
-
-function dropCache(db: IDBDatabase): void {
-  db.deleteObjectStore(DbTargetDocument.store);
-  db.deleteObjectStore(DbTarget.keyPath);
-  db.deleteObjectStore(DbRemoteDocument.store);
-  db.deleteObjectStore(DbTargetGlobal.store);
-}
-
-function createOwnerStore(db: IDBDatabase): void {
-  db.createObjectStore(DbOwner.store);
-}
-
-function createInstanceStore(db: IDBDatabase): void {
-  db.createObjectStore(DbInstance.store, {
-    keyPath: DbInstance.keyPath as KeyPath
-  });
-}
-
-function createMutationQueue(db: IDBDatabase): void {
-  db.createObjectStore(DbMutationQueue.store, {
-    keyPath: DbMutationQueue.keyPath
-  });
-
-  db.createObjectStore(DbMutationBatch.store, {
-    keyPath: DbMutationBatch.keyPath as KeyPath
-  });
-
-  // NOTE: keys for these stores are specified explicitly rather than using a
-  // keyPath.
-  db.createObjectStore(DbDocumentMutation.store);
-}
-
-/**
- * Runs any migrations needed to bring the given database up to the current
- * schema version.
- */
-export function createOrUpgradeDb(
-  db: IDBDatabase,
-  oldVersion: number,
-  newVersion: number
-): void {
-  assert(
-    oldVersion >= 0 || oldVersion <= 1,
-    'Unexpected upgrade from version ' + oldVersion
-  );
-  assert(
-    newVersion >= 1 || newVersion <= 2,
-    'Unexpected upgrade to version ' + newVersion
-  );
-
-  const createV1 = newVersion >= 1 && oldVersion <= 1;
-  const dropV1 = oldVersion >= 1;
-  const createV2 = newVersion >= 2 && oldVersion <= 2;
-
-  if (dropV1) {
-    dropCache(db);
-  }
-
-  if (createV1) {
-    createOwnerStore(db);
-    createMutationQueue(db);
-    createCache(db);
-  }
-
-  if (createV2) {
-    createInstanceStore(db);
-  }
-}
diff --git a/packages/firestore/src/local/indexeddb_persistence.ts b/packages/firestore/src/local/indexeddb_persistence.ts
index 6b7f5b26c7e..b09548e5e2b 100644
--- a/packages/firestore/src/local/indexeddb_persistence.ts
+++ b/packages/firestore/src/local/indexeddb_persistence.ts
@@ -25,8 +25,13 @@ import { AutoId } from '../util/misc';
 import { IndexedDbMutationQueue } from './indexeddb_mutation_queue';
 import { IndexedDbQueryCache } from './indexeddb_query_cache';
 import { IndexedDbRemoteDocumentCache } from './indexeddb_remote_document_cache';
-import { ALL_STORES, DbOwner, DbOwnerKey } from './indexeddb_schema';
-import { SCHEMA_VERSION } from './indexeddb_schema';
+import {
+  ALL_STORES,
+  createOrUpgradeDb,
+  DbOwner,
+  DbOwnerKey,
+  SCHEMA_VERSION
+} from './indexeddb_schema';
 import { LocalSerializer } from './local_serializer';
 import { MutationQueue } from './mutation_queue';
 import { Persistence } from './persistence';
@@ -34,7 +39,6 @@ import { PersistencePromise } from './persistence_promise';
 import { QueryCache } from './query_cache';
 import { RemoteDocumentCache } from './remote_document_cache';
 import { SimpleDb, SimpleDbTransaction } from './simple_db';
-import { createOrUpgradeDb } from './indexeddb_migrations';
 
 const LOG_TAG = 'IndexedDbPersistence';
 
diff --git a/packages/firestore/src/local/indexeddb_schema.ts b/packages/firestore/src/local/indexeddb_schema.ts
index 619b175a6b8..89a0fb4f817 100644
--- a/packages/firestore/src/local/indexeddb_schema.ts
+++ b/packages/firestore/src/local/indexeddb_schema.ts
@@ -21,9 +21,38 @@ import { ResourcePath } from '../model/path';
 import { assert } from '../util/assert';
 
 import { encode, EncodedResourcePath } from './encoded_resource_path';
-import { SnapshotVersion } from '../core/snapshot_version';
 
-export const SCHEMA_VERSION = 1;
+export const SCHEMA_VERSION = 2;
+
+/**
+ * Performs database creation and schema migrations up to schema version 2.
+ */
+export function createOrUpgradeDb(
+  db: IDBDatabase,
+  fromVersion: number,
+  toVersion: number
+): void {
+  assert(
+    fromVersion < toVersion && fromVersion >= 0 && toVersion <= 2,
+    'Unexpected schema upgrade from v${fromVersion} to v{toVersion}.'
+  );
+
+  if (toVersion === 2) {
+    createInstanceMetadataStore(db);
+    createTargetChangeStore(db);
+  }
+
+  if (fromVersion == 0 && toVersion >= 1) {
+    createOwnerStore(db);
+    createMutationQueue(db);
+    createQueryCache(db);
+    createRemoteDocumentCache(db);
+  }
+}
+
+// TODO(mikelehen): Get rid of "as any" if/when TypeScript fixes their types.
+// https://github.com/Microsoft/TypeScript/issues/14322
+type KeyPath = any; // tslint:disable-line:no-any
 
 /**
  * Wrapper class to store timestamps (seconds and nanos) in IndexedDb objects.
@@ -50,6 +79,10 @@ export class DbOwner {
   constructor(public ownerId: string, public leaseTimestampMs: number) {}
 }
 
+function createOwnerStore(db: IDBDatabase): void {
+  db.createObjectStore(DbOwner.store);
+}
+
 /** Object keys in the 'mutationQueues' store are userId strings. */
 export type DbMutationQueueKey = string;
 
@@ -68,18 +101,19 @@ export class DbMutationQueue {
 
   constructor(
     /**
-     * The normalized user ID to which this queue belongs.
+     * @param userId - The normalized user ID to which this queue belongs.
      */
     public userId: string,
     /**
-     * An identifier for the highest numbered batch that has been acknowledged
-     * by the server. All MutationBatches in this queue with batchIds less
-     * than or equal to this value are considered to have been acknowledged by
-     * the server.
+     * @param lastAcknowledgedBatchId - An identifier for the highest numbered
+     * batch that has been acknowledged by the server. All MutationBatches in
+     * this queue with batchIds less than or equal to this value are considered
+     * to have been acknowledged by the server.
      */
     public lastAcknowledgedBatchId: number,
     /**
-     * A stream token that was previously sent by the server.
+     * @param lastStreamToken - A stream token that was previously sent by the
+     * server.
      *
      * See StreamingWriteRequest in datastore.proto for more details about
      * usage.
@@ -89,10 +123,11 @@ export class DbMutationQueue {
      */
     public lastStreamToken: string,
     /**
-     * An identifier for the highest numbered batch that has been acknowledged
-     * by the server. All MutationBatches in this queue with batchIds less
-     * than or equal to this value are considered to have been acknowledged by
-     * the server.
+     * @param highestPendingBatchId - An identifier for the highest numbered
+     * batch in the mutation queue. This allows for efficient insert of new
+     * batches without relying on in-memory state.
+     *
+     * PORTING NOTE: iOS and Android clients keep this value in-memory.
      */
     public highestPendingBatchId: number
   ) {}
@@ -117,21 +152,22 @@ export class DbMutationBatch {
 
   constructor(
     /**
-     * The normalized user ID to which this batch belongs.
+     * @userId userId - The normalized user ID to which this batch belongs.
      */
     public userId: string,
     /**
-     * An identifier for this batch, allocated by the mutation queue in a
-     * monotonically increasing manner.
+     * @batchId batchId - An identifier for this batch, allocated by the
+     * mutation queue in a monotonically increasing manner.
      */
     public batchId: BatchId,
     /**
-     * The local write time of the batch, stored as milliseconds since the
-     * epoch.
+     * @param localWriteTimeMs - The local write time of the batch, stored as
+     * milliseconds since the epoch.
      */
     public localWriteTimeMs: number,
     /**
-     * A list of mutations to apply. All mutations will be applied atomically.
+     * @param mutations - A list of mutations to apply. All mutations will be
+     * applied atomically.
      *
      * Mutations are serialized via JsonProtoSerializer.toMutation().
      */
@@ -146,6 +182,20 @@ export class DbMutationBatch {
  */
 export type DbDocumentMutationKey = [string, EncodedResourcePath, BatchId];
 
+function createMutationQueue(db: IDBDatabase): void {
+  db.createObjectStore(DbMutationQueue.store, {
+    keyPath: DbMutationQueue.keyPath
+  });
+
+  db.createObjectStore(DbMutationBatch.store, {
+    keyPath: DbMutationBatch.keyPath as KeyPath
+  });
+
+  // NOTE: keys for these stores are specified explicitly rather than using a
+  // keyPath.
+  db.createObjectStore(DbDocumentMutation.store);
+}
+
 /**
  * An object to be stored in the 'documentMutations' store in IndexedDb.
  *
@@ -204,6 +254,10 @@ export class DbDocumentMutation {
  */
 export type DbRemoteDocumentKey = string[];
 
+function createRemoteDocumentCache(db: IDBDatabase): void {
+  db.createObjectStore(DbRemoteDocument.store);
+}
+
 /**
  * Represents the known absence of a document at a particular version.
  * Stored in IndexedDb as part of a DbRemoteDocument object.
@@ -225,13 +279,13 @@ export class DbRemoteDocument {
 
   constructor(
     /**
-     * Set to an instance of a DbNoDocument if it is known that no document
-     * exists.
+     * @param noDocument - Set to an instance of a DbNoDocument if it is known
+     * that no document exists.
      */
     public noDocument: DbNoDocument | null,
     /**
-     * Set to an instance of a Document if there's a cached version of the
-     * document.
+     * @param document - Set to an instance of a Document if there's a cached
+     * version of the document.
      */
     public document: api.Document | null
   ) {}
@@ -276,7 +330,8 @@ export class DbTarget {
 
   constructor(
     /**
-     * An auto-generated sequential numeric identifier for the query.
+     * @param targetId - An auto-generated sequential numeric identifier for the
+     * query.
      *
      * Queries are stored using their canonicalId as the key, but these
      * canonicalIds can be quite long so we additionally assign a unique
@@ -285,20 +340,23 @@ export class DbTarget {
      */
     public targetId: TargetId,
     /**
-     * The canonical string representing this query. This is not unique.
+     * @param canonicalId - The canonical string representing this query. This
+     * is not unique.
      */
     public canonicalId: string,
     /**
-     * The last readTime received from the Watch Service for this query.
+     * @param readTime - The last readTime received from the Watch Service for
+     * this query.
      *
      * This is the same value as TargetChange.read_time in the protos.
      */
     public readTime: DbTimestamp,
     /**
-     * An opaque, server-assigned token that allows watching a query to be
-     * resumed after disconnecting without retransmitting all the data
-     * that matches the query. The resume token essentially identifies a
-     * point in time from which the server should resume sending results.
+     * @param resumeToken - An opaque, server-assigned token that allows
+     * watching a query to be resumed after disconnecting without retransmitting
+     * all the data that matches the query. The resume token essentially
+     * identifies a point in time from which the server should resume sending
+     * results.
      *
      * This is related to the snapshotVersion in that the resumeToken
      * effectively also encodes that value, but the resumeToken is opaque
@@ -313,8 +371,9 @@ export class DbTarget {
      */
     public resumeToken: string,
     /**
-     * A sequence number representing the last time this query was
-     * listened to, used for garbage collection purposes.
+     * @param lastListenSequenceNumber - A sequence number representing the
+     * last time this query was listened to, used for garbage collection
+     * purposes.
      *
      * Conventionally this would be a timestamp value, but device-local
      * clocks are unreliable and they must be able to create new listens
@@ -328,7 +387,7 @@ export class DbTarget {
      */
     public lastListenSequenceNumber: number,
     /**
-     * The query for this target.
+     * @param query - The query for this target.
      *
      * Because canonical ids are not unique we must store the actual query. We
      * use the proto to have an object we can persist without having to
@@ -353,8 +412,8 @@ export class DbTargetDocument {
   /** Name of the IndexedDb object store.  */
   static store = 'targetDocuments';
 
-  /** Keys are automatically assigned via the targetId, snapshotVersion, and path properties. */
-  static keyPath = ['targetId', 'snapshotVersion', 'path'];
+  /** Keys are automatically assigned via the targetId, path properties. */
+  static keyPath = ['targetId', 'path'];
 
   /** The index name for the reverse index. */
   static documentTargetsIndex = 'documentTargetsIndex';
@@ -364,12 +423,11 @@ export class DbTargetDocument {
 
   constructor(
     /**
-     * The targetId identifying a target.
+     * @param targetId - The targetId identifying a target.
      */
     public targetId: TargetId,
-    public snapshotVersion: number,
     /**
-     * The path to the document, as encoded in the key.
+     * @param path - The path to the document, as encoded in the key.
      */
     public path: EncodedResourcePath
   ) {}
@@ -396,55 +454,141 @@ export class DbTargetGlobal {
 
   constructor(
     /**
-     * The highest numbered target id across all targets.
+     * @param highestTargetId - The highest numbered target id across all
+     * targets.
      *
      * See DbTarget.targetId.
      */
     public highestTargetId: TargetId,
     /**
-     * The highest numbered lastListenSequenceNumber across all targets.
+     * @param highestListenSequenceNumber - The highest numbered
+     * lastListenSequenceNumber across all targets.
      *
      * See DbTarget.lastListenSequenceNumber.
      */
     public highestListenSequenceNumber: number,
     /**
-     * A global snapshot version representing the last consistent snapshot we
-     * received from the backend. This is monotonically increasing and any
-     * snapshots received from the backend prior to this version (e.g. for
-     * targets resumed with a resumeToken) should be suppressed (buffered)
-     * until the backend has caught up to this snapshot version again. This
-     * prevents our cache from ever going backwards in time.
+     * @param lastRemoteSnapshotVersion - A global snapshot version representing
+     * the last consistent snapshot we received from the backend. This is
+     * monotonically increasing and any snapshots received from the backend
+     * prior to this version (e.g. for targets resumed with a resumeToken)
+     * should be suppressed (buffered) until the backend has caught up to this
+     * snapshot version again. This prevents our cache from ever going backwards
+     * in time.
      */
     public lastRemoteSnapshotVersion: DbTimestamp
   ) {}
 }
 
-export type DbInstanceKey = [string, string];
+function createQueryCache(db: IDBDatabase): void {
+  const targetDocumentsStore = db.createObjectStore(DbTargetDocument.store, {
+    keyPath: DbTargetDocument.keyPath as KeyPath
+  });
+  targetDocumentsStore.createIndex(
+    DbTargetDocument.documentTargetsIndex,
+    DbTargetDocument.documentTargetsKeyPath,
+    { unique: true }
+  );
+
+  const targetStore = db.createObjectStore(DbTarget.store, {
+    keyPath: DbTarget.keyPath
+  });
+
+  // NOTE: This is unique only because the TargetId is the suffix.
+  targetStore.createIndex(
+    DbTarget.queryTargetsIndexName,
+    DbTarget.queryTargetsKeyPath,
+    { unique: true }
+  );
+  db.createObjectStore(DbTargetGlobal.store);
+}
 
-export class DbInstance {
-  static store = 'instances';
+/**
+ * An object representing the changes at a particular snapshot version for the
+ * given target. This is used to facilitate storing query changelogs in the
+ * targetChanges object store.
+ *
+ * PORTING NOTE: This is used for change propagation during multi-tab syncing
+ * and not needed on iOS and Android.
+ */
+export class DbTargetChange {
+  /** Name of the IndexedDb object store.  */
+  static store = 'targetChanges';
 
-  static keyPath = ['userId', 'instanceId'];
+  /** Keys are automatically assigned via the targetId and snapshotVersion. */
+  static keyPath = ['targetId', 'snapshotVersion'];
 
   constructor(
-    public userId: string,
-    public instanceId: string,
-    public updateTimeMs: number
+    /**
+     * @param targetId - The targetId identifying a target.
+     */
+    public targetId: TargetId,
+    /**
+     * @param snapshotVersion - The snapshot version for this change.
+     */
+    public snapshotVersion: DbTimestamp,
+    /**
+     * @param changes - The keys of the changed documents in this snapshot.
+     */
+    public changes: {
+      added?: EncodedResourcePath[];
+      modified?: EncodedResourcePath[];
+      removed?: EncodedResourcePath[];
+    }
   ) {}
 }
 
+function createTargetChangeStore(db: IDBDatabase): void {
+  db.createObjectStore(DbTargetChange.store, {
+    keyPath: DbTargetChange.keyPath as KeyPath
+  });
+}
+
 /**
- * The list of all IndexedDB stored used by the SDK. This is used when creating
- * transactions so that access across all stores is done atomically.
+ * A record of the metadata state of each instance.
+ *
+ * PORTING NOTE: This is used for primary-tab selection to support multi-tab
+ * persistence and does not need to be ported to iOS or Android.
  */
-export const ALL_STORES = [
+export class DbInstanceMetadata {
+  /** Name of the IndexedDb object store. */
+  static store = 'instanceMetadata';
+
+  /** Keys are automatically assigned via the userId and instanceKey properties. */
+  static keyPath = ['userId', 'instanceKey'];
+
+  constructor(
+    /** userId - The normalized user ID to which this batch belongs.*/
+    public userId: string,
+    /** instanceKey - The auto-generated instance key assigned at client startup. */
+    public instanceKey: string,
+    /** updateTimeMs - The last time this state was updated. */
+    public updateTimeMs: DbTimestamp
+  ) {}
+}
+
+function createInstanceMetadataStore(db: IDBDatabase): void {
+  db.createObjectStore(DbInstanceMetadata.store, {
+    keyPath: DbInstanceMetadata.keyPath as KeyPath
+  });
+}
+
+// Exported for testing.
+export const V1_STORES = [
+  DbDocumentMutation.store,
   DbMutationQueue.store,
   DbMutationBatch.store,
-  DbDocumentMutation.store,
-  DbRemoteDocument.store,
-  DbTarget.store,
   DbOwner.store,
-  DbTargetGlobal.store,
+  DbRemoteDocument.store,
   DbTargetDocument.store,
-  DbInstance.store
+  DbTargetGlobal.store,
+  DbTarget.store
 ];
+
+const SCHEMA_V2_STORES = [DbInstanceMetadata.store, DbTargetChange.store];
+
+/**
+ * The list of all IndexedDB stored used by the SDK. This is used when creating
+ * transactions so that access across all stores is done atomically.
+ */
+export const ALL_STORES = [...V1_STORES, ...SCHEMA_V2_STORES];
diff --git a/packages/firestore/src/local/simple_db.ts b/packages/firestore/src/local/simple_db.ts
index c7f7ff87d98..8adbcad37d5 100644
--- a/packages/firestore/src/local/simple_db.ts
+++ b/packages/firestore/src/local/simple_db.ts
@@ -37,8 +37,8 @@ export class SimpleDb {
     version: number,
     runUpgrade: (
       db: IDBDatabase,
-      oldVersion: number,
-      newVersion: number
+      fromVersion: number,
+      toVersion: number
     ) => void
   ): Promise<SimpleDb> {
     assert(
diff --git a/packages/firestore/test/unit/local/schema_migration.test.ts b/packages/firestore/test/unit/local/schema_migration.test.ts
new file mode 100644
index 00000000000..8b5d1671a0b
--- /dev/null
+++ b/packages/firestore/test/unit/local/schema_migration.test.ts
@@ -0,0 +1,107 @@
+/**
+ * Copyright 2018 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { expect } from 'chai';
+import { IndexedDbMutationQueue } from '../../../src/local/indexeddb_mutation_queue';
+import { IndexedDbPersistence } from '../../../src/local/indexeddb_persistence';
+import {
+  ALL_STORES,
+  createOrUpgradeDb,
+  V1_STORES
+} from '../../../src/local/indexeddb_schema';
+import { Deferred } from '../../../src/util/promise';
+
+const INDEXEDDB_TEST_DATABASE = 'schemaTest';
+
+function deleteDb() {
+  const deferred = new Deferred<void>();
+
+  const request = window.indexedDB.deleteDatabase(INDEXEDDB_TEST_DATABASE);
+  request.onsuccess = (event: Event) => {
+    deferred.resolve();
+  };
+  request.onerror = (event: ErrorEvent) => {
+    deferred.reject((event.target as IDBOpenDBRequest).error);
+  };
+
+  return deferred;
+}
+
+function initDb(targetVersion) {
+  const deferred = new Deferred<IDBDatabase>();
+
+  const request = window.indexedDB.open(INDEXEDDB_TEST_DATABASE, targetVersion);
+  request.onsuccess = (event: Event) => {
+    const db = (event.target as IDBOpenDBRequest).result;
+    deferred.resolve(db);
+  };
+  request.onerror = (event: ErrorEvent) => {
+    deferred.reject((event.target as IDBOpenDBRequest).error);
+  };
+  request.onupgradeneeded = (event: IDBVersionChangeEvent) => {
+    const db = (event.target as IDBOpenDBRequest).result;
+    createOrUpgradeDb(db, event.oldVersion, targetVersion);
+  };
+
+  return deferred.promise;
+}
+
+function getAllObjectStores(db: IDBDatabase): String[] {
+  const objectStores: String[] = [];
+  for (let i = 0; i < db.objectStoreNames.length; ++i) {
+    objectStores.push(db.objectStoreNames.item(i));
+  }
+  objectStores.sort();
+  return objectStores;
+}
+
+// Sorting these arrays directly should not affect the functionality of the SDK.
+V1_STORES.sort();
+ALL_STORES.sort();
+
+describe('SchemaMigration', () => {
+  if (!IndexedDbPersistence.isAvailable()) {
+    console.warn('No IndexedDB. Skipping IndexedDbMutationQueue tests.');
+    return;
+  }
+
+  beforeEach(() => {
+    return deleteDb();
+  });
+
+  it('can install schema version 1', () => {
+    return initDb(1).then(db => {
+      expect(db.version).to.be.equal(1);
+      expect(getAllObjectStores(db)).to.deep.equal(V1_STORES);
+    });
+  });
+
+  it('can install schema version 2', () => {
+    return initDb(2).then(db => {
+      expect(db.version).to.be.equal(2);
+      expect(getAllObjectStores(db)).to.deep.equal(ALL_STORES);
+    });
+  });
+
+  it('can upgrade from schema version 1 to 2', () => {
+    return initDb(1)
+      .then(() => initDb(2))
+      .then(db => {
+        expect(db.version).to.be.equal(2);
+        expect(getAllObjectStores(db)).to.deep.equal(ALL_STORES);
+      });
+  });
+});

From fd5030170f404b65eb228cd7f822186ff6964c99 Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Tue, 6 Feb 2018 10:46:40 -0800
Subject: [PATCH 05/22] Lint cleanup

---
 packages/firestore/src/local/indexeddb_schema.ts | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/packages/firestore/src/local/indexeddb_schema.ts b/packages/firestore/src/local/indexeddb_schema.ts
index 89a0fb4f817..2b64538e9ed 100644
--- a/packages/firestore/src/local/indexeddb_schema.ts
+++ b/packages/firestore/src/local/indexeddb_schema.ts
@@ -42,7 +42,7 @@ export function createOrUpgradeDb(
     createTargetChangeStore(db);
   }
 
-  if (fromVersion == 0 && toVersion >= 1) {
+  if (fromVersion === 0 && toVersion >= 1) {
     createOwnerStore(db);
     createMutationQueue(db);
     createQueryCache(db);
@@ -129,7 +129,7 @@ export class DbMutationQueue {
      *
      * PORTING NOTE: iOS and Android clients keep this value in-memory.
      */
-    public highestPendingBatchId: number
+    public highestPendingBatchId?: number
   ) {}
 }
 
@@ -558,11 +558,14 @@ export class DbInstanceMetadata {
   static keyPath = ['userId', 'instanceKey'];
 
   constructor(
-    /** userId - The normalized user ID to which this batch belongs.*/
+    /** @param userId - The normalized user ID to which this batch belongs. */
     public userId: string,
-    /** instanceKey - The auto-generated instance key assigned at client startup. */
+    /**
+     * @param  instanceKey - The auto-generated instance key assigned at client
+     * startup.
+     */
     public instanceKey: string,
-    /** updateTimeMs - The last time this state was updated. */
+    /** @param  updateTimeMs - The last time this state was updated. */
     public updateTimeMs: DbTimestamp
   ) {}
 }

From be3b46358d087e309feb6c03e5cfbc5e90f71785 Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Tue, 6 Feb 2018 13:08:47 -0800
Subject: [PATCH 06/22] Removing unused import

---
 packages/firestore/test/unit/local/schema_migration.test.ts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/firestore/test/unit/local/schema_migration.test.ts b/packages/firestore/test/unit/local/schema_migration.test.ts
index 8b5d1671a0b..099ce80c2bc 100644
--- a/packages/firestore/test/unit/local/schema_migration.test.ts
+++ b/packages/firestore/test/unit/local/schema_migration.test.ts
@@ -15,7 +15,6 @@
  */
 
 import { expect } from 'chai';
-import { IndexedDbMutationQueue } from '../../../src/local/indexeddb_mutation_queue';
 import { IndexedDbPersistence } from '../../../src/local/indexeddb_persistence';
 import {
   ALL_STORES,

From de237c5fd601bed1dc2bcd11910340a320cf3a32 Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Tue, 6 Feb 2018 14:20:25 -0800
Subject: [PATCH 07/22] Removing user ID from instance row

---
 packages/firestore/src/local/indexeddb_schema.ts | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/packages/firestore/src/local/indexeddb_schema.ts b/packages/firestore/src/local/indexeddb_schema.ts
index 2b64538e9ed..61507b56965 100644
--- a/packages/firestore/src/local/indexeddb_schema.ts
+++ b/packages/firestore/src/local/indexeddb_schema.ts
@@ -558,15 +558,18 @@ export class DbInstanceMetadata {
   static keyPath = ['userId', 'instanceKey'];
 
   constructor(
-    /** @param userId - The normalized user ID to which this batch belongs. */
-    public userId: string,
     /**
      * @param  instanceKey - The auto-generated instance key assigned at client
      * startup.
      */
     public instanceKey: string,
     /** @param  updateTimeMs - The last time this state was updated. */
-    public updateTimeMs: DbTimestamp
+    public updateTimeMs: DbTimestamp,
+    /**
+     * @param isInForeground - Whether the instance is known to run in a
+     * foreground tab.
+     */
+    public isInForeground: boolean,
   ) {}
 }
 

From 53e56b5c08e87f5f345720230cd47433d59c78b9 Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Tue, 6 Feb 2018 14:21:22 -0800
Subject: [PATCH 08/22] [AUTOMATED]: Prettier Code Styling

---
 packages/firestore/src/local/indexeddb_schema.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/firestore/src/local/indexeddb_schema.ts b/packages/firestore/src/local/indexeddb_schema.ts
index 61507b56965..fe82b832b3b 100644
--- a/packages/firestore/src/local/indexeddb_schema.ts
+++ b/packages/firestore/src/local/indexeddb_schema.ts
@@ -569,7 +569,7 @@ export class DbInstanceMetadata {
      * @param isInForeground - Whether the instance is known to run in a
      * foreground tab.
      */
-    public isInForeground: boolean,
+    public isInForeground: boolean
   ) {}
 }
 

From 7b3bedb35ad7bea42a994d2d5367cc051857ddba Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Wed, 7 Feb 2018 11:28:50 -0800
Subject: [PATCH 09/22] Review comments

---
 .../src/local/indexeddb_persistence.ts        |   4 +-
 .../firestore/src/local/indexeddb_schema.ts   | 168 ++++++++----------
 packages/firestore/src/local/simple_db.ts     |   4 +-
 .../test/unit/local/schema_migration.test.ts  |  33 +---
 4 files changed, 89 insertions(+), 120 deletions(-)

diff --git a/packages/firestore/src/local/indexeddb_persistence.ts b/packages/firestore/src/local/indexeddb_persistence.ts
index b09548e5e2b..451bac4585e 100644
--- a/packages/firestore/src/local/indexeddb_persistence.ts
+++ b/packages/firestore/src/local/indexeddb_persistence.ts
@@ -30,7 +30,7 @@ import {
   createOrUpgradeDb,
   DbOwner,
   DbOwnerKey,
-  SCHEMA_VERSION
+  DEFAULT_SCHEMA_VERSION
 } from './indexeddb_schema';
 import { LocalSerializer } from './local_serializer';
 import { MutationQueue } from './mutation_queue';
@@ -132,7 +132,7 @@ export class IndexedDbPersistence implements Persistence {
     assert(!this.started, 'IndexedDbPersistence double-started!');
     this.started = true;
 
-    return SimpleDb.openOrCreate(this.dbName, SCHEMA_VERSION, createOrUpgradeDb)
+    return SimpleDb.openOrCreate(this.dbName, DEFAULT_SCHEMA_VERSION, createOrUpgradeDb)
       .then(db => {
         this.simpleDb = db;
       })
diff --git a/packages/firestore/src/local/indexeddb_schema.ts b/packages/firestore/src/local/indexeddb_schema.ts
index fe82b832b3b..655c90febda 100644
--- a/packages/firestore/src/local/indexeddb_schema.ts
+++ b/packages/firestore/src/local/indexeddb_schema.ts
@@ -21,33 +21,45 @@ import { ResourcePath } from '../model/path';
 import { assert } from '../util/assert';
 
 import { encode, EncodedResourcePath } from './encoded_resource_path';
+import {IndexedDbMutationQueue} from './indexeddb_mutation_queue';
+import {SimpleDb} from './simple_db';
 
-export const SCHEMA_VERSION = 2;
+/**
+ * Schema version containing the Mutation Queue, the Query and the Remote
+ * Document Cache.
+ */
+export const DEFAULT_SCHEMA_VERSION = 1;
 
 /**
- * Performs database creation and schema migrations up to schema version 2.
+ * Performs database creation and schema upgrades.
+ *
+ * Note that in production, this method is only ever used to upgrade the schema
+ * to DEFAULT_SCHEMA_VERSION. Different versions are only used for testing and
+ * local feature development.
  */
 export function createOrUpgradeDb(
   db: IDBDatabase,
   fromVersion: number,
   toVersion: number
 ): void {
+  // This function currently supports migrating to schema version 1 (Mutation
+  // Queue, Query and Remote Document Cache) and schema version 2 (Multi-Tab).
   assert(
     fromVersion < toVersion && fromVersion >= 0 && toVersion <= 2,
     'Unexpected schema upgrade from v${fromVersion} to v{toVersion}.'
   );
 
-  if (toVersion === 2) {
-    createInstanceMetadataStore(db);
-    createTargetChangeStore(db);
-  }
-
-  if (fromVersion === 0 && toVersion >= 1) {
+  if (fromVersion < 1 && toVersion >= 1) {
     createOwnerStore(db);
     createMutationQueue(db);
     createQueryCache(db);
     createRemoteDocumentCache(db);
   }
+
+  if (fromVersion < 2 && toVersion >= 2) {
+    createClientMetadataStore(db);
+    createTargetChangeStore(db);
+  }
 }
 
 // TODO(mikelehen): Get rid of "as any" if/when TypeScript fixes their types.
@@ -101,19 +113,18 @@ export class DbMutationQueue {
 
   constructor(
     /**
-     * @param userId - The normalized user ID to which this queue belongs.
+     * The normalized user ID to which this queue belongs.
      */
     public userId: string,
     /**
-     * @param lastAcknowledgedBatchId - An identifier for the highest numbered
-     * batch that has been acknowledged by the server. All MutationBatches in
-     * this queue with batchIds less than or equal to this value are considered
-     * to have been acknowledged by the server.
+     * An identifier for the highest numbered batch that has been acknowledged
+     * by the server. All MutationBatches in this queue with batchIds less
+     * than or equal to this value are considered to have been acknowledged by
+     * the server.
      */
     public lastAcknowledgedBatchId: number,
     /**
-     * @param lastStreamToken - A stream token that was previously sent by the
-     * server.
+     * A stream token that was previously sent by the server.
      *
      * See StreamingWriteRequest in datastore.proto for more details about
      * usage.
@@ -122,14 +133,6 @@ export class DbMutationQueue {
      * only a single stream token is retained.
      */
     public lastStreamToken: string,
-    /**
-     * @param highestPendingBatchId - An identifier for the highest numbered
-     * batch in the mutation queue. This allows for efficient insert of new
-     * batches without relying on in-memory state.
-     *
-     * PORTING NOTE: iOS and Android clients keep this value in-memory.
-     */
-    public highestPendingBatchId?: number
   ) {}
 }
 
@@ -152,22 +155,21 @@ export class DbMutationBatch {
 
   constructor(
     /**
-     * @userId userId - The normalized user ID to which this batch belongs.
+     * The normalized user ID to which this batch belongs.
      */
     public userId: string,
     /**
-     * @batchId batchId - An identifier for this batch, allocated by the
-     * mutation queue in a monotonically increasing manner.
+     * An identifier for this batch, allocated by the mutation queue in a
+     * monotonically increasing manner.
      */
     public batchId: BatchId,
     /**
-     * @param localWriteTimeMs - The local write time of the batch, stored as
-     * milliseconds since the epoch.
+     * The local write time of the batch, stored as milliseconds since the
+     * epoch.
      */
     public localWriteTimeMs: number,
     /**
-     * @param mutations - A list of mutations to apply. All mutations will be
-     * applied atomically.
+     * A list of mutations to apply. All mutations will be applied atomically.
      *
      * Mutations are serialized via JsonProtoSerializer.toMutation().
      */
@@ -191,8 +193,6 @@ function createMutationQueue(db: IDBDatabase): void {
     keyPath: DbMutationBatch.keyPath as KeyPath
   });
 
-  // NOTE: keys for these stores are specified explicitly rather than using a
-  // keyPath.
   db.createObjectStore(DbDocumentMutation.store);
 }
 
@@ -279,13 +279,13 @@ export class DbRemoteDocument {
 
   constructor(
     /**
-     * @param noDocument - Set to an instance of a DbNoDocument if it is known
-     * that no document exists.
+     * Set to an instance of a DbNoDocument if it is known that no document
+     * exists.
      */
     public noDocument: DbNoDocument | null,
     /**
-     * @param document - Set to an instance of a Document if there's a cached
-     * version of the document.
+     * Set to an instance of a Document if there's a cached version of the
+     * document.
      */
     public document: api.Document | null
   ) {}
@@ -330,8 +330,7 @@ export class DbTarget {
 
   constructor(
     /**
-     * @param targetId - An auto-generated sequential numeric identifier for the
-     * query.
+     * An auto-generated sequential numeric identifier for the query.
      *
      * Queries are stored using their canonicalId as the key, but these
      * canonicalIds can be quite long so we additionally assign a unique
@@ -340,23 +339,20 @@ export class DbTarget {
      */
     public targetId: TargetId,
     /**
-     * @param canonicalId - The canonical string representing this query. This
-     * is not unique.
+     * The canonical string representing this query. This is not unique.
      */
     public canonicalId: string,
     /**
-     * @param readTime - The last readTime received from the Watch Service for
-     * this query.
+     * The last readTime received from the Watch Service for this query.
      *
      * This is the same value as TargetChange.read_time in the protos.
      */
     public readTime: DbTimestamp,
     /**
-     * @param resumeToken - An opaque, server-assigned token that allows
-     * watching a query to be resumed after disconnecting without retransmitting
-     * all the data that matches the query. The resume token essentially
-     * identifies a point in time from which the server should resume sending
-     * results.
+     * An opaque, server-assigned token that allows watching a query to be
+     * resumed after disconnecting without retransmitting all the data
+     * that matches the query. The resume token essentially identifies a
+     * point in time from which the server should resume sending results.
      *
      * This is related to the snapshotVersion in that the resumeToken
      * effectively also encodes that value, but the resumeToken is opaque
@@ -371,9 +367,8 @@ export class DbTarget {
      */
     public resumeToken: string,
     /**
-     * @param lastListenSequenceNumber - A sequence number representing the
-     * last time this query was listened to, used for garbage collection
-     * purposes.
+     * A sequence number representing the last time this query was
+     * listened to, used for garbage collection purposes.
      *
      * Conventionally this would be a timestamp value, but device-local
      * clocks are unreliable and they must be able to create new listens
@@ -387,7 +382,7 @@ export class DbTarget {
      */
     public lastListenSequenceNumber: number,
     /**
-     * @param query - The query for this target.
+     * The query for this target.
      *
      * Because canonical ids are not unique we must store the actual query. We
      * use the proto to have an object we can persist without having to
@@ -423,11 +418,11 @@ export class DbTargetDocument {
 
   constructor(
     /**
-     * @param targetId - The targetId identifying a target.
+     * The targetId identifying a target.
      */
     public targetId: TargetId,
     /**
-     * @param path - The path to the document, as encoded in the key.
+     * The path to the document, as encoded in the key.
      */
     public path: EncodedResourcePath
   ) {}
@@ -454,27 +449,24 @@ export class DbTargetGlobal {
 
   constructor(
     /**
-     * @param highestTargetId - The highest numbered target id across all
-     * targets.
+     * The highest numbered target id across all targets.
      *
      * See DbTarget.targetId.
      */
     public highestTargetId: TargetId,
     /**
-     * @param highestListenSequenceNumber - The highest numbered
-     * lastListenSequenceNumber across all targets.
+     * The highest numbered lastListenSequenceNumber across all targets.
      *
      * See DbTarget.lastListenSequenceNumber.
      */
     public highestListenSequenceNumber: number,
     /**
-     * @param lastRemoteSnapshotVersion - A global snapshot version representing
-     * the last consistent snapshot we received from the backend. This is
-     * monotonically increasing and any snapshots received from the backend
-     * prior to this version (e.g. for targets resumed with a resumeToken)
-     * should be suppressed (buffered) until the backend has caught up to this
-     * snapshot version again. This prevents our cache from ever going backwards
-     * in time.
+     * A global snapshot version representing the last consistent snapshot we
+     * received from the backend. This is monotonically increasing and any
+     * snapshots received from the backend prior to this version (e.g. for
+     * targets resumed with a resumeToken) should be suppressed (buffered)
+     * until the backend has caught up to this snapshot version again. This
+     * prevents our cache from ever going backwards in time.
      */
     public lastRemoteSnapshotVersion: DbTimestamp
   ) {}
@@ -520,15 +512,15 @@ export class DbTargetChange {
 
   constructor(
     /**
-     * @param targetId - The targetId identifying a target.
+     * The targetId identifying a target.
      */
     public targetId: TargetId,
     /**
-     * @param snapshotVersion - The snapshot version for this change.
+     * The snapshot version for this change.
      */
     public snapshotVersion: DbTimestamp,
     /**
-     * @param changes - The keys of the changed documents in this snapshot.
+     * The keys of the changed documents in this snapshot.
      */
     public changes: {
       added?: EncodedResourcePath[];
@@ -545,37 +537,31 @@ function createTargetChangeStore(db: IDBDatabase): void {
 }
 
 /**
- * A record of the metadata state of each instance.
+ * A record of the metadata state of each client.
  *
- * PORTING NOTE: This is used for primary-tab selection to support multi-tab
- * persistence and does not need to be ported to iOS or Android.
+ * PORTING NOTE: This is used to synchronize multi-tab state and does not need
+ * to be ported to iOS or Android.
  */
-export class DbInstanceMetadata {
+export class DbClientMetadata {
   /** Name of the IndexedDb object store. */
-  static store = 'instanceMetadata';
+  static store = 'clientMetadata';
 
-  /** Keys are automatically assigned via the userId and instanceKey properties. */
-  static keyPath = ['userId', 'instanceKey'];
+  /** Keys are automatically assigned via the clientKey properties. */
+  static keyPath = ['clientKey'];
 
   constructor(
-    /**
-     * @param  instanceKey - The auto-generated instance key assigned at client
-     * startup.
-     */
-    public instanceKey: string,
-    /** @param  updateTimeMs - The last time this state was updated. */
+    /** The auto-generated client key assigned at client startup. */
+    public clientKey: string,
+    /** The last time this state was updated. */
     public updateTimeMs: DbTimestamp,
-    /**
-     * @param isInForeground - Whether the instance is known to run in a
-     * foreground tab.
-     */
-    public isInForeground: boolean
+    /** Whether this client is running in a foreground tab. */
+    public inForeground: boolean
   ) {}
 }
 
-function createInstanceMetadataStore(db: IDBDatabase): void {
-  db.createObjectStore(DbInstanceMetadata.store, {
-    keyPath: DbInstanceMetadata.keyPath as KeyPath
+function createClientMetadataStore(db: IDBDatabase): void {
+  db.createObjectStore(DbClientMetadata.store, {
+    keyPath: DbClientMetadata.keyPath as KeyPath
   });
 }
 
@@ -591,10 +577,10 @@ export const V1_STORES = [
   DbTarget.store
 ];
 
-const SCHEMA_V2_STORES = [DbInstanceMetadata.store, DbTargetChange.store];
+const V2_STORES = [DbClientMetadata.store, DbTargetChange.store];
 
 /**
- * The list of all IndexedDB stored used by the SDK. This is used when creating
+ * The list of all IndexedDB stores used by the SDK. This is used when creating
  * transactions so that access across all stores is done atomically.
  */
-export const ALL_STORES = [...V1_STORES, ...SCHEMA_V2_STORES];
+export const ALL_STORES = [...V1_STORES, ...V2_STORES];
diff --git a/packages/firestore/src/local/simple_db.ts b/packages/firestore/src/local/simple_db.ts
index 8adbcad37d5..d6f7e432681 100644
--- a/packages/firestore/src/local/simple_db.ts
+++ b/packages/firestore/src/local/simple_db.ts
@@ -19,7 +19,7 @@ import { debug } from '../util/log';
 import { AnyDuringMigration } from '../util/misc';
 
 import { PersistencePromise } from './persistence_promise';
-import { SCHEMA_VERSION } from './indexeddb_schema';
+import { DEFAULT_SCHEMA_VERSION } from './indexeddb_schema';
 
 const LOG_TAG = 'SimpleDb';
 
@@ -75,7 +75,7 @@ export class SimpleDb {
         // cheating and just passing the raw IndexedDB in, since
         // createObjectStore(), etc. are synchronous.
         const db = (event.target as IDBOpenDBRequest).result;
-        runUpgrade(db, event.oldVersion, SCHEMA_VERSION);
+        runUpgrade(db, event.oldVersion, DEFAULT_SCHEMA_VERSION);
       };
     }).toPromise();
   }
diff --git a/packages/firestore/test/unit/local/schema_migration.test.ts b/packages/firestore/test/unit/local/schema_migration.test.ts
index 099ce80c2bc..3af4f5d4a82 100644
--- a/packages/firestore/test/unit/local/schema_migration.test.ts
+++ b/packages/firestore/test/unit/local/schema_migration.test.ts
@@ -22,24 +22,11 @@ import {
   V1_STORES
 } from '../../../src/local/indexeddb_schema';
 import { Deferred } from '../../../src/util/promise';
+import {SimpleDb} from '../../../src/local/simple_db';
 
 const INDEXEDDB_TEST_DATABASE = 'schemaTest';
 
-function deleteDb() {
-  const deferred = new Deferred<void>();
-
-  const request = window.indexedDB.deleteDatabase(INDEXEDDB_TEST_DATABASE);
-  request.onsuccess = (event: Event) => {
-    deferred.resolve();
-  };
-  request.onerror = (event: ErrorEvent) => {
-    deferred.reject((event.target as IDBOpenDBRequest).error);
-  };
-
-  return deferred;
-}
-
-function initDb(targetVersion) {
+function initDb(targetVersion) : Promise<IDBDatabase> {
   const deferred = new Deferred<IDBDatabase>();
 
   const request = window.indexedDB.open(INDEXEDDB_TEST_DATABASE, targetVersion);
@@ -67,31 +54,27 @@ function getAllObjectStores(db: IDBDatabase): String[] {
   return objectStores;
 }
 
-// Sorting these arrays directly should not affect the functionality of the SDK.
-V1_STORES.sort();
-ALL_STORES.sort();
-
-describe('SchemaMigration', () => {
+describe('IndexedDbSchema: createOrUpgradeDb', () => {
   if (!IndexedDbPersistence.isAvailable()) {
-    console.warn('No IndexedDB. Skipping IndexedDbMutationQueue tests.');
+    console.warn('No IndexedDB. Skipping createOrUpgradeDb() tests.');
     return;
   }
 
   beforeEach(() => {
-    return deleteDb();
+    return SimpleDb.delete(INDEXEDDB_TEST_DATABASE);
   });
 
   it('can install schema version 1', () => {
     return initDb(1).then(db => {
       expect(db.version).to.be.equal(1);
-      expect(getAllObjectStores(db)).to.deep.equal(V1_STORES);
+      expect(getAllObjectStores(db)).to.have.members(V1_STORES);
     });
   });
 
   it('can install schema version 2', () => {
     return initDb(2).then(db => {
       expect(db.version).to.be.equal(2);
-      expect(getAllObjectStores(db)).to.deep.equal(ALL_STORES);
+      expect(getAllObjectStores(db)).to.have.members(ALL_STORES);
     });
   });
 
@@ -100,7 +83,7 @@ describe('SchemaMigration', () => {
       .then(() => initDb(2))
       .then(db => {
         expect(db.version).to.be.equal(2);
-        expect(getAllObjectStores(db)).to.deep.equal(ALL_STORES);
+        expect(getAllObjectStores(db)).to.have.members(ALL_STORES);
       });
   });
 });

From c176eff2aa7d17ac94c5d98c144de8695f56cd4b Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Wed, 7 Feb 2018 11:29:40 -0800
Subject: [PATCH 10/22] Lint fixes

---
 packages/firestore/src/local/indexeddb_schema.ts | 2 --
 1 file changed, 2 deletions(-)

diff --git a/packages/firestore/src/local/indexeddb_schema.ts b/packages/firestore/src/local/indexeddb_schema.ts
index 655c90febda..5536c008e60 100644
--- a/packages/firestore/src/local/indexeddb_schema.ts
+++ b/packages/firestore/src/local/indexeddb_schema.ts
@@ -21,8 +21,6 @@ import { ResourcePath } from '../model/path';
 import { assert } from '../util/assert';
 
 import { encode, EncodedResourcePath } from './encoded_resource_path';
-import {IndexedDbMutationQueue} from './indexeddb_mutation_queue';
-import {SimpleDb} from './simple_db';
 
 /**
  * Schema version containing the Mutation Queue, the Query and the Remote

From 9154aad4d605ef99680702c0e06b11e4bc19f702 Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Wed, 7 Feb 2018 11:32:51 -0800
Subject: [PATCH 11/22] Review

---
 packages/firestore/src/local/indexeddb_schema.ts | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/packages/firestore/src/local/indexeddb_schema.ts b/packages/firestore/src/local/indexeddb_schema.ts
index 5536c008e60..93ed7fa7d7f 100644
--- a/packages/firestore/src/local/indexeddb_schema.ts
+++ b/packages/firestore/src/local/indexeddb_schema.ts
@@ -23,8 +23,8 @@ import { assert } from '../util/assert';
 import { encode, EncodedResourcePath } from './encoded_resource_path';
 
 /**
- * Schema version containing the Mutation Queue, the Query and the Remote
- * Document Cache.
+ * Default Schema Version for the Web client (containing the Mutation Queue, the
+ * Query and the Remote Document Cache).
  */
 export const DEFAULT_SCHEMA_VERSION = 1;
 
@@ -130,7 +130,7 @@ export class DbMutationQueue {
      * After sending this token, earlier tokens may not be used anymore so
      * only a single stream token is retained.
      */
-    public lastStreamToken: string,
+    public lastStreamToken: string
   ) {}
 }
 
@@ -565,14 +565,14 @@ function createClientMetadataStore(db: IDBDatabase): void {
 
 // Exported for testing.
 export const V1_STORES = [
-  DbDocumentMutation.store,
   DbMutationQueue.store,
   DbMutationBatch.store,
-  DbOwner.store,
+  DbDocumentMutation.store,
   DbRemoteDocument.store,
-  DbTargetDocument.store,
+  DbTarget.store,
+  DbOwner.store,
   DbTargetGlobal.store,
-  DbTarget.store
+  DbTargetDocument.store
 ];
 
 const V2_STORES = [DbClientMetadata.store, DbTargetChange.store];

From 6b072ff3381b0cd315971c0aa7ebfb7dea0c37a0 Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Wed, 7 Feb 2018 11:33:15 -0800
Subject: [PATCH 12/22] [AUTOMATED]: Prettier Code Styling

---
 packages/firestore/src/local/indexeddb_persistence.ts       | 6 +++++-
 packages/firestore/test/unit/local/schema_migration.test.ts | 4 ++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/packages/firestore/src/local/indexeddb_persistence.ts b/packages/firestore/src/local/indexeddb_persistence.ts
index 451bac4585e..a56eaba98e4 100644
--- a/packages/firestore/src/local/indexeddb_persistence.ts
+++ b/packages/firestore/src/local/indexeddb_persistence.ts
@@ -132,7 +132,11 @@ export class IndexedDbPersistence implements Persistence {
     assert(!this.started, 'IndexedDbPersistence double-started!');
     this.started = true;
 
-    return SimpleDb.openOrCreate(this.dbName, DEFAULT_SCHEMA_VERSION, createOrUpgradeDb)
+    return SimpleDb.openOrCreate(
+      this.dbName,
+      DEFAULT_SCHEMA_VERSION,
+      createOrUpgradeDb
+    )
       .then(db => {
         this.simpleDb = db;
       })
diff --git a/packages/firestore/test/unit/local/schema_migration.test.ts b/packages/firestore/test/unit/local/schema_migration.test.ts
index 3af4f5d4a82..c0cc75373b9 100644
--- a/packages/firestore/test/unit/local/schema_migration.test.ts
+++ b/packages/firestore/test/unit/local/schema_migration.test.ts
@@ -22,11 +22,11 @@ import {
   V1_STORES
 } from '../../../src/local/indexeddb_schema';
 import { Deferred } from '../../../src/util/promise';
-import {SimpleDb} from '../../../src/local/simple_db';
+import { SimpleDb } from '../../../src/local/simple_db';
 
 const INDEXEDDB_TEST_DATABASE = 'schemaTest';
 
-function initDb(targetVersion) : Promise<IDBDatabase> {
+function initDb(targetVersion): Promise<IDBDatabase> {
   const deferred = new Deferred<IDBDatabase>();
 
   const request = window.indexedDB.open(INDEXEDDB_TEST_DATABASE, targetVersion);

From 662365ff8c3b61a6cf74398270518406a584123f Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Wed, 7 Feb 2018 11:53:09 -0800
Subject: [PATCH 13/22] Fixing the tests

---
 .../firestore/src/local/indexeddb_persistence.ts   |  4 ++--
 packages/firestore/src/local/indexeddb_schema.ts   | 14 ++++++++++----
 .../test/unit/local/schema_migration.test.ts       |  6 +++---
 3 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/packages/firestore/src/local/indexeddb_persistence.ts b/packages/firestore/src/local/indexeddb_persistence.ts
index a56eaba98e4..d6e17708a93 100644
--- a/packages/firestore/src/local/indexeddb_persistence.ts
+++ b/packages/firestore/src/local/indexeddb_persistence.ts
@@ -26,7 +26,7 @@ import { IndexedDbMutationQueue } from './indexeddb_mutation_queue';
 import { IndexedDbQueryCache } from './indexeddb_query_cache';
 import { IndexedDbRemoteDocumentCache } from './indexeddb_remote_document_cache';
 import {
-  ALL_STORES,
+  DEFAULT_STORES,
   createOrUpgradeDb,
   DbOwner,
   DbOwnerKey,
@@ -181,7 +181,7 @@ export class IndexedDbPersistence implements Persistence {
 
     // Do all transactions as readwrite against all object stores, since we
     // are the only reader/writer.
-    return this.simpleDb.runTransaction('readwrite', ALL_STORES, txn => {
+    return this.simpleDb.runTransaction('readwrite', DEFAULT_STORES, txn => {
       // Verify that we still have the owner lease as part of every transaction.
       return this.ensureOwnerLease(txn).next(() => operation(txn));
     });
diff --git a/packages/firestore/src/local/indexeddb_schema.ts b/packages/firestore/src/local/indexeddb_schema.ts
index 93ed7fa7d7f..1cbafb87c22 100644
--- a/packages/firestore/src/local/indexeddb_schema.ts
+++ b/packages/firestore/src/local/indexeddb_schema.ts
@@ -563,8 +563,7 @@ function createClientMetadataStore(db: IDBDatabase): void {
   });
 }
 
-// Exported for testing.
-export const V1_STORES = [
+const V1_STORES = [
   DbMutationQueue.store,
   DbMutationBatch.store,
   DbDocumentMutation.store,
@@ -578,7 +577,14 @@ export const V1_STORES = [
 const V2_STORES = [DbClientMetadata.store, DbTargetChange.store];
 
 /**
- * The list of all IndexedDB stores used by the SDK. This is used when creating
- * transactions so that access across all stores is done atomically.
+ * The list of all default IndexedDB stores used throughout the SDK. This is
+ * used when creating transactions so that access across all stores is done
+ * atomically.
+ */
+export const DEFAULT_STORES = V1_STORES;
+
+/**
+ * The list of all IndexedDb stores. This is only available in multi-tab enabled
+ * clients with the schema version 2.
  */
 export const ALL_STORES = [...V1_STORES, ...V2_STORES];
diff --git a/packages/firestore/test/unit/local/schema_migration.test.ts b/packages/firestore/test/unit/local/schema_migration.test.ts
index c0cc75373b9..f3f0f461759 100644
--- a/packages/firestore/test/unit/local/schema_migration.test.ts
+++ b/packages/firestore/test/unit/local/schema_migration.test.ts
@@ -17,9 +17,9 @@
 import { expect } from 'chai';
 import { IndexedDbPersistence } from '../../../src/local/indexeddb_persistence';
 import {
-  ALL_STORES,
+  DEFAULT_STORES,
   createOrUpgradeDb,
-  V1_STORES
+  ALL_STORES
 } from '../../../src/local/indexeddb_schema';
 import { Deferred } from '../../../src/util/promise';
 import { SimpleDb } from '../../../src/local/simple_db';
@@ -67,7 +67,7 @@ describe('IndexedDbSchema: createOrUpgradeDb', () => {
   it('can install schema version 1', () => {
     return initDb(1).then(db => {
       expect(db.version).to.be.equal(1);
-      expect(getAllObjectStores(db)).to.have.members(V1_STORES);
+      expect(getAllObjectStores(db)).to.have.members(DEFAULT_STORES);
     });
   });
 

From dd213769e1f3834a48db6fbeca53be1003ac7194 Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Wed, 7 Feb 2018 17:51:11 -0800
Subject: [PATCH 14/22] Closing the Database in the Schema tests

---
 .../test/unit/local/schema_migration.test.ts         | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/packages/firestore/test/unit/local/schema_migration.test.ts b/packages/firestore/test/unit/local/schema_migration.test.ts
index f3f0f461759..9c6f9a0abb6 100644
--- a/packages/firestore/test/unit/local/schema_migration.test.ts
+++ b/packages/firestore/test/unit/local/schema_migration.test.ts
@@ -60,14 +60,13 @@ describe('IndexedDbSchema: createOrUpgradeDb', () => {
     return;
   }
 
-  beforeEach(() => {
-    return SimpleDb.delete(INDEXEDDB_TEST_DATABASE);
-  });
+  beforeEach(() => SimpleDb.delete(INDEXEDDB_TEST_DATABASE));
 
   it('can install schema version 1', () => {
     return initDb(1).then(db => {
       expect(db.version).to.be.equal(1);
       expect(getAllObjectStores(db)).to.have.members(DEFAULT_STORES);
+      db.close();
     });
   });
 
@@ -75,15 +74,20 @@ describe('IndexedDbSchema: createOrUpgradeDb', () => {
     return initDb(2).then(db => {
       expect(db.version).to.be.equal(2);
       expect(getAllObjectStores(db)).to.have.members(ALL_STORES);
+      db.close();
     });
   });
 
   it('can upgrade from schema version 1 to 2', () => {
     return initDb(1)
-      .then(() => initDb(2))
+      .then(db => {
+        db.close();
+        return initDb(2)
+      })
       .then(db => {
         expect(db.version).to.be.equal(2);
         expect(getAllObjectStores(db)).to.have.members(ALL_STORES);
+        db.close();
       });
   });
 });

From 5e54b3a7ca2e71cdfbb8bf581fa3303c95cea51d Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Wed, 7 Feb 2018 17:51:35 -0800
Subject: [PATCH 15/22] [AUTOMATED]: Prettier Code Styling

---
 packages/firestore/test/unit/local/schema_migration.test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/firestore/test/unit/local/schema_migration.test.ts b/packages/firestore/test/unit/local/schema_migration.test.ts
index 9c6f9a0abb6..56393f2634a 100644
--- a/packages/firestore/test/unit/local/schema_migration.test.ts
+++ b/packages/firestore/test/unit/local/schema_migration.test.ts
@@ -82,7 +82,7 @@ describe('IndexedDbSchema: createOrUpgradeDb', () => {
     return initDb(1)
       .then(db => {
         db.close();
-        return initDb(2)
+        return initDb(2);
       })
       .then(db => {
         expect(db.version).to.be.equal(2);

From cb81df80da2f4dc3b03f52b55e5f92f2214a7243 Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Wed, 7 Feb 2018 22:42:31 -0800
Subject: [PATCH 16/22] Changing test helper to close the DB

---
 .../test/unit/local/schema_migration.test.ts  | 50 ++++++++-----------
 1 file changed, 21 insertions(+), 29 deletions(-)

diff --git a/packages/firestore/test/unit/local/schema_migration.test.ts b/packages/firestore/test/unit/local/schema_migration.test.ts
index 56393f2634a..014d63fdf64 100644
--- a/packages/firestore/test/unit/local/schema_migration.test.ts
+++ b/packages/firestore/test/unit/local/schema_migration.test.ts
@@ -26,23 +26,23 @@ import { SimpleDb } from '../../../src/local/simple_db';
 
 const INDEXEDDB_TEST_DATABASE = 'schemaTest';
 
-function initDb(targetVersion): Promise<IDBDatabase> {
-  const deferred = new Deferred<IDBDatabase>();
-
-  const request = window.indexedDB.open(INDEXEDDB_TEST_DATABASE, targetVersion);
-  request.onsuccess = (event: Event) => {
-    const db = (event.target as IDBOpenDBRequest).result;
-    deferred.resolve(db);
-  };
-  request.onerror = (event: ErrorEvent) => {
-    deferred.reject((event.target as IDBOpenDBRequest).error);
-  };
-  request.onupgradeneeded = (event: IDBVersionChangeEvent) => {
-    const db = (event.target as IDBOpenDBRequest).result;
-    createOrUpgradeDb(db, event.oldVersion, targetVersion);
-  };
-
-  return deferred.promise;
+function withDb(schemaVersion, fn: (db: IDBDatabase) => void): Promise<void> {
+  return new Promise<IDBDatabase>((resolve, reject) => {
+    const request = window.indexedDB.open(INDEXEDDB_TEST_DATABASE, schemaVersion);
+    request.onupgradeneeded = (event: IDBVersionChangeEvent) => {
+      const db = (event.target as IDBOpenDBRequest).result;
+      createOrUpgradeDb(db, event.oldVersion, schemaVersion);
+    };
+    request.onsuccess = (event: Event) => {
+      resolve((event.target as IDBOpenDBRequest).result);
+    };
+    request.onerror = (event: ErrorEvent) => {
+      reject((event.target as IDBOpenDBRequest).error);
+    };
+  }).then(db => {
+    fn(db);
+    return db;
+  }).then(db => { db.close()});
 }
 
 function getAllObjectStores(db: IDBDatabase): String[] {
@@ -63,31 +63,23 @@ describe('IndexedDbSchema: createOrUpgradeDb', () => {
   beforeEach(() => SimpleDb.delete(INDEXEDDB_TEST_DATABASE));
 
   it('can install schema version 1', () => {
-    return initDb(1).then(db => {
+    return withDb(1, db => {
       expect(db.version).to.be.equal(1);
       expect(getAllObjectStores(db)).to.have.members(DEFAULT_STORES);
-      db.close();
     });
   });
 
   it('can install schema version 2', () => {
-    return initDb(2).then(db => {
+    return withDb(2,db => {
       expect(db.version).to.be.equal(2);
       expect(getAllObjectStores(db)).to.have.members(ALL_STORES);
-      db.close();
     });
   });
 
   it('can upgrade from schema version 1 to 2', () => {
-    return initDb(1)
-      .then(db => {
-        db.close();
-        return initDb(2);
-      })
-      .then(db => {
+    return withDb(1,() => {}).then(() => withDb(2, (db) => {
         expect(db.version).to.be.equal(2);
         expect(getAllObjectStores(db)).to.have.members(ALL_STORES);
-        db.close();
-      });
+      }));
   });
 });

From 79919709b6cecffcdde7806675bf4231fd1a56cb Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Wed, 7 Feb 2018 22:42:53 -0800
Subject: [PATCH 17/22] [AUTOMATED]: Prettier Code Styling

---
 .../test/unit/local/schema_migration.test.ts  | 25 +++++++++++++------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/packages/firestore/test/unit/local/schema_migration.test.ts b/packages/firestore/test/unit/local/schema_migration.test.ts
index 014d63fdf64..eebf315f474 100644
--- a/packages/firestore/test/unit/local/schema_migration.test.ts
+++ b/packages/firestore/test/unit/local/schema_migration.test.ts
@@ -28,7 +28,10 @@ const INDEXEDDB_TEST_DATABASE = 'schemaTest';
 
 function withDb(schemaVersion, fn: (db: IDBDatabase) => void): Promise<void> {
   return new Promise<IDBDatabase>((resolve, reject) => {
-    const request = window.indexedDB.open(INDEXEDDB_TEST_DATABASE, schemaVersion);
+    const request = window.indexedDB.open(
+      INDEXEDDB_TEST_DATABASE,
+      schemaVersion
+    );
     request.onupgradeneeded = (event: IDBVersionChangeEvent) => {
       const db = (event.target as IDBOpenDBRequest).result;
       createOrUpgradeDb(db, event.oldVersion, schemaVersion);
@@ -39,10 +42,14 @@ function withDb(schemaVersion, fn: (db: IDBDatabase) => void): Promise<void> {
     request.onerror = (event: ErrorEvent) => {
       reject((event.target as IDBOpenDBRequest).error);
     };
-  }).then(db => {
-    fn(db);
-    return db;
-  }).then(db => { db.close()});
+  })
+    .then(db => {
+      fn(db);
+      return db;
+    })
+    .then(db => {
+      db.close();
+    });
 }
 
 function getAllObjectStores(db: IDBDatabase): String[] {
@@ -70,16 +77,18 @@ describe('IndexedDbSchema: createOrUpgradeDb', () => {
   });
 
   it('can install schema version 2', () => {
-    return withDb(2,db => {
+    return withDb(2, db => {
       expect(db.version).to.be.equal(2);
       expect(getAllObjectStores(db)).to.have.members(ALL_STORES);
     });
   });
 
   it('can upgrade from schema version 1 to 2', () => {
-    return withDb(1,() => {}).then(() => withDb(2, (db) => {
+    return withDb(1, () => {}).then(() =>
+      withDb(2, db => {
         expect(db.version).to.be.equal(2);
         expect(getAllObjectStores(db)).to.have.members(ALL_STORES);
-      }));
+      })
+    );
   });
 });

From 2c6d6e16f32259a3694fad532d7f16211dfa3608 Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Thu, 8 Feb 2018 18:19:26 -0800
Subject: [PATCH 18/22] Making v2 the default version

---
 .../firestore/src/local/indexeddb_persistence.ts |  4 ++--
 packages/firestore/src/local/indexeddb_schema.ts | 16 +++++-----------
 packages/firestore/src/local/simple_db.ts        |  4 ++--
 3 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/packages/firestore/src/local/indexeddb_persistence.ts b/packages/firestore/src/local/indexeddb_persistence.ts
index d6e17708a93..0ede8f4159f 100644
--- a/packages/firestore/src/local/indexeddb_persistence.ts
+++ b/packages/firestore/src/local/indexeddb_persistence.ts
@@ -30,7 +30,7 @@ import {
   createOrUpgradeDb,
   DbOwner,
   DbOwnerKey,
-  DEFAULT_SCHEMA_VERSION
+  SCHEMA_VERSION
 } from './indexeddb_schema';
 import { LocalSerializer } from './local_serializer';
 import { MutationQueue } from './mutation_queue';
@@ -134,7 +134,7 @@ export class IndexedDbPersistence implements Persistence {
 
     return SimpleDb.openOrCreate(
       this.dbName,
-      DEFAULT_SCHEMA_VERSION,
+      SCHEMA_VERSION,
       createOrUpgradeDb
     )
       .then(db => {
diff --git a/packages/firestore/src/local/indexeddb_schema.ts b/packages/firestore/src/local/indexeddb_schema.ts
index 1cbafb87c22..eabc16a7a31 100644
--- a/packages/firestore/src/local/indexeddb_schema.ts
+++ b/packages/firestore/src/local/indexeddb_schema.ts
@@ -23,16 +23,16 @@ import { assert } from '../util/assert';
 import { encode, EncodedResourcePath } from './encoded_resource_path';
 
 /**
- * Default Schema Version for the Web client (containing the Mutation Queue, the
- * Query and the Remote Document Cache).
+ * Schema Version for the Web client (containing the Mutation Queue, the Query
+ * and the Remote Document Cache) and Multi-Tab Support.
  */
-export const DEFAULT_SCHEMA_VERSION = 1;
+export const SCHEMA_VERSION = 2;
 
 /**
  * Performs database creation and schema upgrades.
  *
  * Note that in production, this method is only ever used to upgrade the schema
- * to DEFAULT_SCHEMA_VERSION. Different versions are only used for testing and
+ * to SCHEMA_VERSION. Different versions are only used for testing and
  * local feature development.
  */
 export function createOrUpgradeDb(
@@ -581,10 +581,4 @@ const V2_STORES = [DbClientMetadata.store, DbTargetChange.store];
  * used when creating transactions so that access across all stores is done
  * atomically.
  */
-export const DEFAULT_STORES = V1_STORES;
-
-/**
- * The list of all IndexedDb stores. This is only available in multi-tab enabled
- * clients with the schema version 2.
- */
-export const ALL_STORES = [...V1_STORES, ...V2_STORES];
+export const DEFAULT_STORES = [...V1_STORES, ...V2_STORES];
diff --git a/packages/firestore/src/local/simple_db.ts b/packages/firestore/src/local/simple_db.ts
index d6f7e432681..8adbcad37d5 100644
--- a/packages/firestore/src/local/simple_db.ts
+++ b/packages/firestore/src/local/simple_db.ts
@@ -19,7 +19,7 @@ import { debug } from '../util/log';
 import { AnyDuringMigration } from '../util/misc';
 
 import { PersistencePromise } from './persistence_promise';
-import { DEFAULT_SCHEMA_VERSION } from './indexeddb_schema';
+import { SCHEMA_VERSION } from './indexeddb_schema';
 
 const LOG_TAG = 'SimpleDb';
 
@@ -75,7 +75,7 @@ export class SimpleDb {
         // cheating and just passing the raw IndexedDB in, since
         // createObjectStore(), etc. are synchronous.
         const db = (event.target as IDBOpenDBRequest).result;
-        runUpgrade(db, event.oldVersion, DEFAULT_SCHEMA_VERSION);
+        runUpgrade(db, event.oldVersion, SCHEMA_VERSION);
       };
     }).toPromise();
   }

From f16bb4fc5729da1f1104c9d2271eef2248920d4a Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Thu, 8 Feb 2018 18:19:48 -0800
Subject: [PATCH 19/22] [AUTOMATED]: Prettier Code Styling

---
 packages/firestore/src/local/indexeddb_persistence.ts | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/packages/firestore/src/local/indexeddb_persistence.ts b/packages/firestore/src/local/indexeddb_persistence.ts
index 0ede8f4159f..3dc3e287495 100644
--- a/packages/firestore/src/local/indexeddb_persistence.ts
+++ b/packages/firestore/src/local/indexeddb_persistence.ts
@@ -132,11 +132,7 @@ export class IndexedDbPersistence implements Persistence {
     assert(!this.started, 'IndexedDbPersistence double-started!');
     this.started = true;
 
-    return SimpleDb.openOrCreate(
-      this.dbName,
-      SCHEMA_VERSION,
-      createOrUpgradeDb
-    )
+    return SimpleDb.openOrCreate(this.dbName, SCHEMA_VERSION, createOrUpgradeDb)
       .then(db => {
         this.simpleDb = db;
       })

From 038c1599816821710679f26c7cdfebeefc3120f7 Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Thu, 8 Feb 2018 18:24:23 -0800
Subject: [PATCH 20/22] Addressing comment

---
 packages/firestore/src/local/indexeddb_schema.ts     |  3 ++-
 .../test/unit/local/schema_migration.test.ts         | 12 ++++--------
 2 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/packages/firestore/src/local/indexeddb_schema.ts b/packages/firestore/src/local/indexeddb_schema.ts
index eabc16a7a31..d479971e884 100644
--- a/packages/firestore/src/local/indexeddb_schema.ts
+++ b/packages/firestore/src/local/indexeddb_schema.ts
@@ -563,7 +563,8 @@ function createClientMetadataStore(db: IDBDatabase): void {
   });
 }
 
-const V1_STORES = [
+// Visible for testing
+export const V1_STORES = [
   DbMutationQueue.store,
   DbMutationBatch.store,
   DbDocumentMutation.store,
diff --git a/packages/firestore/test/unit/local/schema_migration.test.ts b/packages/firestore/test/unit/local/schema_migration.test.ts
index eebf315f474..4197d5435d8 100644
--- a/packages/firestore/test/unit/local/schema_migration.test.ts
+++ b/packages/firestore/test/unit/local/schema_migration.test.ts
@@ -18,8 +18,7 @@ import { expect } from 'chai';
 import { IndexedDbPersistence } from '../../../src/local/indexeddb_persistence';
 import {
   DEFAULT_STORES,
-  createOrUpgradeDb,
-  ALL_STORES
+  createOrUpgradeDb, V1_STORES,
 } from '../../../src/local/indexeddb_schema';
 import { Deferred } from '../../../src/util/promise';
 import { SimpleDb } from '../../../src/local/simple_db';
@@ -45,9 +44,6 @@ function withDb(schemaVersion, fn: (db: IDBDatabase) => void): Promise<void> {
   })
     .then(db => {
       fn(db);
-      return db;
-    })
-    .then(db => {
       db.close();
     });
 }
@@ -72,14 +68,14 @@ describe('IndexedDbSchema: createOrUpgradeDb', () => {
   it('can install schema version 1', () => {
     return withDb(1, db => {
       expect(db.version).to.be.equal(1);
-      expect(getAllObjectStores(db)).to.have.members(DEFAULT_STORES);
+      expect(getAllObjectStores(db)).to.have.members(V1_STORES);
     });
   });
 
   it('can install schema version 2', () => {
     return withDb(2, db => {
       expect(db.version).to.be.equal(2);
-      expect(getAllObjectStores(db)).to.have.members(ALL_STORES);
+      expect(getAllObjectStores(db)).to.have.members(DEFAULT_STORES);
     });
   });
 
@@ -87,7 +83,7 @@ describe('IndexedDbSchema: createOrUpgradeDb', () => {
     return withDb(1, () => {}).then(() =>
       withDb(2, db => {
         expect(db.version).to.be.equal(2);
-        expect(getAllObjectStores(db)).to.have.members(ALL_STORES);
+        expect(getAllObjectStores(db)).to.have.members(DEFAULT_STORES);
       })
     );
   });

From b70303cb7ad896e7c96106f145f960662b9219a6 Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Thu, 8 Feb 2018 18:24:55 -0800
Subject: [PATCH 21/22] [AUTOMATED]: Prettier Code Styling

---
 .../test/unit/local/schema_migration.test.ts         | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/packages/firestore/test/unit/local/schema_migration.test.ts b/packages/firestore/test/unit/local/schema_migration.test.ts
index 4197d5435d8..c98bf579bae 100644
--- a/packages/firestore/test/unit/local/schema_migration.test.ts
+++ b/packages/firestore/test/unit/local/schema_migration.test.ts
@@ -18,7 +18,8 @@ import { expect } from 'chai';
 import { IndexedDbPersistence } from '../../../src/local/indexeddb_persistence';
 import {
   DEFAULT_STORES,
-  createOrUpgradeDb, V1_STORES,
+  createOrUpgradeDb,
+  V1_STORES
 } from '../../../src/local/indexeddb_schema';
 import { Deferred } from '../../../src/util/promise';
 import { SimpleDb } from '../../../src/local/simple_db';
@@ -41,11 +42,10 @@ function withDb(schemaVersion, fn: (db: IDBDatabase) => void): Promise<void> {
     request.onerror = (event: ErrorEvent) => {
       reject((event.target as IDBOpenDBRequest).error);
     };
-  })
-    .then(db => {
-      fn(db);
-      db.close();
-    });
+  }).then(db => {
+    fn(db);
+    db.close();
+  });
 }
 
 function getAllObjectStores(db: IDBDatabase): String[] {

From 34ab25aae677f0151fffc4f269190811cd52e3e7 Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <mrschmidt@google.com>
Date: Fri, 9 Feb 2018 10:03:15 -0800
Subject: [PATCH 22/22] Renamed to ALL_STORES

---
 packages/firestore/src/local/indexeddb_persistence.ts       | 4 ++--
 packages/firestore/src/local/indexeddb_schema.ts            | 2 +-
 packages/firestore/test/unit/local/schema_migration.test.ts | 6 +++---
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/packages/firestore/src/local/indexeddb_persistence.ts b/packages/firestore/src/local/indexeddb_persistence.ts
index 3dc3e287495..b09548e5e2b 100644
--- a/packages/firestore/src/local/indexeddb_persistence.ts
+++ b/packages/firestore/src/local/indexeddb_persistence.ts
@@ -26,7 +26,7 @@ import { IndexedDbMutationQueue } from './indexeddb_mutation_queue';
 import { IndexedDbQueryCache } from './indexeddb_query_cache';
 import { IndexedDbRemoteDocumentCache } from './indexeddb_remote_document_cache';
 import {
-  DEFAULT_STORES,
+  ALL_STORES,
   createOrUpgradeDb,
   DbOwner,
   DbOwnerKey,
@@ -177,7 +177,7 @@ export class IndexedDbPersistence implements Persistence {
 
     // Do all transactions as readwrite against all object stores, since we
     // are the only reader/writer.
-    return this.simpleDb.runTransaction('readwrite', DEFAULT_STORES, txn => {
+    return this.simpleDb.runTransaction('readwrite', ALL_STORES, txn => {
       // Verify that we still have the owner lease as part of every transaction.
       return this.ensureOwnerLease(txn).next(() => operation(txn));
     });
diff --git a/packages/firestore/src/local/indexeddb_schema.ts b/packages/firestore/src/local/indexeddb_schema.ts
index d479971e884..d3689ff94f1 100644
--- a/packages/firestore/src/local/indexeddb_schema.ts
+++ b/packages/firestore/src/local/indexeddb_schema.ts
@@ -582,4 +582,4 @@ const V2_STORES = [DbClientMetadata.store, DbTargetChange.store];
  * used when creating transactions so that access across all stores is done
  * atomically.
  */
-export const DEFAULT_STORES = [...V1_STORES, ...V2_STORES];
+export const ALL_STORES = [...V1_STORES, ...V2_STORES];
diff --git a/packages/firestore/test/unit/local/schema_migration.test.ts b/packages/firestore/test/unit/local/schema_migration.test.ts
index c98bf579bae..3faad875333 100644
--- a/packages/firestore/test/unit/local/schema_migration.test.ts
+++ b/packages/firestore/test/unit/local/schema_migration.test.ts
@@ -17,7 +17,7 @@
 import { expect } from 'chai';
 import { IndexedDbPersistence } from '../../../src/local/indexeddb_persistence';
 import {
-  DEFAULT_STORES,
+  ALL_STORES,
   createOrUpgradeDb,
   V1_STORES
 } from '../../../src/local/indexeddb_schema';
@@ -75,7 +75,7 @@ describe('IndexedDbSchema: createOrUpgradeDb', () => {
   it('can install schema version 2', () => {
     return withDb(2, db => {
       expect(db.version).to.be.equal(2);
-      expect(getAllObjectStores(db)).to.have.members(DEFAULT_STORES);
+      expect(getAllObjectStores(db)).to.have.members(ALL_STORES);
     });
   });
 
@@ -83,7 +83,7 @@ describe('IndexedDbSchema: createOrUpgradeDb', () => {
     return withDb(1, () => {}).then(() =>
       withDb(2, db => {
         expect(db.version).to.be.equal(2);
-        expect(getAllObjectStores(db)).to.have.members(DEFAULT_STORES);
+        expect(getAllObjectStores(db)).to.have.members(ALL_STORES);
       })
     );
   });