Support deleteAllIndexes in PersistentCacheIndexManager (#5162)

* Add counter

* address feedback 1

* implement autoClientIndexing

* Add tests and fix bugs for BuildTargetIndex

* hide getter from public API

* move the flag from IndexManager to QueryEngine

* move auto index flag to runtime

* Support old way to enable persistent for PersistentCacheManager

* Add hide and copyright

* Rename PersistentCacheManager to PersistentCacheIndexManager

* add configurable min documents to create indexes

* Address feedback

* Add deleteAllIndexes

* Add documentation

* add test coverage

* merge main branch

Author: cherylEnkidu

firebase-firestore/src/androidTest/java/com/google/firebase/firestore/IndexingTest.java

@@ -136,6 +136,9 @@ public void testAutoIndexCreationSetSuccessfully() {
 
     results = waitFor(collection.whereEqualTo("match", true).get());
     assertEquals(1, results.size());
+
+    assertDoesNotThrow(() -> db.getPersistentCacheIndexManager().deleteAllIndexes());
+    assertEquals(1, results.size());
   }
 
   @Test
@@ -161,6 +164,9 @@ public void testAutoIndexCreationSetSuccessfullyUsingDefault() {
 
     results = waitFor(collection.whereEqualTo("match", true).get());
     assertEquals(1, results.size());
+
+    assertDoesNotThrow(() -> db.getPersistentCacheIndexManager().deleteAllIndexes());
+    assertEquals(1, results.size());
   }
 
   @Test
@@ -175,5 +181,9 @@ public void testAutoIndexCreationAfterFailsTermination() {
     expectError(
         () -> db.getPersistentCacheIndexManager().disableIndexAutoCreation(),
         "The client has already been terminated");
+
+    expectError(
+        () -> db.getPersistentCacheIndexManager().deleteAllIndexes(),
+        "The client has already been terminated");
   }
 }

firebase-firestore/src/main/java/com/google/firebase/firestore/PersistentCacheIndexManager.java

@@ -51,4 +51,12 @@ public void enableIndexAutoCreation() {
   public void disableIndexAutoCreation() {
     client.setIndexAutoCreationEnabled(false);
   }
+
+  /**
+   * Removes all persistent cache indexes. Please note this function will also deletes indexes
+   * generated by {@link FirebaseFirestore#setIndexConfiguration(String)}, which is deprecated.
+   */
+  public void deleteAllIndexes() {
+    client.deleteAllFieldIndexes();
+  }
 }

firebase-firestore/src/main/java/com/google/firebase/firestore/core/FirestoreClient.java

@@ -358,6 +358,11 @@ public void setIndexAutoCreationEnabled(boolean enabled) {
     asyncQueue.enqueueAndForget(() -> localStore.setIndexAutoCreationEnabled(enabled));
   }
 
+  public void deleteAllFieldIndexes() {
+    verifyNotTerminated();
+    asyncQueue.enqueueAndForget(() -> localStore.deleteAllFieldIndexes());
+  }
+
   public void removeSnapshotsInSyncListener(EventListener<Void> listener) {
     // Checks for shutdown but does not raise error, allowing remove after shutdown to be a no-op.
     if (isTerminated()) {

firebase-firestore/src/main/java/com/google/firebase/firestore/local/IndexManager.java

@@ -78,6 +78,9 @@ enum IndexType {
   /** Removes the given field index and deletes all index values. */
   void deleteFieldIndex(FieldIndex index);
 
+  /** Removes all field indexes and deletes all index values. */
+  void deleteAllFieldIndexes();
+
   /** Creates a full matched field index which serves the given target. */
   void createTargetIndexes(Target target);
 

firebase-firestore/src/main/java/com/google/firebase/firestore/local/LocalStore.java

@@ -802,6 +802,10 @@ public void configureFieldIndexes(List<FieldIndex> newFieldIndexes) {
         });
   }
 
+  public void deleteAllFieldIndexes() {
+    persistence.runTransaction("Delete All Indexes", () -> indexManager.deleteAllFieldIndexes());
+  }
+
   public void setIndexAutoCreationEnabled(boolean enabled) {
     queryEngine.setIndexAutoCreationEnabled(enabled);
   }

firebase-firestore/src/main/java/com/google/firebase/firestore/local/MemoryIndexManager.java

@@ -60,6 +60,11 @@ public void deleteFieldIndex(FieldIndex index) {
     // Field indices are not supported with memory persistence.
   }
 
+  @Override
+  public void deleteAllFieldIndexes() {
+    // Field indices are not supported with memory persistence.
+  }
+
   @Override
   public void createTargetIndexes(Target target) {}
 

firebase-firestore/src/main/java/com/google/firebase/firestore/local/SQLiteIndexManager.java

@@ -233,6 +233,16 @@ public void deleteFieldIndex(FieldIndex index) {
     }
   }
 
+  @Override
+  public void deleteAllFieldIndexes() {
+    db.execute("DELETE FROM index_configuration");
+    db.execute("DELETE FROM index_entries");
+    db.execute("DELETE FROM index_state");
+
+    nextIndexToUpdate.clear();
+    memoizedIndexes.clear();
+  }
+
   @Override
   public void createTargetIndexes(Target target) {
     hardAssert(started, "IndexManager not started");

firebase-firestore/src/test/java/com/google/firebase/firestore/local/LocalStoreTestCase.java

@@ -234,6 +234,10 @@ protected void setRelativeIndexReadCostPerDocument(double newCost) {
     queryEngine.setRelativeIndexReadCostPerDocument(newCost);
   }
 
+  protected void deleteAllIndexes() {
+    localStore.deleteAllFieldIndexes();
+  }
+
   private void releaseTarget(int targetId) {
     localStore.releaseTarget(targetId);
   }

firebase-firestore/src/test/java/com/google/firebase/firestore/local/SQLiteLocalStoreTest.java

@@ -575,6 +575,68 @@ public void testDisableIndexAutoCreationWorks() {
     assertRemoteDocumentsRead(/* byKey= */ 0, /* byCollection= */ 2);
   }
 
+  @Test
+  public void testDeleteAllIndexesWorksWithIndexAutoCreation() {
+    Query query = query("coll").filter(filter("value", "==", "match"));
+    int targetId = allocateQuery(query);
+
+    setIndexAutoCreationEnabled(true);
+    setMinCollectionSizeToAutoCreateIndex(0);
+    setRelativeIndexReadCostPerDocument(2);
+
+    applyRemoteEvent(addedRemoteEvent(doc("coll/a", 10, map("value", "match")), targetId));
+    applyRemoteEvent(addedRemoteEvent(doc("coll/b", 10, map("value", Double.NaN)), targetId));
+    applyRemoteEvent(addedRemoteEvent(doc("coll/c", 10, map("value", null)), targetId));
+    applyRemoteEvent(addedRemoteEvent(doc("coll/d", 10, map("value", "mismatch")), targetId));
+    applyRemoteEvent(addedRemoteEvent(doc("coll/e", 10, map("value", "match")), targetId));
+
+    // First time query is running without indexes.
+    // Based on current heuristic, collection document counts (5) > 2 * resultSize (2).
+    // Full matched index should be created.
+    executeQuery(query);
+    assertRemoteDocumentsRead(/* byKey= */ 0, /* byCollection= */ 2);
+    assertQueryReturned("coll/a", "coll/e");
+
+    setIndexAutoCreationEnabled(false);
+
+    backfillIndexes();
+
+    executeQuery(query);
+    assertRemoteDocumentsRead(/* byKey= */ 2, /* byCollection= */ 0);
+    assertQueryReturned("coll/a", "coll/e");
+
+    deleteAllIndexes();
+
+    executeQuery(query);
+    assertRemoteDocumentsRead(/* byKey= */ 0, /* byCollection= */ 2);
+    assertQueryReturned("coll/a", "coll/e");
+  }
+
+  @Test
+  public void testDeleteAllIndexesWorksWithManualAddedIndexes() {
+    FieldIndex index =
+        fieldIndex(
+            "coll", 0, FieldIndex.INITIAL_STATE, "matches", FieldIndex.Segment.Kind.ASCENDING);
+    configureFieldIndexes(singletonList(index));
+
+    Query query = query("coll").filter(filter("matches", "==", true));
+    int targetId = allocateQuery(query);
+
+    applyRemoteEvent(addedRemoteEvent(doc("coll/a", 10, map("matches", true)), targetId));
+
+    backfillIndexes();
+
+    executeQuery(query);
+    assertRemoteDocumentsRead(/* byKey= */ 1, /* byCollection= */ 0);
+    assertQueryReturned("coll/a");
+
+    deleteAllIndexes();
+
+    executeQuery(query);
+    assertRemoteDocumentsRead(/* byKey= */ 0, /* byCollection= */ 1);
+    assertQueryReturned("coll/a");
+  }
+
   @Test
   public void testIndexAutoCreationWorksWithMutation() {
     Query query =