send write requests early if the pipeline is full and contains only unsent write requests

Author: dconeybe

packages/firestore/src/api/experimental_options.ts

@@ -38,8 +38,8 @@ export interface ExperimentalOptions {
    * _could_ greatly reduce the number of distinct HTTP requests that are used.
    *
    * The value must be an integer value strictly greater than zero and less than
-   * or equal to 2000 (2 seconds). A value of `200` is a good starting point to
-   * minimize write latency yet still enable a some amount of batching.
+   * or equal to 10000 (10 seconds). A value of `200` is a good starting point
+   * to minimize write latency yet still enable some amount of batching.
    *
    * See https://github.com/firebase/firebase-js-sdk/issues/5971 for rationale
    * and background information that motivated this option.

packages/firestore/src/lite-api/settings.ts

@@ -55,7 +55,9 @@ const MAX_LONG_POLLING_TIMEOUT_SECONDS = 30;
 // Whether long-polling auto-detected is enabled by default.
 const DEFAULT_AUTO_DETECT_LONG_POLLING = true;
 
-const MAX_SEND_WRITE_REQUEST_DELAY_MS = 2000;
+// Set some maximum value for `sendWriteRequestsDelayMs` to avoid it being set
+// to a value so large that it appears that write requests are never being sent.
+const MAX_SEND_WRITE_REQUEST_DELAY_MS = 10000;
 
 /**
  * Specifies custom configurations for your Cloud Firestore instance.

packages/firestore/src/remote/remote_store.ts

@@ -764,7 +764,14 @@ function addToWritePipeline(
     writeRequestSent: false
   });
 
-  if (remoteStoreImpl.sendWriteRequestsDelayMs === null) {
+  const writePipelineContainsOnlyUnsentWriteRequests =
+    remoteStoreImpl.writePipeline.every(entry => !entry.writeRequestSent);
+
+  if (
+    remoteStoreImpl.sendWriteRequestsDelayMs === null ||
+    (!canAddToWritePipeline(remoteStoreImpl) &&
+      writePipelineContainsOnlyUnsentWriteRequests)
+  ) {
     remoteStoreImpl.sendWriteRequestsOperation?.cancel();
     remoteStoreImpl.sendWriteRequestsOperation = null;
     sendWriteRequestsFromPipeline(remoteStoreImpl);