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zhongkechen · 2026-02-10T07:34:43Z

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

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Description

Added two parameters to DurableConfig: PollingInterval (default: 1s) and CheckpointDelay (default: 0)
Added a helper class ApiRequestBatcher to call API with items in batch
Added a method pollForUpdate to CheckpointBatcher that allows operations to poll updates from backend for specific operations.
Changed the behavior of polling updates. No thread will be created when an operation polling for updates. Instead, a future will be registered in CheckpointBatcher and completes when an update of the operation is received.
Changed the thread requirements in the internal thread pool. One background thread will be run to poll the updates for all operations.
Replaced pollUntilReady with pollForOperationUpdates
Removed "DAR" from code

Demo/Screenshots

[INFO] AWS Lambda Durable Execution SDK Parent ............ SUCCESS [  0.420 s]
[INFO] AWS Lambda Durable Execution SDK for Java .......... SUCCESS [ 43.037 s]
[INFO] AWS Lambda Durable Execution SDK Testing Utilities . SUCCESS [ 19.164 s]
[INFO] AWS Lambda Durable Execution SDK Integration Tests . SUCCESS [01:27 min]
[INFO] AWS Lambda Durable Execution SDK Examples .......... SUCCESS [01:13 min]

[INFO] Results:
[INFO] 
[INFO] Tests run: 14, Failures: 0, Errors: 0, Skipped: 0

Checklist

I have filled out every section of the PR template
I have thoroughly tested this change

Testing

Unit Tests

Have unit tests been written for these changes? yes

Integration Tests

Have integration tests been written for these changes? N/A

Examples

Has a new example been added for the change? (if applicable) will follow up with an example of using customized polling interval config/checkpoint config

sdk/src/main/java/com/amazonaws/lambda/durable/execution/CheckpointBatcher.java

zhongkechen · 2026-02-10T20:38:27Z

sdk/src/main/java/com/amazonaws/lambda/durable/execution/CheckpointBatcher.java

-    private final AtomicBoolean isProcessing = new AtomicBoolean(false);
+    private final AtomicBoolean isRunning = new AtomicBoolean(true);
+    private final Duration pollingInterval;
+    private final Map<String, List<CompletableFuture<Operation>>> pollingFutures = new ConcurrentHashMap<>();


Not too sure if one operation can poll more than once. Using a list here for this case

sdk/src/main/java/com/amazonaws/lambda/durable/operation/BaseDurableOperation.java

examples/src/main/resources/log4j2.xml

SilanHe · 2026-02-13T21:47:53Z

sdk/src/main/java/com/amazonaws/lambda/durable/execution/CheckpointBatcher.java

 */
 class CheckpointBatcher {
    private static final int MAX_BATCH_SIZE_BYTES = 750 * 1024; // 750KB
+    private static final int MAX_ITEM_COUNT = 100; // max updates in one batch


This is pretty conservative, I think Python and JS are using 250, that said it is just a number we picked:

aws/aws-durable-execution-sdk-js#427
aws/aws-durable-execution-sdk-python#281

SilanHe · 2026-02-13T21:48:46Z

sdk/src/main/java/com/amazonaws/lambda/durable/execution/CheckpointBatcher.java

+                MAX_ITEM_COUNT, MAX_BATCH_SIZE_BYTES, CheckpointBatcher::estimateSize, this::checkpointBatch);
    }

+    /** Queues a checkpoint request for batched execution */


what's a "batched execution"?

Good catch.

This sounds better:

Queues an operation update for batched checkpoint

SilanHe · 2026-02-13T22:30:03Z

sdk/src/main/java/com/amazonaws/lambda/durable/operation/WaitOperation.java

-        // The polling will complete the phaser when the backend reports SUCCEEDED
-        Instant firstPoll = Instant.now().plus(remainingWaitTime).plusMillis(25);
-        pollForOperationUpdates(firstPoll, Duration.ofMillis(200));
+        pollForOperationUpdates(remainingWaitTime);


I don't get it, why do we need to poll for updates?

So basically, we need to "poll" CheckpointDurableExecution because we're doing this checkpoint operation batching? Wouldn't the future on the operation complete complete and allow the code to keep executing?

If the execution doesn't get suspended (some async steps running), SDK needs to poll the updates for the operations like in this case for Wait. pollForOperationUpdates here just register a poller so that the CheckpointBatcher will keep polling until we receive an update for this operation.

zhongkechen self-assigned this Feb 10, 2026

zhongkechen added the work in progress label Feb 10, 2026

zhongkechen changed the title ~~[refactor] Optimize Poller~~ [refactor] Optimize Poller [WIP] Feb 10, 2026

zhongkechen force-pushed the poller branch from 8005ec7 to 6953ac3 Compare February 10, 2026 19:33

zhongkechen added 2 commits February 10, 2026 12:15

optimize pollers

15e5859

add async batcher to call checkpoint API with a delay

805a846

zhongkechen force-pushed the poller branch from 6953ac3 to 805a846 Compare February 10, 2026 20:16

update the comments

d396bec

zhongkechen commented Feb 10, 2026

View reviewed changes

sdk/src/main/java/com/amazonaws/lambda/durable/execution/CheckpointBatcher.java Show resolved Hide resolved

zhongkechen commented Feb 10, 2026

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sdk/src/main/java/com/amazonaws/lambda/durable/operation/BaseDurableOperation.java Show resolved Hide resolved

zhongkechen added 4 commits February 10, 2026 14:06

add tests for batcher

34c79a8

rename methods/fields and update comments

2523bd9

remove locker from batcher

9eea0c7

fix race condition

5fe2153

zhongkechen changed the title ~~[refactor] Optimize Poller [WIP]~~ [refactor] Optimize Poller Feb 11, 2026

zhongkechen requested review from maschnetwork and phipag February 11, 2026 06:09

zhongkechen added 2 commits February 10, 2026 22:18

fix exception handling

15b80a1

fix flush now issue

2390a04

zhongkechen removed the work in progress label Feb 11, 2026

zhongkechen marked this pull request as ready for review February 11, 2026 06:40

zhongkechen changed the title ~~[refactor] Optimize Poller~~ [improvement] Optimize Poller Feb 11, 2026

zhongkechen added 7 commits February 11, 2026 16:37

allow operation specific poll time

d66a854

poll again if the previous poll doesn't receive an update

a6df5b2

Merge remote-tracking branch 'origin/main' into poller

909ff58

improve shutdown of checkpointBatcher

e4f9cd9

add latencies to logs

f96b765

update some comments

0eea379

fix the checkpoint delay

997675f

update some comments

622ef31

SilanHe approved these changes Feb 13, 2026

View reviewed changes

zhongkechen merged commit c4f440f into main Feb 13, 2026
9 of 13 checks passed

zhongkechen deleted the poller branch February 13, 2026 23:03

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[improvement] Optimize Poller#69

[improvement] Optimize Poller#69
zhongkechen merged 17 commits intomainfrom
poller

zhongkechen commented Feb 10, 2026 •

edited

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zhongkechen commented Feb 10, 2026 •

edited

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