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Posted to issues@ignite.apache.org by "Aleksey Plekhanov (Jira)" <ji...@apache.org> on 2021/07/15 12:20:00 UTC
[jira] [Commented] (IGNITE-15099) Wrong heartbeat update while
waiting for a checkpoint by timeout
[ https://issues.apache.org/jira/browse/IGNITE-15099?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17381307#comment-17381307 ]
Aleksey Plekhanov commented on IGNITE-15099:
--------------------------------------------
[~shishkovilja], can you please have a look at the patch?
> Wrong heartbeat update while waiting for a checkpoint by timeout
> ----------------------------------------------------------------
>
> Key: IGNITE-15099
> URL: https://issues.apache.org/jira/browse/IGNITE-15099
> Project: Ignite
> Issue Type: Bug
> Affects Versions: 2.11, 2.12
> Reporter: Ilya Shishkov
> Assignee: Aleksey Plekhanov
> Priority: Minor
> Labels: ise
> Attachments: Checkpointer_fake_block_master.patch
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> This problem occurs under these conditions:
> * native persistence is turned on
> * failureDetectionTimeout < checkpointFrequency
> * checkpoints are sometimes skipped by timeout (more often, more probable the problem occurrence)
> There is a race condition between a listener execution and finishing of a pending future (see CheckpointContextImpl#executor body [1]). In some cases future can finish before listener closure, therefore updating of a heartbeat in listener can occur after call of _blockingSectionBegin_ in Checkpointer#waitCheckpointEvent, i.e. after Checkpointer started to wait for next checkpoint (see [2]).
> {code:java|title=CheckpointContextImpl#executor}
> @Override public Executor executor() {
> return asyncRunner == null ? null : cmd -> {
> try {
> GridFutureAdapter<?> res = new GridFutureAdapter<>();
> res.listen(fut -> heartbeatUpdater.updateHeartbeat()); // Listener is invoked concurrently with pending future finish
> asyncRunner.execute(U.wrapIgniteFuture(cmd, res));
> pendingTaskFuture.add(res);
> }
> catch (RejectedExecutionException e) {
> assert false : "A task should never be rejected by async runner";
> }
> };
> }
> {code}
> {code:java|title=Checkpointer#waitCheckpointEvent}
> try {
> synchronized (this) {
> long remaining = U.nanosToMillis(scheduledCp.nextCpNanos - System.nanoTime());
> while (remaining > 0 && !isCancelled()) {
> blockingSectionBegin();
> try {
> wait(remaining);
> // At this point and till blockingSectionEnd call heartbeat should be equal to Long.MAX_VALUE
> remaining = U.nanosToMillis(scheduledCp.nextCpNanos - System.nanoTime());
> }
> finally {
> blockingSectionEnd();
> }
> }
> }
> }
> {code}
>
> If interval between checkpoints (_checkpointFrequency_) is greater than the _failureDetectionTimeout_, then update of heartbeat in _blockingSectionEnd_ may cause an error message in log, because a checkpoint thread is treated as blocked (but in fact it was not).
> *Reproducer of problem:* [3]. Even if test was not failed you can see log message with incorrect heartbeat after waiting for checkpoint.
>
> Links:
> # [CheckpointContextImpl#executor|https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/persistence/checkpoint/CheckpointContextImpl.java#L104]
> # [Checkpointer#waitCheckpointEvent|https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/persistence/checkpoint/Checkpointer.java#L816]
> # Reproducer: [^Checkpointer_fake_block_master.patch].
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