Release operation permit on thread-pool rejection #25930
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
ywelsch
added
:Core/Infra/Core
bleskes
suggested changes
Jul 27, 2017
There was a problem hiding this comment.
The code LGTM in sense that it does the right thing while maintaining the old behavior of the generic ThreadedActionListener. However, in this case, I'm a bit concerned about the number of options in which the failure handler can be called - sometimes on the requested executor, sometimes on the generic thread and some times on the original thread - so there is really no guarantee on what's "safe" to do there. I wonder if we should make it simpler code wise and say that the executor on holds for onResponse. The failure handler can be called on arbitrary threads and should only be used for light weight work (which we do). WDYT?
|
|
||
| @Override | ||
| public void onFailure(Exception e) { | ||
| listener.onFailure(e); // will possibly execute on the generic thread spawned off in releaseDelayedOperations |
There was a problem hiding this comment.
should we release the releasable just in case the exception comes from the listener? this would allow us to only implement on failure.
There was a problem hiding this comment.
It is the responsibility of the wrapped listener to make sure to free the permit when encountering an exception in its onResponse method. I prefer the code to be more explicit here instead of mixing two failures paths.
|
|
||
| @Override | ||
| public void onFailure(Exception e) { | ||
| listener.onFailure(e); // will possibly execute on the generic thread spawned off in releaseDelayedOperations |
There was a problem hiding this comment.
In the case of rejection, I think we want to add the original exception as "suppressed"?
There was a problem hiding this comment.
This comment becomes obsolete by running the PermitAwareThreadedActionListener.onFailure() method on the caller thread.
| @@ -59,7 +63,18 @@ | |||
|
|
|||
| @BeforeClass | |||
| public static void setupThreadPool() { | |||
| threadPool = new TestThreadPool("IndexShardOperationsLockTests"); | |||
| int bulkThreadPoolSize = randomIntBetween(1, 2); | |||
There was a problem hiding this comment.
++ to randomly use limited capacity.
|
Thanks @bleskes |
ywelsch
added a commit
that referenced
this pull request
Jul 27, 2017
At the shard level we use an operation permit to coordinate between regular shard operations and special operations that need exclusive access. In ES versions < 6, the operation requiring exclusive access was invoked during primary relocation, but ES versions >= 6 this exclusive access is also used when a replica learns about a new primary or when a replica is promoted to primary. These special operations requiring exclusive access delay regular operations from running, by adding them to a queue, and after finishing the exclusive access, release these operations which then need to be put back on the original thread-pool they were running on. In the presence of thread pool rejections, the current implementation had two issues: - it would not properly release the operation permit when hitting a rejection (i.e. when calling ThreadedActionListener.onResponse from IndexShardOperationPermits.acquire). - it would not invoke the onFailure method of the action listener when the shard was closed, and just log a warning instead (see ThreadedActionListener.onFailure), which would ultimately lead to the replication task never being cleaned up (see #25863). This commit fixes both issues by introducing a custom threaded action listener that is permit-aware and properly deals with rejections. Closes #25863
ywelsch
added a commit
that referenced
this pull request
Jul 27, 2017
At the shard level we use an operation permit to coordinate between regular shard operations and special operations that need exclusive access. In ES versions < 6, the operation requiring exclusive access was invoked during primary relocation, but ES versions >= 6 this exclusive access is also used when a replica learns about a new primary or when a replica is promoted to primary. These special operations requiring exclusive access delay regular operations from running, by adding them to a queue, and after finishing the exclusive access, release these operations which then need to be put back on the original thread-pool they were running on. In the presence of thread pool rejections, the current implementation had two issues: - it would not properly release the operation permit when hitting a rejection (i.e. when calling ThreadedActionListener.onResponse from IndexShardOperationPermits.acquire). - it would not invoke the onFailure method of the action listener when the shard was closed, and just log a warning instead (see ThreadedActionListener.onFailure), which would ultimately lead to the replication task never being cleaned up (see #25863). This commit fixes both issues by introducing a custom threaded action listener that is permit-aware and properly deals with rejections. Closes #25863
ywelsch
added a commit
that referenced
this pull request
Jul 27, 2017
At the shard level we use an operation permit to coordinate between regular shard operations and special operations that need exclusive access. In ES versions < 6, the operation requiring exclusive access was invoked during primary relocation, but ES versions >= 6 this exclusive access is also used when a replica learns about a new primary or when a replica is promoted to primary. These special operations requiring exclusive access delay regular operations from running, by adding them to a queue, and after finishing the exclusive access, release these operations which then need to be put back on the original thread-pool they were running on. In the presence of thread pool rejections, the current implementation had two issues: - it would not properly release the operation permit when hitting a rejection (i.e. when calling ThreadedActionListener.onResponse from IndexShardOperationPermits.acquire). - it would not invoke the onFailure method of the action listener when the shard was closed, and just log a warning instead (see ThreadedActionListener.onFailure), which would ultimately lead to the replication task never being cleaned up (see #25863). This commit fixes both issues by introducing a custom threaded action listener that is permit-aware and properly deals with rejections. Closes #25863
ywelsch
added a commit
that referenced
this pull request
Jul 27, 2017
At the shard level we use an operation permit to coordinate between regular shard operations and special operations that need exclusive access. In ES versions < 6, the operation requiring exclusive access was invoked during primary relocation, but ES versions >= 6 this exclusive access is also used when a replica learns about a new primary or when a replica is promoted to primary. These special operations requiring exclusive access delay regular operations from running, by adding them to a queue, and after finishing the exclusive access, release these operations which then need to be put back on the original thread-pool they were running on. In the presence of thread pool rejections, the current implementation had two issues: - it would not properly release the operation permit when hitting a rejection (i.e. when calling ThreadedActionListener.onResponse from IndexShardOperationPermits.acquire). - it would not invoke the onFailure method of the action listener when the shard was closed, and just log a warning instead (see ThreadedActionListener.onFailure), which would ultimately lead to the replication task never being cleaned up (see #25863). This commit fixes both issues by introducing a custom threaded action listener that is permit-aware and properly deals with rejections. Closes #25863
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
At the shard level we use an operation permit to coordinate between regular shard operations and special operations that need exclusive access. In ES versions < 6, the operation requiring exclusive access was invoked during primary relocation, but ES versions >= 6 this exclusive access is also used when a replica learns about a new primary or when a replica is promoted to primary.
These special operations requiring exclusive access delay regular operations from running, by adding them to a queue, and after finishing the exclusive access, release these operations which then need to be put back on the original thread-pool they were running on. In the presence of thread pool rejections, the current implementation had two issues:
ThreadedActionListener.onResponsefromIndexShardOperationPermits.acquire).ThreadedActionListener.onFailure), which would ultimately lead to the replication task never being cleaned up (see Tasks stuck forever #25863).This PR fixes both issues by introducing a custom threaded action listener that is permit-aware and properly deals with rejections.
Closes #25863