[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
[ https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16781377#comment-16781377 ] Michael Dürig commented on OAK-8071: Fix for 1.10: http://svn.apache.org/viewvc?rev=1854559&view=rev Fix for 1.8: http://svn.apache.org/viewvc?rev=1854560&view=rev > Logging to detect commits carrying over from previous GC generation can block > other threads from committing > --- > > Key: OAK-8071 > URL: https://issues.apache.org/jira/browse/OAK-8071 > Project: Jackrabbit Oak > Issue Type: Technical task > Components: segment-tar >Reporter: Michael Dürig >Assignee: Michael Dürig >Priority: Blocker > Fix For: 1.12, 1.11.0, 1.8.12, 1.10.2 > > > Add logging / monitoring to detect the situation from OAK-8014. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
[ https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16780553#comment-16780553 ] Michael Dürig commented on OAK-8071: [~reschke], this should still be blocking the release for the 1.10 and 1.8 branches. This I'd rather leave it open until backported. ETA: tomorrow morning (UTC+1). > Logging to detect commits carrying over from previous GC generation can block > other threads from committing > --- > > Key: OAK-8071 > URL: https://issues.apache.org/jira/browse/OAK-8071 > Project: Jackrabbit Oak > Issue Type: Technical task > Components: segment-tar >Reporter: Michael Dürig >Assignee: Michael Dürig >Priority: Blocker > Fix For: 1.12, 1.11.0, 1.8.12, 1.10.2 > > > Add logging / monitoring to detect the situation from OAK-8014. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
[ https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16780532#comment-16780532 ] Julian Reschke commented on OAK-8071: - If this is fixed in trunk, the ticket should be set to "resolved". > Logging to detect commits carrying over from previous GC generation can block > other threads from committing > --- > > Key: OAK-8071 > URL: https://issues.apache.org/jira/browse/OAK-8071 > Project: Jackrabbit Oak > Issue Type: Technical task > Components: segment-tar >Reporter: Michael Dürig >Assignee: Michael Dürig >Priority: Blocker > Fix For: 1.12, 1.11.0, 1.8.12, 1.10.2 > > > Add logging / monitoring to detect the situation from OAK-8014. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
[ https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16780390#comment-16780390 ] Michael Dürig commented on OAK-8071: I filed OAK-8094 to follow up on the JMX part. > Logging to detect commits carrying over from previous GC generation can block > other threads from committing > --- > > Key: OAK-8071 > URL: https://issues.apache.org/jira/browse/OAK-8071 > Project: Jackrabbit Oak > Issue Type: Technical task > Components: segment-tar >Reporter: Michael Dürig >Assignee: Michael Dürig >Priority: Blocker > Fix For: 1.12, 1.11.0, 1.8.12, 1.10.2 > > > Add logging / monitoring to detect the situation from OAK-8014. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
[ https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16780330#comment-16780330 ] Michael Dürig commented on OAK-8071: Fixed in trunk at http://svn.apache.org/viewvc?rev=1854515&view=rev > Logging to detect commits carrying over from previous GC generation can block > other threads from committing > --- > > Key: OAK-8071 > URL: https://issues.apache.org/jira/browse/OAK-8071 > Project: Jackrabbit Oak > Issue Type: Technical task > Components: segment-tar >Reporter: Michael Dürig >Assignee: Michael Dürig >Priority: Blocker > Fix For: 1.12, 1.11.0, 1.8.12, 1.10.2 > > > Add logging / monitoring to detect the situation from OAK-8014. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
[ https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16780251#comment-16780251 ] Michael Dürig commented on OAK-8071: Thanks [~ahanikel] for the review. I will thus go forward with the changes from https://github.com/mduerig/jackrabbit-oak/commits/OAK-8071-logging here. I will move the patched proposed on the other branch for improving the JMX monitoring into a new issue of type improvement. > Logging to detect commits carrying over from previous GC generation can block > other threads from committing > --- > > Key: OAK-8071 > URL: https://issues.apache.org/jira/browse/OAK-8071 > Project: Jackrabbit Oak > Issue Type: Technical task > Components: segment-tar >Reporter: Michael Dürig >Assignee: Michael Dürig >Priority: Blocker > Fix For: 1.12, 1.11.0, 1.8.12, 1.10.2 > > > Add logging / monitoring to detect the situation from OAK-8014. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
[ https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16779385#comment-16779385 ] Axel Hanikel commented on OAK-8071: --- [~mduerig] Sorry for the delay, I had to deal with some upgrade-related issues. The patch looks good to me. > Logging to detect commits carrying over from previous GC generation can block > other threads from committing > --- > > Key: OAK-8071 > URL: https://issues.apache.org/jira/browse/OAK-8071 > Project: Jackrabbit Oak > Issue Type: Technical task > Components: segment-tar >Reporter: Michael Dürig >Assignee: Michael Dürig >Priority: Blocker > Fix For: 1.12, 1.11.0, 1.8.12, 1.10.2 > > > Add logging / monitoring to detect the situation from OAK-8014. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
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]
Michael Dürig commented on OAK-8071:
[~ahanikel], could you have a look at this one:
[https://github.com/mduerig/jackrabbit-oak/commits/OAK-8071-logging]
this should be simple enough and low risk to backport.
There is an issue though with the way we detect the current commit crossing the
gc boundary (with this branch as well as with the JMX variant): at the point in
time where {{Commit#gcGeneration}} is set to a non {{null}} value, the
potentially time consuming rewriting has already taken place. However, it is
this rewriting that we want to detect in the first place. Currently the only
simple enough approach I'm seeing is to generally rely on the time it takes for
a commit to complete.
> Logging to detect commits carrying over from previous GC generation can block
> other threads from committing
> ---
>
> Key: OAK-8071
> URL: https://issues.apache.org/jira/browse/OAK-8071
> Project: Jackrabbit Oak
> Issue Type: Technical task
> Components: segment-tar
>Reporter: Michael Dürig
>Assignee: Michael Dürig
>Priority: Blocker
> Fix For: 1.12, 1.11.0, 1.8.12, 1.10.2
>
>
> Add logging / monitoring to detect the situation from OAK-8014.
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[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
[ https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16777917#comment-16777917 ] Axel Hanikel commented on OAK-8071: --- [~mduerig] I agree with what you say about the gc generation. For the CommitTracker, perhaps we can add a comment like [https://github.com/ahanikel/jackrabbit-oak/commits/OAK-8071-2] to make clear that the CommitTracker's dequeue and execute methods must now be used in sequence within the same critical section? > Logging to detect commits carrying over from previous GC generation can block > other threads from committing > --- > > Key: OAK-8071 > URL: https://issues.apache.org/jira/browse/OAK-8071 > Project: Jackrabbit Oak > Issue Type: Technical task > Components: segment-tar >Reporter: Michael Dürig >Assignee: Michael Dürig >Priority: Blocker > Fix For: 1.12, 1.11.0, 1.8.12, 1.10.2 > > > Add logging / monitoring to detect the situation from OAK-8014. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
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]
Michael Dürig commented on OAK-8071:
{quote}perhaps we can add a comment like
{quote}
Good point, I'll merge this into my branch.
OTOH, I while the new monitoring is quite sophisticated this way, I figured out
that I cannot backport it to 1.8. There are zillions of conflicts. I'm
currently trying an alternative and simpler approach logging warnings instead.
The JMX approach is still useful though for trunk I think. Will share another
branch soon.
> Logging to detect commits carrying over from previous GC generation can block
> other threads from committing
> ---
>
> Key: OAK-8071
> URL: https://issues.apache.org/jira/browse/OAK-8071
> Project: Jackrabbit Oak
> Issue Type: Technical task
> Components: segment-tar
>Reporter: Michael Dürig
>Assignee: Michael Dürig
>Priority: Blocker
> Fix For: 1.12, 1.11.0, 1.8.12, 1.10.2
>
>
> Add logging / monitoring to detect the situation from OAK-8014.
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[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
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]
Michael Dürig commented on OAK-8071:
Thanks [~ahanikel] for the feedback. I applied it with some modifications. Most
prominently I avoided to resolve the gc generation from JMX calls as this could
cause loading of segments. Instead I memoise the gc generation in
{{Commit#gcGeneration}} setting its value when the underlying segment needs to
be loaded anyway. I think this approach is especially important wrt.
{{SegmentNodeStoreStatsMBean#getQueuedWriters}}, which request the GC
generation of as many commits as are currently waiting. This means that for
queued commits the gc generation will usually show as N/A. I don't consider
this a problem as only the gc generation of the current commit in progress is
interesting for determining whether the current commit crossed a gc boundary
and might thus be susceptible for OAK-8014.
I cleaned up the commit history and grouped related changes in separate
commits. Please have a look at
https://github.com/mduerig/jackrabbit-oak/commits/OAK-8071-2
> Logging to detect commits carrying over from previous GC generation can block
> other threads from committing
> ---
>
> Key: OAK-8071
> URL: https://issues.apache.org/jira/browse/OAK-8071
> Project: Jackrabbit Oak
> Issue Type: Technical task
> Components: segment-tar
>Reporter: Michael Dürig
>Assignee: Michael Dürig
>Priority: Blocker
> Fix For: 1.12, 1.11.0, 1.8.12, 1.10.2
>
>
> Add logging / monitoring to detect the situation from OAK-8014.
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[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
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]
Axel Hanikel commented on OAK-8071:
---
[~mduerig] I've made a few changes in
[https://github.com/ahanikel/jackrabbit-oak/commits/OAK-8071] :
* Cosmetic change: Renamed variable "w" to "k" because I couldn't figure out
what "w" stands for ;)
* I think {{currentCommit}} should be volatile because it is probably called
from a different thread via {{#getCurrentWriter}} (although it's probably not a
big issue).
* I've tried to add the full GC generation to the {{CommitsTracker}} (but it's
not reflected in the {{SegmentNodeStoreStats}} yet). Perhaps you can quickly
check if what I did makes any sense...
Next steps:
* Add the generation to the {{SegmentNodeStoreStats}}.
* The {{CommitsTrackerTest}} (both tests) are failing for me. I'm going to
figure out why.
> Logging to detect commits carrying over from previous GC generation can block
> other threads from committing
> ---
>
> Key: OAK-8071
> URL: https://issues.apache.org/jira/browse/OAK-8071
> Project: Jackrabbit Oak
> Issue Type: Technical task
> Components: segment-tar
>Reporter: Michael Dürig
>Assignee: Michael Dürig
>Priority: Blocker
> Fix For: 1.12, 1.11.0, 1.8.12, 1.10.2
>
>
> Add logging / monitoring to detect the situation from OAK-8014.
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[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
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]
Michael Dürig commented on OAK-8071:
[~ahanikel], if you could also have a look at this one. Branch is here:
[https://github.com/mduerig/jackrabbit-oak/commits/OAK-8071] [~dulceanu] has
all the context re. {{LockBasedScheduler}} and the existing monitoring around
it.
> Logging to detect commits carrying over from previous GC generation can block
> other threads from committing
> ---
>
> Key: OAK-8071
> URL: https://issues.apache.org/jira/browse/OAK-8071
> Project: Jackrabbit Oak
> Issue Type: Technical task
> Components: segment-tar
>Reporter: Michael Dürig
>Assignee: Michael Dürig
>Priority: Blocker
> Fix For: 1.12, 1.11.0, 1.8.12, 1.10.2
>
>
> Add logging / monitoring to detect the situation from OAK-8014.
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[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
[ https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16775011#comment-16775011 ] Michael Dürig commented on OAK-8071: At [https://github.com/mduerig/jackrabbit-oak/commit/b1693aac12a863159db36f2b1eba4e5260796d95] I added support for * exposing time queued, dequeued and applied time stamps per commit currently waiting to commit * exposing the same for the commit currently in progress. [~dulceanu], let me know what you think once you got a min. > Logging to detect commits carrying over from previous GC generation can block > other threads from committing > --- > > Key: OAK-8071 > URL: https://issues.apache.org/jira/browse/OAK-8071 > Project: Jackrabbit Oak > Issue Type: Technical task > Components: segment-tar >Reporter: Michael Dürig >Assignee: Michael Dürig >Priority: Blocker > Fix For: 1.12, 1.11.0, 1.10.1, 1.8.12 > > > Add logging / monitoring to detect the situation from OAK-8014. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
[ https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16775013#comment-16775013 ] Michael Dürig commented on OAK-8071: One missing bit I still would like to add is the garbage collection generation a commit belongs to. This would be helpful to determine whether the commit crosses a gc boundary and would thus be susceptible of OAK-8014 > Logging to detect commits carrying over from previous GC generation can block > other threads from committing > --- > > Key: OAK-8071 > URL: https://issues.apache.org/jira/browse/OAK-8071 > Project: Jackrabbit Oak > Issue Type: Technical task > Components: segment-tar >Reporter: Michael Dürig >Assignee: Michael Dürig >Priority: Blocker > Fix For: 1.12, 1.11.0, 1.10.1, 1.8.12 > > > Add logging / monitoring to detect the situation from OAK-8014. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
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Michael Dürig commented on OAK-8071:
Thanks for reviewing.
{quote}it didn't seem a problem to miss a few events
{quote}
Ack, that's what I though. I think we need to change this assumption for this
issue so we don't risk missing a commit that might still end up being queued
for a long time.
> Logging to detect commits carrying over from previous GC generation can block
> other threads from committing
> ---
>
> Key: OAK-8071
> URL: https://issues.apache.org/jira/browse/OAK-8071
> Project: Jackrabbit Oak
> Issue Type: Technical task
> Components: segment-tar
>Reporter: Michael Dürig
>Assignee: Michael Dürig
>Priority: Blocker
> Fix For: 1.12, 1.11.0, 1.10.1, 1.8.12
>
>
> Add logging / monitoring to detect the situation from OAK-8014.
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[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
[ https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16774967#comment-16774967 ] Andrei Dulceanu commented on OAK-8071: -- [~mduerig], the changes in both commits LGTM. Regarding our previous discussion about the race condition, I got your point. At the time the code was written, it didn't seem a problem to miss a few events like this, as the functionality was considered rather an approximation anyways. > Logging to detect commits carrying over from previous GC generation can block > other threads from committing > --- > > Key: OAK-8071 > URL: https://issues.apache.org/jira/browse/OAK-8071 > Project: Jackrabbit Oak > Issue Type: Technical task > Components: segment-tar >Reporter: Michael Dürig >Assignee: Michael Dürig >Priority: Blocker > Fix For: 1.12, 1.11.0, 1.10.1, 1.8.12 > > > Add logging / monitoring to detect the situation from OAK-8014. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
[ https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16774913#comment-16774913 ] Michael Dürig commented on OAK-8071: [~dulceanu], in summary: performance is not an issue as with the [second commit|https://github.com/mduerig/jackrabbit-oak/commit/0dd87632ae6ec2228ac35fcdc8e919982559fb16] stack trace collection will not be eager any more. The performance regression only shows up when looking at the [first commit|https://github.com/mduerig/jackrabbit-oak/commit/fcc2c85182d16e4838645e3a35c43d358c687421] in isolation. Would be great if you could have another look and double check whether I missed something. > Logging to detect commits carrying over from previous GC generation can block > other threads from committing > --- > > Key: OAK-8071 > URL: https://issues.apache.org/jira/browse/OAK-8071 > Project: Jackrabbit Oak > Issue Type: Technical task > Components: segment-tar >Reporter: Michael Dürig >Assignee: Michael Dürig >Priority: Blocker > Fix For: 1.12, 1.11.0, 1.10.1, 1.8.12 > > > Add logging / monitoring to detect the situation from OAK-8014. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
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]
Michael Dürig commented on OAK-8071:
Just noted though that removing this check causes a lot of additional commits
to end up on the {{CommitsTracker#commits}} queue. This causes a performance
regression in our benchmarks:
{noformat}
Apache Jackrabbit Oak
# FlatTreeUpdateTest C min 10% 50% 90% max
N
Oak-Segment-Tar (base) 1 5593 5600 5938 6302 6321
11
Oak-Segment-Tar (OAK-8071) 1 6849 6849 7076 8821 8821
9
{noformat}
Will have to look for another solution.
> Logging to detect commits carrying over from previous GC generation can block
> other threads from committing
> ---
>
> Key: OAK-8071
> URL: https://issues.apache.org/jira/browse/OAK-8071
> Project: Jackrabbit Oak
> Issue Type: Technical task
> Components: segment-tar
>Reporter: Michael Dürig
>Assignee: Michael Dürig
>Priority: Blocker
> Fix For: 1.12, 1.11.0, 1.10.1, 1.8.12
>
>
> Add logging / monitoring to detect the situation from OAK-8014.
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[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
[ https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16774888#comment-16774888 ] Michael Dürig commented on OAK-8071: My concern is about missing a thread that might get queued: when a permit is available when checking but then later the lock is already taken by another thread. In this case the thread waiting for the lock will not be marked as queued. When we remove this extra check all threads will go through this virtual queue. Just that most threads will get unqueued quickly again. > Logging to detect commits carrying over from previous GC generation can block > other threads from committing > --- > > Key: OAK-8071 > URL: https://issues.apache.org/jira/browse/OAK-8071 > Project: Jackrabbit Oak > Issue Type: Technical task > Components: segment-tar >Reporter: Michael Dürig >Assignee: Michael Dürig >Priority: Blocker > Fix For: 1.12, 1.11.0, 1.10.1, 1.8.12 > > > Add logging / monitoring to detect the situation from OAK-8014. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
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Andrei Dulceanu commented on OAK-8071:
--
{quote}Do you remember why this check for the number of available permits was
put in place?
{quote}
AFAICR, this was the only method for determining if a certain commit will be
executed right away or will be queued, because the semaphore was already
acquired.
Regarding your concern about a race condition, I'm not sure how this could
happen. IMO, the worst thing that could happen is that a thread which initially
sees that no permits are available is marked as queued, even though the thread
which acquired the semaphore released it in the mean time (after the if check).
Following this point, only one thread will be able to execute commits (having
already acquired the semaphore).
[~mduerig], WDYT about the reasoning above?
> Logging to detect commits carrying over from previous GC generation can block
> other threads from committing
> ---
>
> Key: OAK-8071
> URL: https://issues.apache.org/jira/browse/OAK-8071
> Project: Jackrabbit Oak
> Issue Type: Technical task
> Components: segment-tar
>Reporter: Michael Dürig
>Assignee: Michael Dürig
>Priority: Blocker
> Fix For: 1.12, 1.11.0, 1.10.1, 1.8.12
>
>
> Add logging / monitoring to detect the situation from OAK-8014.
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[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
[ https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16774494#comment-16774494 ] Michael Dürig commented on OAK-8071: At [https://github.com/mduerig/jackrabbit-oak/commit/0dd87632ae6ec2228ac35fcdc8e919982559fb16] I added a timestamp to the monitoring of the queued commits. At the same time I refactored the handling of processing the stack traces a bit deferring their evaluation to the point where they are requested. [~dulceanu], could you have a look? > Logging to detect commits carrying over from previous GC generation can block > other threads from committing > --- > > Key: OAK-8071 > URL: https://issues.apache.org/jira/browse/OAK-8071 > Project: Jackrabbit Oak > Issue Type: Technical task > Components: segment-tar >Reporter: Michael Dürig >Assignee: Michael Dürig >Priority: Blocker > Fix For: 1.12, 1.11.0, 1.10.1, 1.8.12 > > > Add logging / monitoring to detect the situation from OAK-8014. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-8071) Logging to detect commits carrying over from previous GC generation can block other threads from committing
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https://issues.apache.org/jira/browse/OAK-8071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16774229#comment-16774229
]
Michael Dürig commented on OAK-8071:
As prerequisite I propose to remove a potential race condition in the
monitoring of the {{LockBasedScheduler}}: Always handle commits as queued even
when the lock is free to avoid races between checking the number of available
permits and actually acquiring the lock. [~dulceanu], do you remember why this
check for the number of available permits was put in place?
See
[https://github.com/mduerig/jackrabbit-oak/commit/fcc2c85182d16e4838645e3a35c43d358c687421]
> Logging to detect commits carrying over from previous GC generation can block
> other threads from committing
> ---
>
> Key: OAK-8071
> URL: https://issues.apache.org/jira/browse/OAK-8071
> Project: Jackrabbit Oak
> Issue Type: Technical task
> Components: segment-tar
>Reporter: Michael Dürig
>Assignee: Michael Dürig
>Priority: Blocker
> Fix For: 1.12, 1.11.0, 1.10.1, 1.8.12
>
>
> Add logging / monitoring to detect the situation from OAK-8014.
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