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Posted to dev@ignite.apache.org by Maxim Muzafarov <ma...@gmail.com> on 2018/09/28 13:05:46 UTC
[QUESTION] SegmentAware holder initialization (fix of WAL blocked rollOver)
Igniters,
I would like to discuss this question here and create a separate topic for
it. Previously, I've posted some comments on the probable issue in Apache
Ignite 2.7 topic [2]. My question is related to the IGNITE-8559 [3] (commit
[4]). We've added a new SegmentAware class and change the
FileWriteAheadLogManager behaviour.
The FileWriteAheadLogManager now contains:
`private final SegmentAware segmentAware;`.
The SegmentAware have the `interrupt()` method which at manager
de-activation sets (e.g. for SegmentArchivedStorage) `interrupted` filed to
`true` value [5] but never revert it to `false` after activation. So, the
SegmentArchivedStorage after de-activation always remain interrupted.
I think it can lead us to unpredictable issues with multiple cluster
activation/de-activation. I don't know why all tests in master branch
suppose to be successful but in my local branch, they hang on exchange
future get() method.
My local solution (probably not ideal) is:
1) make it volatile - `private volatile SegmentAware segmentAware;`
2) move field init to the `start0()` method of FileWriteAheadLogManager;
With these changes, everything begins to work fine but I can miss something
because I don’t understand the whole this change well enough.
Can anyone comment on this and share details IGNITE-8559 implementation?
[1]
https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/persistence/wal/FileWriteAheadLogManager.java#L319
[2]
http://apache-ignite-developers.2346864.n4.nabble.com/Apache-Ignite-2-7-release-tp34076p35863.html
[3] https://issues.apache.org/jira/browse/IGNITE-8559
[4]
https://github.com/apache/ignite/commit/2f72fe758d4256c4eb4610e5922ad3d174b43dc5
[5]
https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/persistence/wal/aware/SegmentArchivedStorage.java#L117
--
--
Maxim Muzafarov
Re: [QUESTION] SegmentAware holder initialization (fix of WAL blocked rollOver)
Posted by Maxim Muzafarov <ma...@gmail.com>.
Anton,
Thank you for your reply and clarification.
I've created a ticket [1] for this fix. Can you take it, please?
Probably, I have the solution for the issue described above and at the
first the glance it looks not too bad.
But I can't guarantee the completeness of my fix and the fact that I took
all the details into account. As an
author of the IGNITE-8559 commit, you definitely know all details better
rather than me.
I've marked the issue to be included in the 2.7 release, but it also
discussable.
[1] https://issues.apache.org/jira/browse/IGNITE-9741
On Fri, 28 Sep 2018 at 19:53 Anton Kalashnikov <ka...@yandex.ru> wrote:
> Hello.
>
> Looks like you are right about interrupted flag. I don't understand why
> tests was pass successfully in master. Your solution also looks correct.
>
> SegmentAware - it's info object of actual state of WAL segments like
> "current work segment", "last archived segment" etc. Actually it's nothing
> new here. It just was extracted from FileWriteAheadLogManager for
> centralization and future simplification. It should not change a old
> behaviour if it was happened it will need to be investigate.
>
> If you already have fix for it, please will create task and add me to the
> watchers. Or I can fix it by myself.
>
> --
> Best regards,
> Anton Kalashnikov
>
>
> 28.09.2018, 16:06, "Maxim Muzafarov" <ma...@gmail.com>:
> > Igniters,
> >
> > I would like to discuss this question here and create a separate topic
> for
> > it. Previously, I've posted some comments on the probable issue in Apache
> > Ignite 2.7 topic [2]. My question is related to the IGNITE-8559 [3]
> (commit
> > [4]). We've added a new SegmentAware class and change the
> > FileWriteAheadLogManager behaviour.
> >
> > The FileWriteAheadLogManager now contains:
> >
> > `private final SegmentAware segmentAware;`.
> >
> > The SegmentAware have the `interrupt()` method which at manager
> > de-activation sets (e.g. for SegmentArchivedStorage) `interrupted` filed
> to
> > `true` value [5] but never revert it to `false` after activation. So, the
> > SegmentArchivedStorage after de-activation always remain interrupted.
> >
> > I think it can lead us to unpredictable issues with multiple cluster
> > activation/de-activation. I don't know why all tests in master branch
> > suppose to be successful but in my local branch, they hang on exchange
> > future get() method.
> >
> > My local solution (probably not ideal) is:
> > 1) make it volatile - `private volatile SegmentAware segmentAware;`
> > 2) move field init to the `start0()` method of FileWriteAheadLogManager;
> >
> > With these changes, everything begins to work fine but I can miss
> something
> > because I don’t understand the whole this change well enough.
> >
> > Can anyone comment on this and share details IGNITE-8559 implementation?
> >
> > [1]
> >
> https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/persistence/wal/FileWriteAheadLogManager.java#L319
> > [2]
> >
> http://apache-ignite-developers.2346864.n4.nabble.com/Apache-Ignite-2-7-release-tp34076p35863.html
> > [3] https://issues.apache.org/jira/browse/IGNITE-8559
> > [4]
> >
> https://github.com/apache/ignite/commit/2f72fe758d4256c4eb4610e5922ad3d174b43dc5
> > [5]
> >
> https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/persistence/wal/aware/SegmentArchivedStorage.java#L117
> > --
> > --
> > Maxim Muzafarov
>
--
--
Maxim Muzafarov
Re: [QUESTION] SegmentAware holder initialization (fix of WAL blocked rollOver)
Posted by Anton Kalashnikov <ka...@yandex.ru>.
Hello.
Looks like you are right about interrupted flag. I don't understand why tests was pass successfully in master. Your solution also looks correct.
SegmentAware - it's info object of actual state of WAL segments like "current work segment", "last archived segment" etc. Actually it's nothing new here. It just was extracted from FileWriteAheadLogManager for centralization and future simplification. It should not change a old behaviour if it was happened it will need to be investigate.
If you already have fix for it, please will create task and add me to the watchers. Or I can fix it by myself.
--
Best regards,
Anton Kalashnikov
28.09.2018, 16:06, "Maxim Muzafarov" <ma...@gmail.com>:
> Igniters,
>
> I would like to discuss this question here and create a separate topic for
> it. Previously, I've posted some comments on the probable issue in Apache
> Ignite 2.7 topic [2]. My question is related to the IGNITE-8559 [3] (commit
> [4]). We've added a new SegmentAware class and change the
> FileWriteAheadLogManager behaviour.
>
> The FileWriteAheadLogManager now contains:
>
> `private final SegmentAware segmentAware;`.
>
> The SegmentAware have the `interrupt()` method which at manager
> de-activation sets (e.g. for SegmentArchivedStorage) `interrupted` filed to
> `true` value [5] but never revert it to `false` after activation. So, the
> SegmentArchivedStorage after de-activation always remain interrupted.
>
> I think it can lead us to unpredictable issues with multiple cluster
> activation/de-activation. I don't know why all tests in master branch
> suppose to be successful but in my local branch, they hang on exchange
> future get() method.
>
> My local solution (probably not ideal) is:
> 1) make it volatile - `private volatile SegmentAware segmentAware;`
> 2) move field init to the `start0()` method of FileWriteAheadLogManager;
>
> With these changes, everything begins to work fine but I can miss something
> because I don’t understand the whole this change well enough.
>
> Can anyone comment on this and share details IGNITE-8559 implementation?
>
> [1]
> https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/persistence/wal/FileWriteAheadLogManager.java#L319
> [2]
> http://apache-ignite-developers.2346864.n4.nabble.com/Apache-Ignite-2-7-release-tp34076p35863.html
> [3] https://issues.apache.org/jira/browse/IGNITE-8559
> [4]
> https://github.com/apache/ignite/commit/2f72fe758d4256c4eb4610e5922ad3d174b43dc5
> [5]
> https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/persistence/wal/aware/SegmentArchivedStorage.java#L117
> --
> --
> Maxim Muzafarov