[jira] [Commented] (ARTEMIS-3868) Improve Journal Compactor split logic

["Clebert Suconic (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ARTEMIS-3868?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17559286#comment-17559286 ] 

Clebert Suconic commented on ARTEMIS-3868:
------------------------------------------

[~fabio.nb] I sent a PR: https://github.com/apache/activemq-artemis/pull/4124


and again.. I'm pretty sure the issue you faced was https://github.com/apache/activemq-artemis/pull/4124



> Improve Journal Compactor split logic
> -------------------------------------
>
>                 Key: ARTEMIS-3868
>                 URL: https://issues.apache.org/jira/browse/ARTEMIS-3868
>             Project: ActiveMQ Artemis
>          Issue Type: Improvement
>          Components: ActiveMQ-Artemis-Native
>    Affects Versions: 2.19.0, 2.20.0, 2.21.0, 2.22.0, 2.23.0, 2.23.1
>         Environment: I am marking this as an improvement, since the error condition shouldn't really happen in real life since compacted records will be written first.
> I'm accepting the improvement though.
>            Reporter: Fabio Nascimento Brandão
>            Assignee: Clebert Suconic
>            Priority: Major
>             Fix For: 2.24.0
>
>         Attachments: CompactDiskUsage.java, image-2022-06-21-19-33-59-276.png
>
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> We are having some problems with disk space usage. Basically we have a lot of queues and one of them fail to consume the messages (problem in a microservice for about 10 minutes).
> Then we use the message redelivery feature to process these messages again after some delay.
> The problems ocurrs with de journal compact. This process creates a lot of files until fill the disk.
> I took some created files at production server and tried to compact them. The disk usage grow a lot and only after the second compact process the disk usage stayed at an acceptable level.
> I attached a "test" to reproduce the problem. The test create one journal file with 2048 records and using only 2,1MB. The records have an information that is the "compact count". I adjusted this field to 1 and 2.
> What I found out is when the compactor process a record with this field less than 2 (after some record being greater or equals to 2), the JournalCompactor creates a new file.
> In this test, when I start the journal it creates a new file of 10MB (default configuration) and keeps the 2,1MB file.
> When I ran the compact process, It creates 1024 files and keeps the old 2. 1024 * 10MB = 10GB!!!
> If I ran the compact process again, It shrink to only 2 files of 10MB!!!
> The problem seems to be in the JournalCompactor at method checkCompact. I think we can remove this method and assume the flow like it returned false:
> [https://github.com/apache/activemq-artemis/blob/main/artemis-journal/src/main/java/org/apache/activemq/artemis/core/journal/impl/JournalCompactor.java#L190-L203]
> This was an old code that was introduced at HornetQ:
> [https://github.com/hornetq/hornetq/commit/93af1cb92f4050e54e83c8daa9c67ce43dbcfead]
> I also attached an image with the disk usage of my production server with the problem.



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