[jira] [Commented] (CASSANDRA-12212) system.compactions_in_progress needs to be used on first upgrade to 3.0

["Stefania (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-12212?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15381613#comment-15381613 ] 

Stefania commented on CASSANDRA-12212:
--------------------------------------

Was there an actual problem caused by this? We delete unfinished temporary files in {{SystemKeyspace.migrateDataDirs()}}.

As for final files, consulting {{system.compactions_in_progress}} would only partially help because the old files still exist when the entry in the table is deleted by {{CompactionTask.runMyThrow()}}. There is a time interval between temporary new files being promoted to final new files and the deletion of the entry in the table, this would be protected, but the time interval between the deletion of the entry and the deletion of old files (which could be much longer if other references to the sstables exist) is not protected. As far as it was understood during the development of 7066, the only adverse effect of this is a redundant compaction since counters no longer double-count in 2.1.

Further, since CASSANDRA-10079 we also cancel compactions in progress in nodetool drain, so if people follow the upgrade procedure there won't be any entry in the table or left-overs on disk.

> system.compactions_in_progress needs to be used on first upgrade to 3.0
> -----------------------------------------------------------------------
>
>                 Key: CASSANDRA-12212
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-12212
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Compaction
>            Reporter: Jeremiah Jordan
>            Assignee: Stefania
>             Fix For: 3.0.x, 3.x
>
>
> CASSANDRA-7066 removed the system.compactions_in_progress table and replaced it with the new transaction system.  But system.compactions_in_progress needs to be consulted for the first startup after upgrading from 2.1 to 3.0.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)