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Dimitar Dimitrov commented on CASSANDRA-13801: ---------------------------------------------- It turns out that the problem does not necessarily require altering the compaction strategy. It seems to be rooted in a potential problem with counting the CF compaction requests, that can eventually lead to a skipped background compaction. The wrong counting can happen if the counting multiset increment [here|https://github.com/apache/cassandra/blob/95b43b195e4074533100f863344c182a118a8b6c/src/java/org/apache/cassandra/db/compaction/CompactionManager.java#L197] gets delayed and happens after the corresponding counting multiset decrement already happened [here|https://github.com/apache/cassandra/blob/95b43b195e4074533100f863344c182a118a8b6c/src/java/org/apache/cassandra/db/compaction/CompactionManager.java#L284]. Here are the branches with the proposed changes, as well as a Byteman test that can be used to demonstrate the issue. testall results look good (3.0 and trunk each have 1 seemingly unrelated, flaky test failing). dtest results will be added soon. | [2.2|https://github.com/apache/cassandra/compare/cassandra-2.2...dimitarndimitrov:c13801-2.2] | [testall|^c13801-2.2-testall.png] | | [3.0|https://github.com/apache/cassandra/compare/cassandra-3.0...dimitarndimitrov:c13801-3.0] | [testall|^c13801-3.0-testall.png] | | [3.11|https://github.com/apache/cassandra/compare/cassandra-3.11...dimitarndimitrov:c13801-3.11] | [testall|^c13801-3.11-testall.png] | | [trunk|https://github.com/apache/cassandra/compare/trunk...dimitarndimitrov:c13801-trunk] | [testall|^c13801-2.2-testall.png] | > CompactionManager sometimes wrongly determines that a background compaction > is running for a particular table > ------------------------------------------------------------------------------------------------------------- > > Key: CASSANDRA-13801 > URL: https://issues.apache.org/jira/browse/CASSANDRA-13801 > Project: Cassandra > Issue Type: Bug > Components: Compaction > Reporter: Dimitar Dimitrov > Assignee: Dimitar Dimitrov > Priority: Minor > > Sometimes after writing different rows to a table, then doing a blocking > flush, if you alter the compaction strategy, then run background compaction > and wait for it to finish, {{CompactionManager}} may decide that there's an > ongoing compaction for that same table. > This may happen even though logs don't indicate that to be the case > (compaction may still be running for system_schema tables). -- This message was sent by Atlassian JIRA (v6.4.14#64029) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org