[
https://issues.apache.org/jira/browse/CASSANDRA-20829?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18013699#comment-18013699
]
Branimir Lambov commented on CASSANDRA-20829:
---------------------------------------------
There's nothing wrong with that, but it needs to be in addition to a change to
explicitly go through the expired sstables. Going through the compaction path
is not just inefficient, but also not entirely correct (because of the problem
of retaining tombstones for various reasons).
Instead of going through the compaction path, we need to walk the expired
sstables as described above and call {{{}IndexGCTransaction{}}}'s methods
(perhaps I should have been more explicit on that above,
{{sendToIndexAsDeleted}} should be doing [the same thing the listener
would|https://github.com/apache/cassandra/blob/cassandra-4.1/src/java/org/apache/cassandra/db/compaction/CompactionIterator.java#L247]
for these rows).
> Secondary index implementations do not integrate with IndexGCTransaction when
> compaction contains fully expired SSTables
> ------------------------------------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-20829
> URL: https://issues.apache.org/jira/browse/CASSANDRA-20829
> Project: Apache Cassandra
> Issue Type: Bug
> Components: Feature/2i Index, Local/Compaction, Local/Compaction/TWCS
> Reporter: Stefan Miklosovic
> Assignee: Stefan Miklosovic
> Priority: Normal
> Fix For: 4.0.x, 4.1.x
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> There is a test (1) which ensures that when data are TTLed and compacted,
> IndexGCTransaction is aware of that and it will invoke Indexer.removeRow()
> method eventually.
> However, this is not working properly when we have fully expired SSTables,
> e.g. as the result of a table being on TWCS and having TTL on that.
> The reason is that in CompactionTask, we are filtering out fully expired ones
> (2). These then do not go to the compaction process and then they are not
> reacted on in listener() (3) which contains this logic (4). Eventually,
> onRowMerge in IndexGCTransaction will make the diff and in its commit
> indexer.removeRow(row); will notify 2i about its removal.
>
> This integration is missing and it is quite a big problem because if there
> are custom secondary index implementations the fact that SSTables were fully
> expired is not propagated to them which means that data are never removed
> from whatever backend they use.
> The solution is to go to the compaction with fully expired SSTables as well
> _but only if we detected that respective column family has some indexes_
>
> (1)
> [https://github.com/apache/cassandra/blob/cassandra-4.1/test/unit/org/apache/cassandra/index/CustomIndexTest.java#L583-L607]
> (2)
> [https://github.com/apache/cassandra/blob/cassandra-4.1/src/java/org/apache/cassandra/db/compaction/CompactionTask.java#L174]
> (3)
> [https://github.com/apache/cassandra/blob/cassandra-4.1/src/java/org/apache/cassandra/db/compaction/CompactionIterator.java#L130]
> (4)
> [https://github.com/apache/cassandra/blob/cassandra-4.1/src/java/org/apache/cassandra/db/compaction/CompactionIterator.java#L235-L252]
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org
For additional commands, e-mail: commits-h...@cassandra.apache.org
