[
https://issues.apache.org/jira/browse/CASSANDRA-3952?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13223082#comment-13223082
]
Peter Schuller commented on CASSANDRA-3952:
-------------------------------------------
I think this might happen whenever there is exactly one sstable in L0 that is
large enough for the score for L0 to be > 1, *and* if L1 is full (so that
skipLevels doesn't promote).
It's possible the sstables I had lying around from sized-tiered compaction
combined with my write load conspired to trigger this case.
I'll go over the patch once again and try to be sure we are never accidentally
not adding the level information somewhere. If it looks good I'll file this
problem in a separate ticket.
> avoid quadratic startup time in LeveledManifest
> -----------------------------------------------
>
> Key: CASSANDRA-3952
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3952
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Jonathan Ellis
> Assignee: Dave Brosius
> Priority: Minor
> Labels: lhf
> Fix For: 1.1.1
>
> Attachments: speed_up_level_of.diff
>
>
> Checking that each sstable is in the manifest on startup is O(N**2) in the
> number of sstables:
> {code}
> . // ensure all SSTables are in the manifest
> for (SSTableReader ssTableReader : cfs.getSSTables())
> {
> if (manifest.levelOf(ssTableReader) < 0)
> manifest.add(ssTableReader);
> }
> {code}
> {code}
> private int levelOf(SSTableReader sstable)
> {
> for (int level = 0; level < generations.length; level++)
> {
> if (generations[level].contains(sstable))
> return level;
> }
> return -1;
> }
> {code}
> Note that the contains call is a linear List.contains.
> We need to switch to a sorted list and bsearch, or a tree, to support
> TB-levels of data in LeveledCompactionStrategy.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
