Yuki Morishita created CASSANDRA-5907:
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Summary: Leveled compaction may cause overlap in L1 when L0
compaction get behind
Key: CASSANDRA-5907
URL: https://issues.apache.org/jira/browse/CASSANDRA-5907
Project: Cassandra
Issue Type: Bug
Reporter: Yuki Morishita
Assignee: Yuki Morishita
Priority: Minor
Fix For: 1.2.9
1.2 makes LCS run parallel, though if L0 compaction get far behind and
concurrent compactions at L0 where each compaction holds maximum number of
SSTable to compact at L0(32), it will likely cause overlap in L1. There will be
ERROR log as follows:
{code}
ERROR [CompactionExecutor:30] 2013-08-19 17:54:29,648 LeveledManifest.java
(line 244) At level 1, SSTableReader(path='xxx-Data.db')
[DecoratedKey(204853724659241194183955214890519, 30303132343830),
DecoratedKey(69227335985728660912035125310473966323, 30393537373332)] overlaps
SSTableReader(path='xxx-Data.db')
[DecoratedKey(217896711032704014921095870827202, 30333635363932),
DecoratedKey(71430242198281555888954138354238066233, 30333035343132)]. This is
caused by a bug in Cassandra 1.1.0 .. 1.1.3. Sending back to L0. If you have
not yet run scrub, you should do so since you may also have rows out-of-order
within an sstable
{code}
We should send back compacted SSTables to L0 when compacting max SSTables at
L0. Also, the above error message is confusing, at version 1.2, we can reduce
to WARNing level without mentioning scrub.
C* 2.0 performs Size-Tiered compaction on L0 when it has max SSTables and sends
back compacted SSTable to L0, so I think we don't need to fix this on 2.0.
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