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From "Sylvain Lebresne (JIRA)" <>
Subject [jira] [Created] (CASSANDRA-9478) SSTables are not always properly marked suspected
Date Tue, 26 May 2015 09:23:17 GMT
Sylvain Lebresne created CASSANDRA-9478:

             Summary: SSTables are not always properly marked suspected
                 Key: CASSANDRA-9478
             Project: Cassandra
          Issue Type: Bug
            Reporter: Sylvain Lebresne
            Assignee: Sylvain Lebresne

There is 2 problems:
# During compaction, {{SSTableIdentityIterator}} doesn't always mark sstables suspect (nor
always throws {{CorruptSSTableException}} in 2.0) This affects versions at least since 2.0
and up to trunk.
# Since 2.1, with CASSANDRA-916, {{SSTableReader.cloneWithNewStart}} doesn't preserve the
isSuspect flag. This a problem because when a {{CorruptSSTableException}} is thrown, the {{SSTableRewriter}}
is aborted, which replace {{SSTableReader}} by a clone of themselves and for the sstables
that have just been marked suspected this (wrongly) clears the flag.

The reason none of this has be caught so far is that the test that tests sstable blacklisting,
{{BlacklistingCompactionsTest}}, always corrupts the very beginning of sstables (the first
3 bytes). This conspire in hiding the 2 problems above because:
# the {{CorruptSSTableException}} is always thrown when we read the very first partition key,
which is actually properly covered in {{SSTableIdentityIterator}}.
# due to {{MergeIterator}} greediness, the exception is throw in {{CompactionTask.runMayThrow}}
on the creation of the iterator (on {{Iterator<AbstractCompactedRow> iter = ci.iterator()}}),
which is before the {{SSTableRewriter}} is even created, and so it's not aborted (and the
suspected flag is not cleared).
I've made some simple changes to {{BlacklistingCompactionsTest}} so it corrupts files a little
bit more randomly. At least on 2.1, the updated test pretty reliably find the 2 problems above.
On 2.2/trunk however, this doesn't find the 2nd one because since CASSANDRA-8568, {{SSTableRewriter.doAbort}}
do nothing if no early opening was actually perform, which will be the case in the test. We
would need a fancier test that ensure the corruption is far enough in the file that some early
opening has been done when it's thrown. But I don't have time for writing that test right
now so I'm gonna push that to a follow-up ticket.

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