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From "Tyler Hobbs (JIRA)" <j...@apache.org>
Subject [jira] [Created] (CASSANDRA-8239) NamesQueryFilters do not update SSTable read rate metrics
Date Fri, 31 Oct 2014 23:45:35 GMT
Tyler Hobbs created CASSANDRA-8239:
--------------------------------------

             Summary: NamesQueryFilters do not update SSTable read rate metrics
                 Key: CASSANDRA-8239
                 URL: https://issues.apache.org/jira/browse/CASSANDRA-8239
             Project: Cassandra
          Issue Type: Bug
          Components: Core
            Reporter: Tyler Hobbs
            Assignee: Tyler Hobbs
            Priority: Blocker
             Fix For: 2.1.2


In {{CollationController.collectionTimeOrderedData()}}, we are not calling {{sstable.incrementReadCount()}}.
 If a table is queried exclusively with these types of queries, its read meter will never
be updated.  Since SizeTieredCompactionStrategy depends on the read meter for omitting cold
sstables form compaction, this can result in no compactions being performed.  (I believe this
would require an occasional non-NamesQueryFilter query to happen, because if all of the readMeters
have a rate of 0.0, compaction will proceed normally.)  The IndexSummaryManager is also affected.

A workaround for compactions not occurring is to run the following:

{noformat}
ALTER TABLE <tablename> WITH compaction = {'class': 'SizeTieredCompactionStrategy',
'min_threshold': '4', 'max_threshold': '32', 'cold_reads_to_omit': 0.0};
{noformat}



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