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https://issues.apache.org/jira/browse/CASSANDRA-8938?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14487439#comment-14487439
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Anuj commented on CASSANDRA-8938:
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In our case we do some reporting using full table scans in off hours when
resources are free. We dont have an Analytics system like Spark. If sstables
are not compacted it affects reporting performance badly. So I think Cassandra
should be unbiased. If a data is read actively we will gain performance in
bothh workloads. Compaction will have cost and will impact transactional
resources temporarily but further Analytics hits would be much faster and those
hits will put less load on cassandra resources if tables are compacted.
> Full Row Scan does not count towards Reads
> ------------------------------------------
>
> Key: CASSANDRA-8938
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8938
> Project: Cassandra
> Issue Type: Bug
> Components: API, Core, Tools
> Environment: Unix, Cassandra 2.0.3
> Reporter: Amit Singh Chowdhery
> Assignee: Marcus Eriksson
> Priority: Minor
> Labels: none
>
> When a CQL SELECT statement is executed with WHERE clause, Read Count is
> incremented in cfstats of the column family. But, when a full row scan is
> done using SELECT statement without WHERE clause, Read Count is not
> incremented.
> Similarly, when using Size Tiered Compaction, if we do a full row scan using
> Hector RangeslicesQuery, Read Count is not incremented in cfstats, Cassandra
> still considers all sstables as cold and does not trigger compaction for
> them. If we fire MultigetSliceQuery, Read Count is incremented and sstables
> becomes hot, triggering compaction of these sstables.
> Expected Behavior:
> 1. Read Count must be incremented by number of rows read during a full row
> scan done using CQL SELECT statement or Hector RangeslicesQuery.
> 2. Size Tiered compaction must consider all sstables as Hot after a full row
> scan.
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