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Posted to commits@cassandra.apache.org by "Sylvain Lebresne (JIRA)" <ji...@apache.org> on 2014/04/01 17:51:31 UTC
[jira] [Commented] (CASSANDRA-6825) COUNT(*) with WHERE not finding
all the matching rows
[ https://issues.apache.org/jira/browse/CASSANDRA-6825?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13956669#comment-13956669 ]
Sylvain Lebresne commented on CASSANDRA-6825:
---------------------------------------------
[~thobbs] Any insights on what it off in the logic exactly?
> COUNT(*) with WHERE not finding all the matching rows
> -----------------------------------------------------
>
> Key: CASSANDRA-6825
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6825
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Environment: quad core Windows7 x64, single node cluster
> Cassandra 2.0.5
> Reporter: Bill Mitchell
> Assignee: Tyler Hobbs
> Fix For: 2.0.7, 2.1 beta2
>
> Attachments: cassandra.log, selectpartitions.zip, selectrowcounts.txt, testdb_1395372407904.zip, testdb_1395372407904.zip
>
>
> Investigating another problem, I needed to do COUNT(*) on the several partitions of a table immediately after a test case ran, and I discovered that count(*) on the full table and on each of the partitions returned different counts.
> In particular case, SELECT COUNT(*) FROM sr LIMIT 1000000; returned the expected count from the test 99999 rows. The composite primary key splits the logical row into six distinct partitions, and when I issue a query asking for the total across all six partitions, the returned result is only 83999. Drilling down, I find that SELECT * from sr WHERE s = 5 AND l = 11 AND partition = 0; returns 30,000 rows, but a SELECT COUNT(*) with the identical WHERE predicate reports only 14,000.
> This is failing immediately after running a single small test, such that there are only two SSTables, sr-jb-1 and sr-jb-2. Compaction never needed to run.
> In selectrowcounts.txt is a copy of the cqlsh output showing the incorrect count(*) results.
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