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Posted to commits@cassandra.apache.org by "Jonathan Ellis (JIRA)" <ji...@apache.org> on 2016/07/22 12:52:20 UTC
[jira] [Commented] (CASSANDRA-11223) Queries with LIMIT filtering
on clustering columns can return less row than expected
[ https://issues.apache.org/jira/browse/CASSANDRA-11223?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15389437#comment-15389437 ]
Jonathan Ellis commented on CASSANDRA-11223:
--------------------------------------------
Is this obsoleted then by [~stefania_alborghetti]'s work on CASSANDRA-11521?
> Queries with LIMIT filtering on clustering columns can return less row than expected
> ------------------------------------------------------------------------------------
>
> Key: CASSANDRA-11223
> URL: https://issues.apache.org/jira/browse/CASSANDRA-11223
> Project: Cassandra
> Issue Type: Bug
> Components: Local Write-Read Paths
> Reporter: Benjamin Lerer
> Assignee: Benjamin Lerer
>
> A query like {{SELECT * FROM %s WHERE b = 1 LIMIT 2 ALLOW FILTERING}} can return less row than expected if the table has some static columns and some of the partition have no rows matching b = 1.
> The problem can be reproduced with the following unit test:
> {code}
> public void testFilteringOnClusteringColumnsWithLimitAndStaticColumns() throws Throwable
> {
> createTable("CREATE TABLE %s (a int, b int, s int static, c int, primary key (a, b))");
> for (int i = 0; i < 3; i++)
> {
> execute("INSERT INTO %s (a, s) VALUES (?, ?)", i, i);
> for (int j = 0; j < 3; j++)
> if (!(i == 0 && j == 1))
> execute("INSERT INTO %s (a, b, c) VALUES (?, ?, ?)", i, j, i + j);
> }
> assertRows(execute("SELECT * FROM %s"),
> row(1, 0, 1, 1),
> row(1, 1, 1, 2),
> row(1, 2, 1, 3),
> row(0, 0, 0, 0),
> row(0, 2, 0, 2),
> row(2, 0, 2, 2),
> row(2, 1, 2, 3),
> row(2, 2, 2, 4));
> assertRows(execute("SELECT * FROM %s WHERE b = 1 ALLOW FILTERING"),
> row(1, 1, 1, 2),
> row(2, 1, 2, 3));
> assertRows(execute("SELECT * FROM %s WHERE b = 1 LIMIT 2 ALLOW FILTERING"),
> row(1, 1, 1, 2),
> row(2, 1, 2, 3)); // <-------- FAIL It returns only one row because the static row of partition 0 is counted and filtered out in SELECT statement
> }
> {code}
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