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Posted to commits@cassandra.apache.org by "Andres de la Peña (Jira)" <ji...@apache.org> on 2020/12/01 00:39:00 UTC

[jira] [Updated] (CASSANDRA-16307) GROUP BY queries with paging can return deleted data

     [ https://issues.apache.org/jira/browse/CASSANDRA-16307?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andres de la Peña updated CASSANDRA-16307:
------------------------------------------
    Since Version: 3.10

> GROUP BY queries with paging can return deleted data
> ----------------------------------------------------
>
>                 Key: CASSANDRA-16307
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-16307
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Consistency/Coordination
>            Reporter: Andres de la Peña
>            Priority: Normal
>
> {{GROUP BY}} queries using paging and CL>ONE/LOCAL_ONE. This dtest reproduces the problem:
> {code:java}
> try (Cluster cluster = init(Cluster.create(2)))
> {
>     cluster.schemaChange(withKeyspace("CREATE TABLE %s.t (pk int, ck int, PRIMARY KEY (pk, ck))"));
>     ICoordinator coordinator = cluster.coordinator(1);
>     coordinator.execute(withKeyspace("INSERT INTO %s.t (pk, ck) VALUES (0, 0)"), ConsistencyLevel.ALL);
>     coordinator.execute(withKeyspace("INSERT INTO %s.t (pk, ck) VALUES (1, 1)"), ConsistencyLevel.ALL);
>     
>     cluster.get(1).executeInternal(withKeyspace("DELETE FROM %s.t WHERE pk=0 AND ck=0"));
>     cluster.get(2).executeInternal(withKeyspace("DELETE FROM %s.t WHERE pk=1 AND ck=1"));
>     String query = withKeyspace("SELECT * FROM %s.t GROUP BY pk");
>     Iterator<Object[]> rows = coordinator.executeWithPaging(query, ConsistencyLevel.ALL, 1);
>     assertRows(Iterators.toArray(rows, Object[].class));
> }
> {code}
> Using a 2-node cluster and RF=2, the test inserts two partitions in both nodes. Then it locally deletes each row in a separate node, so each node sees a different partition alive, but reconciliation should produce no alive partitions. However, a {{GROUP BY}} query using a page size of 1 wrongly returns one of the rows.
> This has been detected during CASSANDRA-16180, and it is probably related to CASSANDRA-15459, which solved a similar problem for group-by queries with limit, instead of paging.



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