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Daniel Becker updated IMPALA-11418: ----------------------------------- Fix Version/s: (was: Impala 4.2.0) Target Version: Impala 4.3.0 > Optimize select contant statement min memory reservation > -------------------------------------------------------- > > Key: IMPALA-11418 > URL: https://issues.apache.org/jira/browse/IMPALA-11418 > Project: IMPALA > Issue Type: Improvement > Components: Frontend > Affects Versions: Impala 4.0.0, Impala 4.1.0 > Reporter: Xianqing He > Assignee: Xianqing He > Priority: Major > > If SPOOL_QUERY_RESULTS is true, then the ResourceProfile sets a min > reservation in PlanRootSink. > For the statement 'select 1', the min reservation is 4MB. It's no problem if > the cluster has enough mem available within its process limit to execute the > query. But if the host mem not available it will throw 'Failed to get minimum > memory reservation'. > Some connection pools use 'select 1' to check whether the connection is > available. The check will fail if memory is oversubscribed. > For this case we can set the min reservation to 0 to reduce failure when the > memory is oversubscribed. > > {code:java} > Query: explain select 1 > +--------------------------------------------------------+ > | Explain String | > +--------------------------------------------------------+ > | Max Per-Host Resource Reservation: Memory=4MB Threads=1 | > | Per-Host Resource Estimates: Memory=10MB | > | Codegen disabled by planner | > | | > | PLAN-ROOT SINK | > | | | > | 00:UNION | > | constant-operands=1 | > | row-size=1B cardinality=1 | > +--------------------------------------------------------+ {code} > -- This message was sent by Atlassian Jira (v8.20.10#820010) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-all-unsubscr...@impala.apache.org For additional commands, e-mail: issues-all-h...@impala.apache.org