You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues-all@impala.apache.org by "Daniel Becker (Jira)" <ji...@apache.org> on 2022/11/23 12:19:00 UTC

[jira] [Updated] (IMPALA-11418) Optimize select contant statement min memory reservation

     [ https://issues.apache.org/jira/browse/IMPALA-11418?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

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-unsubscribe@impala.apache.org
For additional commands, e-mail: issues-all-help@impala.apache.org