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From "Krisztian Kasa (Jira)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-22163) CBO: Enabling CBO turns on stats estimation, even when the estimation is disabled
Date Mon, 16 Sep 2019 08:09:00 GMT

     [ https://issues.apache.org/jira/browse/HIVE-22163?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Krisztian Kasa updated HIVE-22163:
----------------------------------
    Status: Open  (was: Patch Available)

> CBO: Enabling CBO turns on stats estimation, even when the estimation is disabled
> ---------------------------------------------------------------------------------
>
>                 Key: HIVE-22163
>                 URL: https://issues.apache.org/jira/browse/HIVE-22163
>             Project: Hive
>          Issue Type: Bug
>          Components: CBO
>            Reporter: Gopal V
>            Assignee: Krisztian Kasa
>            Priority: Major
>         Attachments: HIVE-22163.1.patch, HIVE-22163.1.patch, HIVE-22163.1.patch, HIVE-22163.2.patch,
HIVE-22163.3.patch, HIVE-22163.4.patch, HIVE-22163.4.patch, HIVE-22163.5.patch, HIVE-22163.5.patch,
HIVE-22163.5.patch, HIVE-22163.5.patch
>
>
> {code}
> create table claims(claim_rec_id bigint, claim_invoice_num string, typ_c int);
> alter table claims update statistics set ('numRows'='1154941534','rawDataSize'='1135307527922');
> set hive.stats.estimate=false;
> explain extended select count(1) from claims where typ_c=3;
> set hive.stats.ndv.estimate.percent=5e-7;
> explain extended select count(1) from claims where typ_c=3;
> {code}
> Expecting the standard /2 for the single filter, but we instead get 5 rows.
> {code}
> '            Map Operator Tree:'
> '                TableScan'
> '                  alias: claims'
> '                  filterExpr: (typ_c = 3) (type: boolean)'
> '                  Statistics: Num rows: 1154941534 Data size: 4388777832 Basic stats:
COMPLETE Column stats: NONE'
> '                  GatherStats: false'
> '                  Filter Operator'
> '                    isSamplingPred: false'
> '                    predicate: (typ_c = 3) (type: boolean)'
> '                    Statistics: Num rows: 5 Data size: 19 Basic stats: COMPLETE Column
stats: NONE'
> {code}
> The estimation is in effect, as changing the estimate.percent changes this.
> {code}
> '                  filterExpr: (typ_c = 3) (type: boolean)'
> '                  Statistics: Num rows: 1154941534 Data size: 4388777832 Basic stats:
COMPLETE Column stats: NONE'
> '                  GatherStats: false'
> '                  Filter Operator'
> '                    isSamplingPred: false'
> '                    predicate: (typ_c = 3) (type: boolean)'
> '                    Statistics: Num rows: 230988307 Data size: 877755567 Basic stats:
COMPLETE Column stats: NONE'
> {code}



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