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https://issues.apache.org/jira/browse/HIVE-18395?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16323133#comment-16323133
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Steve Yeom commented on HIVE-18395:
-----------------------------------
Talked with Ashutosh.
1. The current system regarding stats gathering and using
- The system updates Metastore stats only for insert statements for non-acid
tables (keep in mind that only insert is supported for
non-acid tables).
- Per table COLUMN_STATS_ACCURATE key and its value pair and other table
stats are from TABLE_PARAMS table in the Metastore.
A updater/inserter sets to false this flag when its corresponding StatsTask
fails.
Subsequent reader statement uses this flag value to determine whether to
use stats for an aggregate statement.
Note that a precondition for this flag to work is that any table data and
its metadata updater operation should use this flag.
> Using stats for aggregates on Acid/MM is off even with
> "hive.compute.query.using.stats" is true.
> ------------------------------------------------------------------------------------------------
>
> Key: HIVE-18395
> URL: https://issues.apache.org/jira/browse/HIVE-18395
> Project: Hive
> Issue Type: Bug
> Affects Versions: 3.0.0
> Reporter: Steve Yeom
> Priority: Minor
>
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