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https://issues.apache.org/jira/browse/HIVE-3917?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13564904#comment-13564904
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Gang Tim Liu commented on HIVE-3917:
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We don't distinguish them.
Note that the stale stats has been in hive for a while NOT introduced by
"noscan". For example, a few places, stats are not calculated completely like
alter table ... set location ...
We'd like to make statistics more accurate. It involves fixes of those holes,
add the flag to tell us what statistics are accurate and what are not.
We can discuss more on HIVE-3954.
> Support fast operation for analyze command
> ------------------------------------------
>
> Key: HIVE-3917
> URL: https://issues.apache.org/jira/browse/HIVE-3917
> Project: Hive
> Issue Type: Improvement
> Components: Statistics
> Affects Versions: 0.11.0
> Reporter: Gang Tim Liu
> Assignee: Gang Tim Liu
> Attachments: HIVE-3917.patch.1
>
>
> hive supports analyze command to gather statistics from existing
> tables/partition
> https://cwiki.apache.org/confluence/display/Hive/StatsDev#StatsDev-ExistingTables
> It collects:
> 1. Number of Rows
> 2. Number of files
> 3. Size in Bytes
> If table/partition is big, the operation would take time since it will open
> all files and scan all data.
> It would be nice to support fast operation to gather statistics which doesn't
> require to open all files:
> 1. Number of files
> 2. Size in Bytes
> Potential syntax is
> ANALYZE TABLE tablename [PARTITION(partcol1[=val1], partcol2[=val2], ...)]
> COMPUTE STATISTICS [noscan];
> In the future, all statistics without scan can be retrieved via this optional
> parameter.
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