[jira] [Closed] (TRAFODION-1775) Raise a warning or error if UPDATE STATS is done w/o SAMPLE on a large table

["David Wayne Birdsall (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/TRAFODION-1775?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

David Wayne Birdsall closed TRAFODION-1775.
-------------------------------------------

Fixed in Release 2.0.

> Raise a warning or error if UPDATE STATS is done w/o SAMPLE on a large table
> ----------------------------------------------------------------------------
>
>                 Key: TRAFODION-1775
>                 URL: https://issues.apache.org/jira/browse/TRAFODION-1775
>             Project: Apache Trafodion
>          Issue Type: Improvement
>          Components: sql-cmp
>    Affects Versions: 2.0-incubating, 1.3-incubating
>         Environment: All
>            Reporter: David Wayne Birdsall
>            Assignee: David Wayne Birdsall
>             Fix For: 2.0-incubating
>
>
> If UPDATE STATISTICS is done on a very large table (say, 17 billion rows) without a SAMPLE clause, it can take hours to finish. The reason is that there is not enough memory to do things in memory, so it will in the worst case rescan the entire table for each histogram to create. The larger the table the worse it gets. 
> The suggestion, then, is to raise an error if this is done unless syntax overrides it. And in the latter case raise a warning.



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