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https://issues.apache.org/jira/browse/TRAFODION-1494?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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David Wayne Birdsall closed TRAFODION-1494.
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Fixed in Release 1.3.
> UPDATE STATS sample table population query gets serial plan
> -----------------------------------------------------------
>
> Key: TRAFODION-1494
> URL: https://issues.apache.org/jira/browse/TRAFODION-1494
> Project: Apache Trafodion
> Issue Type: Bug
> Components: sql-cmp
> Affects Versions: 1.1 (pre-incubation)
> Environment: All
> Reporter: David Wayne Birdsall
> Assignee: David Wayne Birdsall
> Fix For: 1.2-incubating
>
> Original Estimate: 1h
> Remaining Estimate: 1h
>
> If a table is large enough so that sample data does not fit in memory, UPDATE
> STATS will create a table and use an UPSERT or LOAD statement to load it with
> a sample of the table of interest. The query plan being generated for this
> UPSERT/LOAD is a serial plan which is quite slow. It should generate a
> parallel plan.
> The problem is in CmpSeabaseDDL::restoreAllControlsAndFlags. We set a bunch
> of CQDs for metadata queries so their plans are not affected by any user
> CQDs. The procedure CmpSeabaseDDL::restoreAllControlsAndFlags is in charge of
> restoring the CQDs afterward, but fails to.
> One of the CQDs that fails to get reset is "attempt_esp_parallelism". It is
> turned OFF for the metadata queries. Since it does not get reset, all plans
> afterward (including sample table population) are serial.
> The bug is in the following statement in
> CmpSeabaseDDL::restoreAllControlsAndFlags:
> if (CmpCommon::context()->getCntlCount() > 0 &&
> CmpCommon::context()->getCntlCount() < CQD_SENT_MAX)
> The "<" should be a "<=". (Off-by-one bug.)
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