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Posted to issues@spark.apache.org by "Hyukjin Kwon (JIRA)" <ji...@apache.org> on 2019/05/21 04:03:07 UTC
[jira] [Updated] (SPARK-15302) Implement FK/PK "rely novalidate"
constraints for better CBO
[ https://issues.apache.org/jira/browse/SPARK-15302?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Hyukjin Kwon updated SPARK-15302:
---------------------------------
Labels: bulk-closed (was: )
> Implement FK/PK "rely novalidate" constraints for better CBO
> ------------------------------------------------------------
>
> Key: SPARK-15302
> URL: https://issues.apache.org/jira/browse/SPARK-15302
> Project: Spark
> Issue Type: New Feature
> Components: Optimizer, Spark Core
> Affects Versions: 2.0.0
> Reporter: Ruslan Dautkhanov
> Priority: Major
> Labels: bulk-closed
>
> Oracle has "RELY NOVALIDATE" option for constraints.. Could be easier for Hive to start with something like that for PK/FK constraints. So CBO has more information for optimizations. It does not have to actually check if that constraint is relationship is true; it can just "rely" on that constraint.
> RELY clause:
> https://docs.oracle.com/database/121/SQLRF/clauses002.htm#SQLRF52223
> "Overview of Constraint States":
> https://docs.oracle.com/database/121/DWHSG/schemas.htm#DWHSG9053
> - Enforcement
> - Validation
> - Belief
> So FK/PK with "rely novalidate" will have Enforcement&Validate disabled but Belief = RELY as it is possible to do in Oracle and now in Hive (HIVE-13076).
> It opens a lot of ways to do additional ways to optimize execution plans.
> As explained in Tom Kyte's "Metadata matters"
> http://www.peoug.org/wp-content/uploads/2009/12/MetadataMatters_PEOUG_Day2009_TKyte.pdf
> pp.30 - "Tell us how the tables relate and we can remove them from the plan...".
> pp.35 - "Tell us how the tables relate and we have more access paths available...".
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