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Posted to issues-all@impala.apache.org by "ASF subversion and git services (JIRA)" <ji...@apache.org> on 2018/11/07 21:29:00 UTC
[jira] [Commented] (IMPALA-3531) Implement FK/PK "rely novalidate"
constraints for better CBO
[ https://issues.apache.org/jira/browse/IMPALA-3531?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16678793#comment-16678793 ]
ASF subversion and git services commented on IMPALA-3531:
---------------------------------------------------------
Commit 04695f4ed8e66aec117ab64cf6e56f62ef93d865 in impala's branch refs/heads/master from Bharath Vissapragada
[ https://git-wip-us.apache.org/repos/asf?p=impala.git;h=04695f4 ]
Bump CDH_BUILD_VERSION to include Hive fix for RELY constraint
This change bumps the CDH_BUILD_VERSION to a version that includes
the fix for a bug that does not correctly propagate "RELY" constraints
from SQL statements in Hive. This is needed for the upcoming patch for
IMPALA-3531.
This new CDH_BUILD_VERSION pulls in newer version of Kudu binaries (v1.9).
Kudu version variables in the impala-config are updated accordingly. Also,
includes a newer toolchain build that has these v1.9 bits.
Testing: DEBUG/Core tests passed.
Change-Id: Ie626882044fea98b81b07caa950b480e16df122d
Reviewed-on: http://gerrit.cloudera.org:8080/11891
Tested-by: Impala Public Jenkins <im...@cloudera.com>
Reviewed-by: Thomas Marshall <th...@cmu.edu>
> Implement FK/PK "rely novalidate" constraints for better CBO
> ------------------------------------------------------------
>
> Key: IMPALA-3531
> URL: https://issues.apache.org/jira/browse/IMPALA-3531
> Project: IMPALA
> Issue Type: New Feature
> Components: Catalog, Frontend, Perf Investigation
> Affects Versions: Impala 2.5.0, Impala 2.6.0
> Environment: CDH
> Reporter: Ruslan Dautkhanov
> Priority: Minor
> Labels: CBO, performance, ramp-up
>
> 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.
> https://docs.oracle.com/database/121/SQLRF/clauses002.htm#sthref2289
> So it would be helpful with join cardinality estimates, and with cases like IMPALA-2929.
> https://docs.oracle.com/database/121/DWHSG/schemas.htm#DWHSG9053
> "Overview of Constraint States":
> - 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 exxplined 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...".
> Also it might be helpful when Impala is being integrated with Kudu as the latter have to have a PK.
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