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https://issues.apache.org/jira/browse/HIVE-21344?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16950708#comment-16950708
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Jesus Camacho Rodriguez commented on HIVE-21344:
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[~ashutoshc], fwiw the refresh is incremental: for those materialized views
that are up-to-date, reload is a no-op, and we only end up reloading in the
registry those that are missing or are not up-to-date. I'll create a new JIRA
to change the default.
> CBO: Reduce compilation time in presence of materialized views
> --------------------------------------------------------------
>
> Key: HIVE-21344
> URL: https://issues.apache.org/jira/browse/HIVE-21344
> Project: Hive
> Issue Type: Bug
> Components: Materialized views
> Affects Versions: 4.0.0
> Reporter: Gopal Vijayaraghavan
> Assignee: Jesus Camacho Rodriguez
> Priority: Major
> Labels: pull-request-available
> Fix For: 4.0.0
>
> Attachments: HIVE-21344.01.patch, HIVE-21344.02.patch,
> HIVE-21344.03.patch, HIVE-21344.04.patch, HIVE-21344.05.patch,
> HIVE-21344.patch, calcite-planner-after-fix.svg.zip, mv-get-from-remote.png
>
> Time Spent: 1h
> Remaining Estimate: 0h
>
> For every query, {{getAllValidMaterializedViews}} still requires a call to
> metastore to verify that the materializations exist, whether they are
> outdated or not, etc. Since this is only useful for active-active HS2
> deployments, we could take a less aggressive approach and check this
> information only after rewriting has been triggered. In addition, we could
> refresh the information in the HS2 registry periodically in a background
> thread.
> {code}
> // This is not a rebuild, we retrieve all the materializations. In turn, we
> do not need
> // to force the materialization contents to be up-to-date, as this is not a
> rebuild, and
> // we apply the user parameters
> (HIVE_MATERIALIZED_VIEW_REWRITING_TIME_WINDOW) instead.
> materializations = db.getAllValidMaterializedViews(getTablesUsed(basePlan),
> false, getTxnMgr());
> {code}
> !mv-get-from-remote.png!
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