release-20.1: sql: add cache for jobs to avoid querying system.jobs to find existing jobs#50923
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RichardJCai merged 1 commit intocockroachdb:release-20.1from Jul 2, 2020
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Wait this (and the original PR) need a release note about the performance regression that was fixed. |
ajwerner
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good catch. Otherwise
Reviewed 5 of 5 files at r1.
Reviewable status:complete! 1 of 0 LGTMs obtained (waiting on @rohany)
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Ah true, what should I do about the original PR? |
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I don't know... Ask in the slack? |
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…ng job Currently, we perform a loop through all existing jobs which involves querying a system table to check if there is an existing job for the current table undergoing a schema change. To avoid this query, we can use a cache to map TableIDs to jobs. Fixes cockroachdb#50165, cockroachdb#50783 Release note (bug fix): Fixed regression where granting privileges and dropping objects would be slow when performed on a large number of objects due to unnecessary queries for looking up jobs in the system.jobs. Previously we did a quadratic number of queries based on the number of objects. After this fix we do a linear number of queries based on the number of objects which significantly improves the speed of dropping multiple objects or granting multiple privileges to a user.
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Backport 1/1 commits from #50848.
/cc @cockroachdb/release
Currently, we perform a loop through all existing jobs which involves
querying a system table to check if there is an existing job for the current
table undergoing a schema change. To avoid this query, we can use a cache
to map TableIDs to jobs.
Fixes #50165, #50783
Release note (bug fix): Fixed regression where granting privileges and dropping objects
would be slow when performed on a large number of objects due to unnecessary queries
for looking up jobs in the system.jobs.
Previously we did a quadratic number of queries based on the number of objects.
After this fix we do a linear number of queries based on the number of objects which
significantly improves the speed of dropping multiple objects or granting
multiple privileges to a user.