admission: auto "CREATE STATS" integration

[aadityasondhi]

No description provided.

[blathers-crl]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

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[cockroach-teamcity]

This change is 

[yuzefovich]

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @aadityasondhi)

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pkg/sql/stats/automatic_stats.go line 901 at r1 (raw file):

	qosLevel := sessiondatapb.SystemLow
	log.Infof(ctx, "automatically executing %q", stmt)
	_ /* rows */, err := r.ex.ExecEx(

Hope you don't mind a drive-by question: does this change propagate all the way to TableReaders used by the distsql stats plan? My intuition says no ... I'd guess that this change is applied to the "CREATE STATISTICS ..." query which kicks off a separate execution plan, and that plan doesn't use the new QoS level.

[aadityasondhi]

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @yuzefovich)

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pkg/sql/stats/automatic_stats.go line 901 at r1 (raw file):

Previously, yuzefovich (Yahor Yuzefovich) wrote…

Hope you don't mind a drive-by question: does this change propagate all the way to TableReaders used by the distsql stats plan? My intuition says no ... I'd guess that this change is applied to the "CREATE STATISTICS ..." query which kicks off a separate execution plan, and that plan doesn't use the new QoS level.

I see, thanks for the callout. So the CREATE STATISTICS in this automatic_stats.go is not what is actually run? I am a little confused between this and the DistSQLPlanner.planAndRunCreateStats.

[yuzefovich]

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @aadityasondhi)

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pkg/sql/stats/automatic_stats.go line 901 at r1 (raw file):

Previously, aadityasondhi (Aaditya Sondhi) wrote…

I see, thanks for the callout. So the CREATE STATISTICS in this automatic_stats.go is not what is actually run? I am a little confused between this and the DistSQLPlanner.planAndRunCreateStats.

CREATE STATISTICS is kinda a delegated query, i.e. executing this statement results in effectively running another internal query (for which the distsql plan is constructed in planAndRunCreateStats.

More precisely, CREATE STATISTICS statements creates an AST with createStatsNode in it, then createStatsNode.startExec creates a job record, then - some time later - the jobs registry adopts this job, and when the job gets "resumed", then planAndRunCreateStats is invoked which actually collects table stats.