sql: introduce EXPLAIN ANALYZE (PLAN)

[RaduBerinde]

sql: introduce EXPLAIN ANALYZE (PLAN)

This change introduces a new variant of EXPLAIN ANALYZE which
executes the query and returns the execution plan (in the future,
annotated with stats from execution).

Note that (PLAN) is the default mode for the regular EXPLAIN.
Currently EXPLAIN ANALYZE defaults to (DISTSQL) mode, but we plan
to switch that default to the (PLAN) version once it is fully
implemented.

Release note (sql change): Added a new variant of explain: EXPLAIN
ANALYZE (PLAN).

sql: add planning and execution time to EXPLAIN ANALYZE (PLAN)

This commit adds planning and execution time as top-level fields in
EXPLAIN ANALYZE (PLAN). We also plumb a testing knob to allow these
fields to be deterministic in tests.

Release note: None

[cockroach-teamcity]

This change is 

[awoods187]

So exciting!!

[asubiotto]

Reviewed 9 of 9 files at r1, 5 of 5 files at r2.
Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @jordanlewis and @RaduBerinde)

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pkg/sql/conn_executor_exec.go, line 351 at r1 (raw file):

			ih.SetOutputMode(explainAnalyzeDebugOutput, explain.Flags{})
		} else {
			flags := explain.MakeFlags(&e.ExplainOptions)

Should we increment sqltelemetry.ExplainAnalyzeUseCounter here?

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pkg/sql/exec_util.go, line 834 at r2 (raw file):

	// EXPLAIN ANALYZE (PLAN) that can vary between runs (like elapsed times).
	// Should be set together with execinfra.TestingKnobs.DeterministicStats.
	DeterministicExplainAnalyze bool

Should we phase out DeterministicStats in favor of this one?

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pkg/sql/instrumentation.go, line 302 at r2 (raw file):

// planRows generates the plan tree as a list of strings (one for each line).
// Used in explainAnalyzePlanOutput mode.
func (ih *instrumentationHelper) planRows(phaseTimes *phaseTimes) []string {

nit: if this is only used for explain analyze, what do you think of renaming this method to planRowsForExplainAnalyze similar to planStringForBundle above?

[RaduBerinde]

TFTR!

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @asubiotto and @jordanlewis)

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pkg/sql/conn_executor_exec.go, line 351 at r1 (raw file):

Previously, asubiotto (Alfonso Subiotto Marqués) wrote…

Should we increment sqltelemetry.ExplainAnalyzeUseCounter here?

Done.

---

pkg/sql/exec_util.go, line 834 at r2 (raw file):

Previously, asubiotto (Alfonso Subiotto Marqués) wrote…

Should we phase out DeterministicStats in favor of this one?

I'd like there to be only one too, but they're knobs for different layers. I added a TODO for now.

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pkg/sql/instrumentation.go, line 302 at r2 (raw file):

Previously, asubiotto (Alfonso Subiotto Marqués) wrote…

nit: if this is only used for explain analyze, what do you think of renaming this method to planRowsForExplainAnalyze similar to planStringForBundle above?

Good idea, done.

[asubiotto]

Reviewed 4 of 4 files at r3.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @jordanlewis)

[RaduBerinde]

TFTR!

bors r+

[craig]

Canceled.

[RaduBerinde]

bors r+

[craig]

Build succeeded:

• GitHub CI (Cockroach)