sql: turn off plan sampling by default

Previously, we were sampling plans for fingerprints
and saving to statement_statistics tables. Now that
we are saving plan hash and plan gist (that allow us
to decode back to the plan) we are no longer using the
sampled plan anywhere. Since this is a heavy opperation,
we are turning it off by default, but changing the default
value of `sql.metrics.statement_details.plan_collection.enabled`
to `false`.
If we don't receive feedback about turning it back on,
we can remove this sampling entirely.

Partially addresses #77944

Release note (sql change): Change the default value of
`sql.metrics.statement_details.plan_collection.enabled`
to false, since we no longer use this information
anywhere.

docs/generated/settings/settings-for-tenants.txt

@@ -150,7 +150,7 @@ sql.metrics.max_mem_stmt_fingerprints	integer	100000	the maximum number of state
 sql.metrics.max_mem_txn_fingerprints	integer	100000	the maximum number of transaction fingerprints stored in memory
 sql.metrics.statement_details.dump_to_logs	boolean	false	dump collected statement statistics to node logs when periodically cleared
 sql.metrics.statement_details.enabled	boolean	true	collect per-statement query statistics
-sql.metrics.statement_details.plan_collection.enabled	boolean	true	periodically save a logical plan for each fingerprint
+sql.metrics.statement_details.plan_collection.enabled	boolean	false	periodically save a logical plan for each fingerprint
 sql.metrics.statement_details.plan_collection.period	duration	5m0s	the time until a new logical plan is collected
 sql.metrics.statement_details.threshold	duration	0s	minimum execution time to cause statement statistics to be collected. If configured, no transaction stats are collected.
 sql.metrics.transaction_details.enabled	boolean	true	collect per-application transaction statistics

docs/generated/settings/settings.html

@@ -166,7 +166,7 @@
 <tr><td><code>sql.metrics.max_mem_txn_fingerprints</code></td><td>integer</td><td><code>100000</code></td><td>the maximum number of transaction fingerprints stored in memory</td></tr>
 <tr><td><code>sql.metrics.statement_details.dump_to_logs</code></td><td>boolean</td><td><code>false</code></td><td>dump collected statement statistics to node logs when periodically cleared</td></tr>
 <tr><td><code>sql.metrics.statement_details.enabled</code></td><td>boolean</td><td><code>true</code></td><td>collect per-statement query statistics</td></tr>
-<tr><td><code>sql.metrics.statement_details.plan_collection.enabled</code></td><td>boolean</td><td><code>true</code></td><td>periodically save a logical plan for each fingerprint</td></tr>
+<tr><td><code>sql.metrics.statement_details.plan_collection.enabled</code></td><td>boolean</td><td><code>false</code></td><td>periodically save a logical plan for each fingerprint</td></tr>
 <tr><td><code>sql.metrics.statement_details.plan_collection.period</code></td><td>duration</td><td><code>5m0s</code></td><td>the time until a new logical plan is collected</td></tr>
 <tr><td><code>sql.metrics.statement_details.threshold</code></td><td>duration</td><td><code>0s</code></td><td>minimum execution time to cause statement statistics to be collected. If configured, no transaction stats are collected.</td></tr>
 <tr><td><code>sql.metrics.transaction_details.enabled</code></td><td>boolean</td><td><code>true</code></td><td>collect per-application transaction statistics</td></tr>

pkg/ccl/telemetryccl/telemetry_logging_test.go

@@ -53,6 +53,10 @@ func TestTelemetryLogRegions(t *testing.T) {
 	sqlDB.Exec(t, `ALTER TABLE three_regions SPLIT AT SELECT generate_series(1, 3)`)
 	sqlDB.Exec(t, "ALTER TABLE three_regions EXPERIMENTAL_RELOCATE VALUES (ARRAY[1], 1), (ARRAY[2], 2), (ARRAY[3], 3)")
 
+	// Enable the sampling of all statements so that execution statistics
+	// (including the regions information) is collected.
+	sqlDB.Exec(t, `SET CLUSTER SETTING sql.txn_stats.sample_rate = 1.0`)
+
 	// Enable the telemetry logging and increase the sampling frequency so that
 	// all statements are captured.
 	sqlDB.Exec(t, `SET CLUSTER SETTING sql.telemetry.query_sampling.enabled = true;`)

pkg/server/status_test.go

@@ -1945,10 +1945,6 @@ func TestStatusAPIStatements(t *testing.T) {
 				// Ignore the ALTER USER ... VIEWACTIVITY statement.
 				continue
 			}
-			if len(respStatement.Stats.SensitiveInfo.MostRecentPlanDescription.Name) == 0 {
-				// Ensure that we populate the explain plan.
-				t.Fatal("expected MostRecentPlanDescription to be populated")
-			}
 			statementsInResponse = append(statementsInResponse, respStatement.Key.KeyData.Query)
 		}
 
@@ -2061,11 +2057,6 @@ func TestStatusAPICombinedStatements(t *testing.T) {
 				continue
 			}
 
-			if len(respStatement.Stats.SensitiveInfo.MostRecentPlanDescription.Name) == 0 {
-				// Ensure that we populate the explain plan.
-				t.Fatal("expected MostRecentPlanDescription to be populated")
-			}
-
 			statementsInResponse = append(statementsInResponse, respStatement.Key.KeyData.Query)
 		}
 

pkg/sql/instrumentation.go

@@ -220,11 +220,13 @@ func (ih *instrumentationHelper) Setup(
 	ih.savePlanForStats =
 		statsCollector.ShouldSaveLogicalPlanDesc(fingerprint, implicitTxn, p.SessionData().Database)
 
-	if ih.ShouldBuildExplainPlan() {
-		// Populate traceMetadata early in case we short-circuit the execution
-		// before reaching the bottom of this method.
-		ih.traceMetadata = make(execNodeTraceMetadata)
-	}
+	defer func() {
+		if ih.ShouldBuildExplainPlan() {
+			// Populate traceMetadata at the end once we have all properties of
+			// the helper setup.
+			ih.traceMetadata = make(execNodeTraceMetadata)
+		}
+	}()
 
 	if sp := tracing.SpanFromContext(ctx); sp != nil {
 		if sp.IsVerbose() {
@@ -270,9 +272,6 @@ func (ih *instrumentationHelper) Setup(
 	}
 
 	ih.collectExecStats = true
-	if ih.traceMetadata == nil {
-		ih.traceMetadata = make(execNodeTraceMetadata)
-	}
 	ih.evalCtx = p.EvalContext()
 	newCtx, ih.sp = tracing.EnsureChildSpan(ctx, cfg.AmbientCtx.Tracer, "traced statement", tracing.WithRecording(tracing.RecordingVerbose))
 	ih.shouldFinishSpan = true
@@ -424,7 +423,8 @@ func (ih *instrumentationHelper) ShouldUseJobForCreateStats() bool {
 // ShouldBuildExplainPlan returns true if we should build an explain plan and
 // call RecordExplainPlan.
 func (ih *instrumentationHelper) ShouldBuildExplainPlan() bool {
-	return ih.collectBundle || ih.savePlanForStats || ih.outputMode == explainAnalyzePlanOutput ||
+	return ih.collectBundle || ih.collectExecStats || ih.savePlanForStats ||
+		ih.outputMode == explainAnalyzePlanOutput ||
 		ih.outputMode == explainAnalyzeDistSQLOutput
 }
 

pkg/sql/sqlstats/cluster_settings.go

@@ -65,7 +65,7 @@ var SampleLogicalPlans = settings.RegisterBoolSetting(
 	settings.TenantWritable,
 	"sql.metrics.statement_details.plan_collection.enabled",
 	"periodically save a logical plan for each fingerprint",
-	true,
+	false,
 ).WithPublic()
 
 // LogicalPlanCollectionPeriod specifies the interval between collections of

pkg/sql/sqlstats/persistedsqlstats/datadriven_test.go

@@ -93,6 +93,10 @@ func TestSQLStatsDataDriven(t *testing.T) {
 	observerConn := cluster.ServerConn(1 /* idx */)
 
 	observer := sqlutils.MakeSQLRunner(observerConn)
+	_, err := sqlConn.Exec(`SET CLUSTER SETTING sql.metrics.statement_details.plan_collection.enabled = true;`)
+	if err != nil {
+		t.Errorf("failed to enable plan collection due to %s", err.Error())
+	}
 
 	execDataDrivenTestCmd := func(t *testing.T, d *datadriven.TestData) string {
 		switch d.Cmd {

pkg/util/log/logcrash/crash_reporting_packet_test.go

@@ -214,6 +214,10 @@ func TestInternalErrorReporting(t *testing.T) {
 
 	s, sqlDB, _ := serverutils.StartServer(t, base.TestServerArgs{})
 	defer s.Stopper().Stop(ctx)
+	_, err := sqlDB.Exec(`SET CLUSTER SETTING sql.metrics.statement_details.plan_collection.enabled = true;`)
+	if err != nil {
+		t.Errorf("failed to enable plan collection due to %s", err.Error())
+	}
 
 	if _, err := sqlDB.Exec("SELECT crdb_internal.force_assertion_error('woo')"); !testutils.IsError(err, "internal error") {
 		t.Fatalf("expected internal error, got %v", err)