sql: TestRandomSyntaxFunctions skip schema telemetry job function

Previously, this test could depending on the concurrency,
could spawn a large number of schema telemetry jobs via
(ctdb_internal.create_sql_schema_telemetry_job).
This could lead to contention that will eventually
cause this test to time out. To address this, this
patch limits calling the telemetry job creation function.

Fixes: cockroachdb#108153

Release note: None

pkg/sql/tests/rsg_test.go

@@ -175,6 +175,7 @@ func (db *verifyFormatDB) execWithResettableTimeout(
 	}()
 	retry := true
 	targetDuration := duration
+	cancellationChannel := ctx.Done()
 	for retry {
 		retry = false
 		err := func() error {
@@ -202,7 +203,7 @@ func (db *verifyFormatDB) execWithResettableTimeout(
 					return &nonCrasher{sql: sql, err: err}
 				}
 				return nil
-			case <-ctx.Done():
+			case <-cancellationChannel:
 				// Sanity: The context is cancelled when the test is about to
 				// timeout. We will log whatever statement we're waiting on for
 				// debugging purposes. Sometimes queries won't respect
@@ -211,6 +212,7 @@ func (db *verifyFormatDB) execWithResettableTimeout(
 				// We will intentionally retry, which will us to wait for the
 				// go routine to complete above to avoid leaking it.
 				retry = true
+				cancellationChannel = nil
 				return nil
 			case <-time.After(targetDuration):
 				db.mu.Lock()
@@ -358,6 +360,10 @@ func TestRandomSyntaxFunctions(t *testing.T) {
 				switch lower {
 				case "pg_sleep":
 					continue
+				case "crdb_internal.create_sql_schema_telemetry_job":
+					// We can create a crazy number of telemtry jobs accidentally,
+					// within the test. Leading to terrible contention.
+					continue
 				case "crdb_internal.gen_rand_ident":
 					// Generates random identifiers, so a large number are dangerous and
 					// can take a long time.
@@ -437,6 +443,7 @@ func TestRandomSyntaxFunctions(t *testing.T) {
 		// involve schema changes like truncates. In general this should make
 		// this test more resilient as the timeouts are reset as long progress
 		// is made on *some* connection.
+		t.Logf("Running %q", s)
 		return db.execWithResettableTimeout(t, ctx, s, *flagRSGExecTimeout, *flagRSGGoRoutines)
 	})
 }