Merge pull request #117454 from cockroachdb/blathers/backport-release…

…-23.2.0-rc-117433

release-23.2.0-rc: sql: do not re-run optbuild before collecting index recommendations

pkg/sql/instrumentation.go

@@ -1044,21 +1044,27 @@ func (ih *instrumentationHelper) SetIndexRecommendations(
 			recommendations = ih.explainIndexRecs
 		} else {
 			opc := &planner.optPlanningCtx
-			opc.reset(ctx)
 			f := opc.optimizer.Factory()
-			evalCtx := opc.p.EvalContext()
-			f.Init(ctx, evalCtx, opc.catalog)
-			f.FoldingControl().AllowStableFolds()
-			bld := optbuilder.New(ctx, &opc.p.semaCtx, evalCtx, opc.catalog, f, opc.p.stmt.AST)
-			err := bld.Build()
-			if err != nil {
-				log.Warningf(ctx, "unable to build memo: %s", err)
-			} else {
-				recommendations, err = opc.makeQueryIndexRecommendation(ctx)
+			if f.Memo() == nil || f.Memo().IsEmpty() {
+				// Run optbuild to create a memo with a root expression, if the current
+				// memo is empty.
+				opc.reset(ctx)
+				evalCtx := opc.p.EvalContext()
+				f.Init(ctx, evalCtx, opc.catalog)
+				f.FoldingControl().AllowStableFolds()
+				bld := optbuilder.New(ctx, &opc.p.semaCtx, evalCtx, opc.catalog, f, opc.p.stmt.AST)
+				err := bld.Build()
 				if err != nil {
-					log.Warningf(ctx, "unable to generate index recommendations: %s", err)
+					log.Warningf(ctx, "unable to build memo: %s", err)
+					return
 				}
 			}
+			var err error
+			recommendations, err = opc.makeQueryIndexRecommendation(ctx)
+			if err != nil {
+				log.Warningf(ctx, "unable to generate index recommendations: %s", err)
+				return
+			}
 		}
 		reset = true
 	}

pkg/sql/logictest/testdata/logic_test/index_recommendations

@@ -0,0 +1,107 @@
+# LogicTest: local
+
+# Regression test for #117307.
+
+statement ok
+SET CLUSTER SETTING sql.metrics.statement_details.index_recommendation_collection.enabled = true
+
+statement ok
+SET enable_insert_fast_path = true
+
+statement ok
+CREATE TABLE b (b INT PRIMARY KEY)
+
+statement ok
+CREATE TABLE c (c INT PRIMARY KEY)
+
+statement ok
+CREATE TABLE d (d INT PRIMARY KEY)
+
+statement ok
+CREATE TABLE abcd (
+  a INT NOT NULL PRIMARY KEY,
+  b INT NULL REFERENCES b (b),
+  c INT NULL REFERENCES c (c),
+  d INT NULL REFERENCES d (d),
+  INDEX (b),
+  INDEX (c),
+  INDEX (d)
+)
+
+statement ok
+INSERT INTO b VALUES (0), (1), (2), (3), (4), (5)
+
+statement ok
+INSERT INTO c VALUES (0), (1), (2), (3), (4), (5)
+
+statement ok
+INSERT INTO d VALUES (0), (1), (2), (3), (4)
+
+# We need 5 previous executions to turn on index recommendation collection.
+
+statement ok
+PREPARE p0 AS INSERT INTO abcd VALUES ($1, $2, $3, $4)
+
+statement ok
+EXECUTE p0(0, 0, 0, 0)
+
+statement ok
+DEALLOCATE p0
+
+statement ok
+PREPARE p1 AS INSERT INTO abcd VALUES ($1, $2, $3, $4)
+
+statement ok
+EXECUTE p1(1, 1, 1, 1)
+
+statement ok
+DEALLOCATE p1
+
+statement ok
+PREPARE p2 AS INSERT INTO abcd VALUES ($1, $2, $3, $4)
+
+statement ok
+EXECUTE p2(2, 2, 2, 2)
+
+statement ok
+DEALLOCATE p2
+
+statement ok
+PREPARE p3 AS INSERT INTO abcd VALUES ($1, $2, $3, $4)
+
+statement ok
+EXECUTE p3(3, 3, 3, 3)
+
+statement ok
+DEALLOCATE p3
+
+statement ok
+PREPARE p4 AS INSERT INTO abcd VALUES ($1, $2, $3, $4)
+
+statement ok
+EXECUTE p4(4, 4, 4, 4)
+
+statement ok
+DEALLOCATE p4
+
+# To hit the bug, we need a combination of:
+# - index recommendation collection
+# - prepared statement
+# - insert fast path with multiple FK checks
+# - one FK check can be skipped due to NULL value
+# - last FK check fails
+
+statement ok
+PREPARE p5 AS INSERT INTO abcd VALUES ($1, $2, $3, $4)
+
+statement error pq: insert on table "abcd" violates foreign key constraint "abcd_d_fkey"\nDETAIL: Key \(d\)=\(5\) is not present in table "d"
+EXECUTE p5(5, 5, NULL, 5)
+
+statement ok
+DEALLOCATE p5
+
+statement ok
+RESET CLUSTER SETTING sql.metrics.statement_details.index_recommendation_collection.enabled
+
+statement ok
+RESET enable_insert_fast_path