Merge pull request cockroachdb#86804 from DrewKimball/backport22.1-86193

release-22.1: opt: use only required columns in provided ordering for project

pkg/sql/opt/ordering/project.go

@@ -14,6 +14,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/opt"
 	"github.com/cockroachdb/cockroach/pkg/sql/opt/memo"
 	"github.com/cockroachdb/cockroach/pkg/sql/opt/props"
+	"github.com/cockroachdb/errors"
 )
 
 func projectCanProvideOrdering(expr memo.RelExpr, required *props.OrderingChoice) bool {
@@ -74,13 +75,24 @@ func projectOrderingToInput(
 }
 
 func projectBuildProvided(expr memo.RelExpr, required *props.OrderingChoice) opt.Ordering {
-	p := expr.(*memo.ProjectExpr)
+	// Ensure that the child provided ordering only refers to columns from the
+	// required ordering choice. This is necessary because there may be cases
+	// where the input of the Project has undergone transformations that allow it
+	// to "see" more functional dependencies than the original memo group. This
+	// can cause the child to provide an ordering that is equivalent to the
+	// required ordering, but which the parent Project cannot prove is equivalent
+	// because its FDs have less information. This can lead to a panic later on.
+	ordCols := required.ColSet()
+	if !ordCols.SubsetOf(expr.Relational().OutputCols) {
+		panic(errors.AssertionFailedf("expected required columns to be a subset of output columns"))
+	}
 	// Project can only satisfy required orderings that refer to projected
 	// columns; it should always be possible to remap the columns in the input's
 	// provided ordering.
+	p := expr.(*memo.ProjectExpr)
 	return remapProvided(
 		p.Input.ProvidedPhysical().Ordering,
 		p.InternalFDs(),
-		p.Relational().OutputCols,
+		ordCols,
 	)
 }

pkg/sql/opt/xform/testdata/physprops/ordering

@@ -2571,3 +2571,41 @@ project
       │         ├── name:2 = name:8 [outer=(2,8), fd=(2)==(8), (8)==(2)]
       │         └── k:7::STRING = lower(name:8) [outer=(7,8), immutable]
       └── 56
+
+# Regression test for #85393 - use only columns from the required ordering when
+# building the provided ordering for Project operators.
+exec-ddl
+CREATE TABLE t0_85393 (c0 INT);
+----
+
+exec-ddl
+CREATE TABLE t1_85393 (c0 INT);
+----
+
+opt
+SELECT *
+FROM t0_85393 CROSS JOIN t1_85393
+WHERE (t0_85393.rowid IS NULL) OR (t1_85393.rowid IN (t0_85393.rowid))
+ORDER BY t1_85393.rowid;
+----
+sort
+ ├── columns: c0:1 c0:5  [hidden: t1_85393.rowid:6!null]
+ ├── fd: (6)-->(5)
+ ├── ordering: +6
+ └── project
+      ├── columns: t0_85393.c0:1 t1_85393.c0:5 t1_85393.rowid:6!null
+      ├── fd: (6)-->(5)
+      └── inner-join (cross)
+           ├── columns: t0_85393.c0:1 t0_85393.rowid:2!null t1_85393.c0:5 t1_85393.rowid:6!null
+           ├── key: (2,6)
+           ├── fd: (2)-->(1), (6)-->(5)
+           ├── scan t0_85393
+           │    ├── columns: t0_85393.c0:1 t0_85393.rowid:2!null
+           │    ├── key: (2)
+           │    └── fd: (2)-->(1)
+           ├── scan t1_85393
+           │    ├── columns: t1_85393.c0:5 t1_85393.rowid:6!null
+           │    ├── key: (6)
+           │    └── fd: (6)-->(5)
+           └── filters
+                └── (t0_85393.rowid:2 IS NULL) OR (t1_85393.rowid:6 = t0_85393.rowid:2) [outer=(2,6)]