From 3a84e126fc8e5b235bed96fe4ec265b26ff8dcf5 Mon Sep 17 00:00:00 2001
From: DrewKimball <drewk@cockroachlabs.com>
Date: Wed, 2 Nov 2022 03:03:45 +0000
Subject: [PATCH] opt: use RelExpr instead of ColumnID for reorderjoins
 relation map

The reorderjoins opttester directive previously maintained a map from
the first column ID of each base relation to the relation's label in
the output. This could cause a panic for relations that didn't output
any columns. This patch changes the map to use the relations themselves
as keys, which prevents the panic.

Release note: None
---
 .../opt/testutils/opttester/reorder_joins.go  |  15 +-
 pkg/sql/opt/xform/testdata/rules/join_order   | 180 +++++++++---------
 2 files changed, 95 insertions(+), 100 deletions(-)

diff --git a/pkg/sql/opt/testutils/opttester/reorder_joins.go b/pkg/sql/opt/testutils/opttester/reorder_joins.go
index ba712309d4db..4fe7ef73a73e 100644
--- a/pkg/sql/opt/testutils/opttester/reorder_joins.go
+++ b/pkg/sql/opt/testutils/opttester/reorder_joins.go
@@ -113,16 +113,15 @@ func (ot *OptTester) ReorderJoins() (string, error) {
 type joinOrderFormatter struct {
 	o *xform.Optimizer
 
-	// relLabels is a map from the first ColumnID of each base relation to its
-	// assigned label.
-	relLabels map[opt.ColumnID]string
+	// relLabels is a map from each base relation to its assigned label.
+	relLabels map[memo.RelExpr]string
 }
 
 // newJoinOrderFormatter returns an initialized joinOrderFormatter.
 func newJoinOrderFormatter(o *xform.Optimizer) *joinOrderFormatter {
 	return &joinOrderFormatter{
 		o:         o,
-		relLabels: make(map[opt.ColumnID]string),
+		relLabels: make(map[memo.RelExpr]string),
 	}
 }
 
@@ -195,11 +194,7 @@ func (jof *joinOrderFormatter) formatRules(rules []xform.OnReorderRuleParam) str
 // relLabel returns the label for the given relation. Labels will follow the
 // pattern A, B, ..., Z, A1, B1, etc.
 func (jof *joinOrderFormatter) relLabel(e memo.RelExpr) string {
-	firstCol, ok := e.Relational().OutputCols.Next(0)
-	if !ok {
-		panic(errors.AssertionFailedf("failed to retrieve column from %v", e.Op()))
-	}
-	if label, ok := jof.relLabels[firstCol]; ok {
+	if label, ok := jof.relLabels[e]; ok {
 		return label
 	}
 	const lenAlphabet = 26
@@ -210,7 +205,7 @@ func (jof *joinOrderFormatter) relLabel(e memo.RelExpr) string {
 		// Names will follow the pattern: A, B, ..., Z, A1, B1, etc.
 		label += strconv.Itoa(number)
 	}
-	jof.relLabels[firstCol] = label
+	jof.relLabels[e] = label
 	return label
 }
 
diff --git a/pkg/sql/opt/xform/testdata/rules/join_order b/pkg/sql/opt/xform/testdata/rules/join_order
index 2d1dd40f0ed4..db76612b070a 100644
--- a/pkg/sql/opt/xform/testdata/rules/join_order
+++ b/pkg/sql/opt/xform/testdata/rules/join_order
@@ -2002,14 +2002,14 @@ Join Tree #2
 Vertexes
   A:
     scan abc [as=a2]
-  B:
+  C:
     distinct-on
      └── scan abc [as=a5]
 Edges
-  a2.c = a5.c [inner, ses=AB, tes=AB, rules=()]
-Joining AB
-  A B [inner, refs=AB]
-  B A [inner, refs=AB]
+  a2.c = a5.c [inner, ses=AC, tes=AC, rules=()]
+Joining AC
+  A C [inner, refs=AC]
+  C A [inner, refs=AC]
 Joins Considered: 2
 --------------------------------------------------------------------------------
 Join Tree #3
@@ -2024,7 +2024,7 @@ Join Tree #3
    └── filters
         └── a1.a = a2.a
 Vertexes
-  C:
+  D:
     scan abc [as=a1]
   A:
     scan abc [as=a2]
@@ -2032,16 +2032,16 @@ Vertexes
     scan abc [as=a5]
 Edges
   a2.c = a5.c [semi, ses=AB, tes=AB, rules=()]
-  a1.a = a2.a [inner, ses=CA, tes=CA, rules=()]
-Joining CA
-  C A [inner, refs=CA]
-  A C [inner, refs=CA]
+  a1.a = a2.a [inner, ses=DA, tes=DA, rules=()]
+Joining DA
+  D A [inner, refs=DA]
+  A D [inner, refs=DA]
 Joining AB
   A B [semi, refs=AB]
-Joining CAB
-  C AB [inner, refs=CA]
-  AB C [inner, refs=CA]
-  CA B [semi, refs=AB]
+Joining DAB
+  D AB [inner, refs=DA]
+  AB D [inner, refs=DA]
+  DA B [semi, refs=AB]
 Joins Considered: 6
 --------------------------------------------------------------------------------
 Join Tree #4
@@ -2060,30 +2060,30 @@ Join Tree #4
    └── filters
         └── a2.b = a3.b
 Vertexes
-  C:
+  D:
     scan abc [as=a1]
-  A:
+  E:
     semi-join (hash)
      ├── scan abc [as=a2]
      ├── scan abc [as=a5]
      └── filters
           └── a2.c = a5.c
-  D:
+  F:
     scan abc [as=a3]
 Edges
-  a1.a = a2.a [inner, ses=CA, tes=CA, rules=()]
-  a2.b = a3.b [inner, ses=AD, tes=AD, rules=()]
-Joining CA
-  C A [inner, refs=CA]
-  A C [inner, refs=CA]
-Joining AD
-  A D [inner, refs=AD]
-  D A [inner, refs=AD]
-Joining CAD
-  C AD [inner, refs=CA]
-  AD C [inner, refs=CA]
-  CA D [inner, refs=AD]
-  D CA [inner, refs=AD]
+  a1.a = a2.a [inner, ses=DE, tes=DE, rules=()]
+  a2.b = a3.b [inner, ses=EF, tes=EF, rules=()]
+Joining DE
+  D E [inner, refs=DE]
+  E D [inner, refs=DE]
+Joining EF
+  E F [inner, refs=EF]
+  F E [inner, refs=EF]
+Joining DEF
+  D EF [inner, refs=DE]
+  EF D [inner, refs=DE]
+  DE F [inner, refs=EF]
+  F DE [inner, refs=EF]
 Joins Considered: 8
 --------------------------------------------------------------------------------
 Join Tree #5
@@ -2106,7 +2106,7 @@ Join Tree #5
    └── filters
         └── a3.a = a4.a
 Vertexes
-  C:
+  G:
     inner-join (hash)
      ├── scan abc [as=a1]
      ├── semi-join (hash)
@@ -2116,24 +2116,24 @@ Vertexes
      │         └── a2.c = a5.c
      └── filters
           └── a1.a = a2.a
-  D:
+  F:
     scan abc [as=a3]
-  E:
+  H:
     scan abc [as=a4]
 Edges
-  a2.b = a3.b [inner, ses=CD, tes=CD, rules=()]
-  a3.a = a4.a [inner, ses=DE, tes=DE, rules=()]
-Joining CD
-  C D [inner, refs=CD]
-  D C [inner, refs=CD]
-Joining DE
-  D E [inner, refs=DE]
-  E D [inner, refs=DE]
-Joining CDE
-  C DE [inner, refs=CD]
-  DE C [inner, refs=CD]
-  CD E [inner, refs=DE]
-  E CD [inner, refs=DE]
+  a2.b = a3.b [inner, ses=GF, tes=GF, rules=()]
+  a3.a = a4.a [inner, ses=FH, tes=FH, rules=()]
+Joining GF
+  G F [inner, refs=GF]
+  F G [inner, refs=GF]
+Joining FH
+  F H [inner, refs=FH]
+  H F [inner, refs=FH]
+Joining GFH
+  G FH [inner, refs=GF]
+  FH G [inner, refs=GF]
+  GF H [inner, refs=FH]
+  H GF [inner, refs=FH]
 Joins Considered: 8
 ================================================================================
 Final Plan
@@ -2253,29 +2253,29 @@ Vertexes
      ├── scan bx
      └── filters
           └── x IS NOT NULL
-  C:
+  D:
     distinct-on
      └── scan cy
 Edges
   a = x [inner, ses=AB, tes=AB, rules=()]
-  x = y [inner, ses=BC, tes=BC, rules=()]
-  a = y [inner, ses=AC, tes=AC, rules=()]
+  x = y [inner, ses=BD, tes=BD, rules=()]
+  a = y [inner, ses=AD, tes=AD, rules=()]
 Joining AB
   A B [inner, refs=AB]
   B A [inner, refs=AB]
-Joining AC
-  A C [inner, refs=AC]
-  C A [inner, refs=AC]
-Joining BC
-  B C [inner, refs=BC]
-  C B [inner, refs=BC]
-Joining ABC
-  A BC [inner, refs=AB]
-  BC A [inner, refs=AB]
-  B AC [inner, refs=AB]
-  AC B [inner, refs=AB]
-  AB C [inner, refs=BC]
-  C AB [inner, refs=BC]
+Joining AD
+  A D [inner, refs=AD]
+  D A [inner, refs=AD]
+Joining BD
+  B D [inner, refs=BD]
+  D B [inner, refs=BD]
+Joining ABD
+  A BD [inner, refs=AB]
+  BD A [inner, refs=AB]
+  B AD [inner, refs=AB]
+  AD B [inner, refs=AB]
+  AB D [inner, refs=BD]
+  D AB [inner, refs=BD]
 Joins Considered: 12
 --------------------------------------------------------------------------------
 Join Tree #4
@@ -2306,13 +2306,13 @@ Vertexes
           └── x IS NOT NULL
   C:
     scan cy
-  D:
+  E:
     scan dz
 Edges
   a = x [inner, ses=AB, tes=AB, rules=()]
   x = y [semi, ses=BC, tes=BC, rules=()]
-  a = z [inner, ses=AD, tes=AD, rules=(C->B)]
-  x = z [inner, ses=BD, tes=BD, rules=()]
+  a = z [inner, ses=AE, tes=AE, rules=(C->B)]
+  x = z [inner, ses=BE, tes=BE, rules=()]
 Joining AB
   A B [inner, refs=AB]
   B A [inner, refs=AB]
@@ -2322,31 +2322,31 @@ Joining ABC
   A BC [inner, refs=AB]
   BC A [inner, refs=AB]
   AB C [semi, refs=BC]
-Joining AD
-  A D [inner, refs=AD]
-  D A [inner, refs=AD]
-Joining BD
-  B D [inner, refs=BD]
-  D B [inner, refs=BD]
-Joining ABD
-  A BD [inner, refs=AB]
-  BD A [inner, refs=AB]
-  B AD [inner, refs=AB]
-  AD B [inner, refs=AB]
-  AB D [inner, refs=AD]
-  D AB [inner, refs=AD]
-Joining BCD
-  BD C [semi, refs=BC]
-  BC D [inner, refs=BD]
-  D BC [inner, refs=BD]
-Joining ABCD
-  A BCD [inner, refs=AB]
-  BCD A [inner, refs=AB]
-  ABD C [semi, refs=BC]
-  BC AD [inner, refs=AB]
-  AD BC [inner, refs=AB]
-  ABC D [inner, refs=AD]
-  D ABC [inner, refs=AD]
+Joining AE
+  A E [inner, refs=AE]
+  E A [inner, refs=AE]
+Joining BE
+  B E [inner, refs=BE]
+  E B [inner, refs=BE]
+Joining ABE
+  A BE [inner, refs=AB]
+  BE A [inner, refs=AB]
+  B AE [inner, refs=AB]
+  AE B [inner, refs=AB]
+  AB E [inner, refs=AE]
+  E AB [inner, refs=AE]
+Joining BCE
+  BE C [semi, refs=BC]
+  BC E [inner, refs=BE]
+  E BC [inner, refs=BE]
+Joining ABCE
+  A BCE [inner, refs=AB]
+  BCE A [inner, refs=AB]
+  ABE C [semi, refs=BC]
+  BC AE [inner, refs=AB]
+  AE BC [inner, refs=AB]
+  ABC E [inner, refs=AE]
+  E ABC [inner, refs=AE]
 Joins Considered: 26
 ================================================================================
 Final Plan