exeuctor: add a helper variable to help ga hash join v2 step by step for all kinds of join types (#57116)

ref #53127

Author: windtalker

pkg/executor/join/joinversion/join_version.go

@@ -25,6 +25,20 @@ const (
 	HashJoinVersionOptimized = "optimized"
 )
 
+var (
+	// UseHashJoinV2ForNonGAJoin is added because Hash join contains a lots of types(like inner join, outer join, semi join, nullaware semi join, etc)
+	// we want to GA these different kind of joins step by step, but don't want to add a new session variable for each of the join,
+	// so we add this variable to control whether to use hash join v2 for nonGA joins(enable it for test, disable it in a release version).
+	// PhysicalHashJoin.isGAForHashJoinV2() defines whether the join is GA for hash join v2, we can make each join GA separately by updating
+	// this function one by one
+	UseHashJoinV2ForNonGAJoin = false
+)
+
+func init() {
+	// This variable is set to true for test, need to be set back to false in release version
+	UseHashJoinV2ForNonGAJoin = true
+}
+
 // IsOptimizedVersion returns true if hashJoinVersion equals to HashJoinVersionOptimized
 func IsOptimizedVersion(hashJoinVersion string) bool {
 	return strings.ToLower(hashJoinVersion) == HashJoinVersionOptimized

pkg/planner/core/BUILD.bazel

@@ -96,6 +96,7 @@ go_library(
         "//pkg/distsql",
         "//pkg/domain",
         "//pkg/errctx",
+        "//pkg/executor/join/joinversion",
         "//pkg/expression",
         "//pkg/expression/aggregation",
         "//pkg/expression/exprctx",

pkg/planner/core/physical_plans.go

@@ -21,6 +21,7 @@ import (
 	"unsafe"
 
 	"github.com/pingcap/errors"
+	"github.com/pingcap/tidb/pkg/executor/join/joinversion"
 	"github.com/pingcap/tidb/pkg/expression"
 	"github.com/pingcap/tidb/pkg/expression/aggregation"
 	"github.com/pingcap/tidb/pkg/kv"
@@ -1472,8 +1473,34 @@ type PhysicalHashJoin struct {
 	runtimeFilterList []*RuntimeFilter `plan-cache-clone:"must-nil"` // plan with runtime filter is not cached
 }
 
+func (p *PhysicalHashJoin) isGAForHashJoinV2() bool {
+	// nullaware join
+	if len(p.LeftNAJoinKeys) > 0 {
+		return false
+	}
+	// cross join
+	if len(p.LeftJoinKeys) == 0 {
+		return false
+	}
+	// join with null equal condition
+	for _, value := range p.IsNullEQ {
+		if value {
+			return false
+		}
+	}
+	switch p.JoinType {
+	case logicalop.LeftOuterJoin, logicalop.RightOuterJoin, logicalop.InnerJoin:
+		return true
+	default:
+		return false
+	}
+}
+
 // CanUseHashJoinV2 returns true if current join is supported by hash join v2
 func (p *PhysicalHashJoin) CanUseHashJoinV2() bool {
+	if !p.isGAForHashJoinV2() && !joinversion.UseHashJoinV2ForNonGAJoin {
+		return false
+	}
 	switch p.JoinType {
 	case logicalop.LeftOuterJoin, logicalop.RightOuterJoin, logicalop.InnerJoin:
 		// null aware join is not supported yet