planner: fix bugs related to TIDB_INLJ hint (#11253) (#11362)

planner/core/exhaust_physical_plans.go

@@ -1030,15 +1030,19 @@ func (p *LogicalJoin) tryToGetIndexJoin(prop *property.PhysicalProperty) (indexJ
  }
 
  if leftJoins != nil && lhsCardinality < rhsCardinality {
- return leftJoins, hasIndexJoinHint
+ return leftJoins, leftOuter
  }
 
  if rightJoins != nil && rhsCardinality < lhsCardinality {
- return rightJoins, hasIndexJoinHint
+ return rightJoins, rightOuter
  }
 
+ canForceLeft := leftJoins != nil && leftOuter
+ canForceRight := rightJoins != nil && rightOuter
+ forced = canForceLeft || canForceRight
+
  joins := append(leftJoins, rightJoins...)
- return joins, hasIndexJoinHint && len(joins) != 0
+ return joins, forced
  }
 
  return nil, false

planner/core/logical_plan_builder.go

@@ -310,8 +310,17 @@ func (p *LogicalJoin) extractOnCondition(conditions []expression.Expression, der
  return
 }
 
+// extractTableAlias returns table alias of the LogicalPlan's columns.
+// It will return nil when there are multiple table alias, because the alias is only used to check if
+// the logicalPlan match some optimizer hints, and hints are not expected to take effect in this case.
 func extractTableAlias(p LogicalPlan) *model.CIStr {
  if p.Schema().Len() > 0 && p.Schema().Columns[0].TblName.L != "" {
+ tblName := p.Schema().Columns[0].TblName.L
+ for _, column := range p.Schema().Columns {
+ if column.TblName.L != tblName {
+ return nil
+ }
+ }
  return &(p.Schema().Columns[0].TblName)
  }
  return nil

planner/core/physical_plan_test.go

@@ -1518,3 +1518,52 @@ func (s *testPlanSuite) TestUnmatchedTableInHint(c *C) {
  }
  }
 }
+
+func (s *testPlanSuite) TestIndexJoinHint(c *C) {
+ defer testleak.AfterTest(c)()
+ store, dom, err := newStoreWithBootstrap()
+ c.Assert(err, IsNil)
+ defer func() {
+ dom.Close()
+ store.Close()
+ }()
+ se, err := session.CreateSession4Test(store)
+ c.Assert(err, IsNil)
+ _, err = se.Execute(context.Background(), "use test")
+ c.Assert(err, IsNil)
+
+ tests := []struct {
+ sql string
+ best string
+ warning string
+ }{
+ {
+ sql: "select /*+ TIDB_INLJ(t1) */ t1.a, t2.a, t3.a from t t1, t t2, t t3 where t1.a = t2.a and t2.a = t3.a;",
+ best: "MergeInnerJoin{TableReader(Table(t))->IndexJoin{TableReader(Table(t))->TableReader(Table(t))}(test.t2.a,test.t1.a)}(test.t3.a,test.t2.a)->Projection",
+ warning: "",
+ },
+ {
+ sql: "select /*+ TIDB_INLJ(t1) */ t1.b, t2.a from t t1, t t2 where t1.b = t2.a;",
+ best: "LeftHashJoin{TableReader(Table(t))->TableReader(Table(t))}(test.t1.b,test.t2.a)",
+ warning: "[planner:1815]Optimizer Hint /*+ TIDB_INLJ(t1) */ is inapplicable",
+ },
+ }
+ for i, test := range tests {
+ comment := Commentf("case:%v sql:%s", i, test)
+ stmt, err := s.ParseOneStmt(test.sql, "", "")
+ c.Assert(err, IsNil, comment)
+
+ p, err := planner.Optimize(se, stmt, s.is)
+ c.Assert(err, IsNil)
+ c.Assert(core.ToString(p), Equals, test.best)
+
+ warnings := se.GetSessionVars().StmtCtx.GetWarnings()
+ if test.warning == "" {
+ c.Assert(len(warnings), Equals, 0)
+ } else {
+ c.Assert(len(warnings), Equals, 1)
+ c.Assert(warnings[0].Level, Equals, stmtctx.WarnLevelWarning)
+ c.Assert(warnings[0].Err.Error(), Equals, test.warning)
+ }
+ }
+}