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disable_merge_join corner case #2901

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Merged
merged 1 commit into from
Mar 20, 2025
Merged

disable_merge_join corner case #2901

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14 changes: 12 additions & 2 deletions enginetest/join_planning_tests.go
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Original file line number Diff line number Diff line change
Expand Up @@ -87,15 +87,20 @@ var JoinPlanningTests = []joinPlanScript{
"CREATE table ab (a int primary key, b int);",
"insert into xy values (1,0), (2,1), (0,2), (3,3);",
"insert into ab values (0,2), (1,2), (2,2), (3,1);",
`analyze table xy update histogram on x using data '{"row_count":1000}'`,
`analyze table ab update histogram on a using data '{"row_count":1000}'`,
`analyze table xy update histogram on x using data '{"row_count":1000000}'`,
`analyze table ab update histogram on a using data '{"row_count":1000000}'`,
},
tests: []JoinPlanTest{
{
q: "select /*+ JOIN_ORDER(ab, xy) MERGE_JOIN(ab, xy)*/ * from ab join xy on y = a order by 1, 3",
types: []plan.JoinType{plan.JoinTypeMerge},
exp: []sql.Row{{0, 2, 1, 0}, {1, 2, 2, 1}, {2, 2, 0, 2}, {3, 1, 3, 3}},
},
{
q: "select * from ab join xy on x = a and y = a order by 1, 3",
types: []plan.JoinType{plan.JoinTypeMerge},
exp: []sql.Row{{3, 1, 3, 3}},
},
{
q: "set @@SESSION.disable_merge_join = 1",
exp: []sql.Row{{}},
Expand All @@ -105,6 +110,11 @@ var JoinPlanningTests = []joinPlanScript{
types: []plan.JoinType{plan.JoinTypeLookup},
exp: []sql.Row{{0, 2, 1, 0}, {1, 2, 2, 1}, {2, 2, 0, 2}, {3, 1, 3, 3}},
},
{
q: "select * from ab join xy on x = a and y = a order by 1, 3",
types: []plan.JoinType{plan.JoinTypeLookup},
exp: []sql.Row{{3, 1, 3, 3}},
},
},
},
{
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2 changes: 1 addition & 1 deletion sql/memo/select_hints.go
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Expand Up @@ -390,7 +390,7 @@ type joinHints struct {
}

func (h joinHints) isEmpty() bool {
return len(h.ops) == 0 && h.order == nil && !h.leftDeep
return len(h.ops) == 0 && h.order == nil && !h.leftDeep && len(h.block) == 0
}

// satisfiedBy returns whether a RelExpr satisfies every join hint. This
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