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Commit1b4cc49

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Preserve AND/OR flatness while extracting restriction OR clauses.
The code I added in commitf343a88 wascareless about preserving AND/OR flatness: it could create a structure withan OR node directly underneath another one. That breaks an assumptionthat's fairly important for planning efficiency, not to mention triggeringvarious Asserts (as reported by Benjamin Smith). Add a trifle more logicto handle the case properly.
1 parent07c8651 commit1b4cc49

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3 files changed

+41
-2
lines changed

3 files changed

+41
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lines changed

‎src/backend/optimizer/util/orclauses.c

Lines changed: 10 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -178,6 +178,7 @@ extract_or_clause(RestrictInfo *or_rinfo, RelOptInfo *rel)
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{
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Node*orarg= (Node*)lfirst(lc);
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List*subclauses=NIL;
181+
Node*subclause;
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/* OR arguments should be ANDs or sub-RestrictInfos */
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if (and_clause(orarg))
@@ -226,9 +227,16 @@ extract_or_clause(RestrictInfo *or_rinfo, RelOptInfo *rel)
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227228
/*
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* OK, add subclause(s) to the result OR. If we found more than one,
229-
* we need an AND node.
230+
* we need an AND node. But if we found only one, and it is itself an
231+
* OR node, add its subclauses to the result instead; this is needed
232+
* to preserve AND/OR flatness (ie, no OR directly underneath OR).
230233
*/
231-
clauselist=lappend(clauselist,make_ands_explicit(subclauses));
234+
subclause= (Node*)make_ands_explicit(subclauses);
235+
if (or_clause(subclause))
236+
clauselist=list_concat(clauselist,
237+
list_copy(((BoolExpr*)subclause)->args));
238+
else
239+
clauselist=lappend(clauselist,subclause);
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}
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/*

‎src/test/regress/expected/join.out

Lines changed: 27 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2827,6 +2827,33 @@ select * from tenk1 a join tenk1 b on
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Index Cond: (unique2 = 3)
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(12 rows)
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2830+
explain (costs off)
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select * from tenk1 a join tenk1 b on
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(a.unique1 = 1 and b.unique1 = 2) or
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((a.unique2 = 3 or a.unique2 = 7) and b.hundred = 4);
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QUERY PLAN
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----------------------------------------------------------------------------------------------------------------------
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Nested Loop
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Join Filter: (((a.unique1 = 1) AND (b.unique1 = 2)) OR (((a.unique2 = 3) OR (a.unique2 = 7)) AND (b.hundred = 4)))
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-> Bitmap Heap Scan on tenk1 b
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Recheck Cond: ((unique1 = 2) OR (hundred = 4))
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-> BitmapOr
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-> Bitmap Index Scan on tenk1_unique1
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Index Cond: (unique1 = 2)
2843+
-> Bitmap Index Scan on tenk1_hundred
2844+
Index Cond: (hundred = 4)
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-> Materialize
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-> Bitmap Heap Scan on tenk1 a
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Recheck Cond: ((unique1 = 1) OR (unique2 = 3) OR (unique2 = 7))
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-> BitmapOr
2849+
-> Bitmap Index Scan on tenk1_unique1
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Index Cond: (unique1 = 1)
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-> Bitmap Index Scan on tenk1_unique2
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Index Cond: (unique2 = 3)
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-> Bitmap Index Scan on tenk1_unique2
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Index Cond: (unique2 = 7)
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(19 rows)
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28302857
--
28312858
-- test placement of movable quals in a parameterized join tree
28322859
--

‎src/test/regress/sql/join.sql

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -774,6 +774,10 @@ select * from tenk1 a join tenk1 b on
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explain (costs off)
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select*from tenk1 ajoin tenk1 bon
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(a.unique1=1andb.unique1=2)or (a.unique2=3andb.ten=4);
777+
explain (costs off)
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select*from tenk1 ajoin tenk1 bon
779+
(a.unique1=1andb.unique1=2)or
780+
((a.unique2=3ora.unique2=7)andb.hundred=4);
777781

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--
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-- test placement of movable quals in a parameterized join tree

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