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Allow ORDER BY, LIMIT in sub-selects. Fix most (not all) cases where
the grammar did not allow redundant parentheses around sub-selects. Distinguish LIMIT ALL from LIMIT 0; make the latter behave as one would expect.
1 parent 66436e6 commit 11f7b29

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8 files changed

+388
-218
lines changed

8 files changed

+388
-218
lines changed

‎src/backend/executor/nodeLimit.c

Lines changed: 4 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/executor/nodeLimit.c,v 1.1 2000/10/26 21:35:15 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/executor/nodeLimit.c,v 1.2 2000/11/05 00:15:52 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -188,17 +188,11 @@ recompute_limits(Limit *node)
188188
econtext,
189189
&isNull,
190190
NULL));
191-
/* Interpret NULL count as no count */
191+
/* Interpret NULL count as no count (LIMIT ALL) */
192192
if (isNull)
193193
limitstate->noCount = true;
194-
else
195-
{
196-
/* Currently, LIMIT 0 is specified as meaning no limit.
197-
* I think this is pretty bogus, but ...
198-
*/
199-
if (limitstate->count <= 0)
200-
limitstate->noCount = true;
201-
}
194+
else if (limitstate->count < 0)
195+
limitstate->count = 0;
202196
}
203197
else
204198
{

‎src/backend/nodes/copyfuncs.c

Lines changed: 6 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -15,7 +15,7 @@
1515
* Portions Copyright (c) 1994, Regents of the University of California
1616
*
1717
* IDENTIFICATION
18-
* $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.128 2000/10/31 10:22:10 petere Exp $
18+
* $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.129 2000/11/05 00:15:52 tgl Exp $
1919
*
2020
*-------------------------------------------------------------------------
2121
*/
@@ -1826,6 +1826,7 @@ _copySelectStmt(SelectStmt *from)
18261826
Node_Copy(from, newnode, distinctClause);
18271827
if (from->into)
18281828
newnode->into = pstrdup(from->into);
1829+
newnode->istemp = from->istemp;
18291830
Node_Copy(from, newnode, targetList);
18301831
Node_Copy(from, newnode, fromClause);
18311832
Node_Copy(from, newnode, whereClause);
@@ -1835,10 +1836,13 @@ _copySelectStmt(SelectStmt *from)
18351836
if (from->portalname)
18361837
newnode->portalname = pstrdup(from->portalname);
18371838
newnode->binary = from->binary;
1838-
newnode->istemp = from->istemp;
18391839
Node_Copy(from, newnode, limitOffset);
18401840
Node_Copy(from, newnode, limitCount);
18411841
Node_Copy(from, newnode, forUpdate);
1842+
newnode->op = from->op;
1843+
newnode->all = from->all;
1844+
Node_Copy(from, newnode, larg);
1845+
Node_Copy(from, newnode, rarg);
18421846

18431847
return newnode;
18441848
}

‎src/backend/nodes/equalfuncs.c

Lines changed: 11 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -20,7 +20,7 @@
2020
* Portions Copyright (c) 1994, Regents of the University of California
2121
*
2222
* IDENTIFICATION
23-
* $Header: /cvsroot/pgsql/src/backend/nodes/equalfuncs.c,v 1.78 2000/10/31 10:22:10 petere Exp $
23+
* $Header: /cvsroot/pgsql/src/backend/nodes/equalfuncs.c,v 1.79 2000/11/05 00:15:52 tgl Exp $
2424
*
2525
*-------------------------------------------------------------------------
2626
*/
@@ -686,6 +686,8 @@ _equalSelectStmt(SelectStmt *a, SelectStmt *b)
686686
return false;
687687
if (!equalstr(a->into, b->into))
688688
return false;
689+
if (a->istemp != b->istemp)
690+
return false;
689691
if (!equal(a->targetList, b->targetList))
690692
return false;
691693
if (!equal(a->fromClause, b->fromClause))
@@ -702,14 +704,20 @@ _equalSelectStmt(SelectStmt *a, SelectStmt *b)
702704
return false;
703705
if (a->binary != b->binary)
704706
return false;
705-
if (a->istemp != b->istemp)
706-
return false;
707707
if (!equal(a->limitOffset, b->limitOffset))
708708
return false;
709709
if (!equal(a->limitCount, b->limitCount))
710710
return false;
711711
if (!equal(a->forUpdate, b->forUpdate))
712712
return false;
713+
if (a->op != b->op)
714+
return false;
715+
if (a->all != b->all)
716+
return false;
717+
if (!equal(a->larg, b->larg))
718+
return false;
719+
if (!equal(a->rarg, b->rarg))
720+
return false;
713721

714722
return true;
715723
}

‎src/backend/optimizer/plan/planner.c

Lines changed: 12 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.93 2000/10/26 21:36:09 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.94 2000/11/05 00:15:53 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -809,25 +809,26 @@ union_planner(Query *parse,
809809
if (IsA(parse->limitCount, Const))
810810
{
811811
Const *limitc = (Const *) parse->limitCount;
812-
int count = (int) (limitc->constvalue);
812+
int32 count = DatumGetInt32(limitc->constvalue);
813813

814814
/*
815-
* The constant can legally be either 0 ("ALL") or a
816-
* positive integer. If it is not ALL, we also need
817-
* to consider the OFFSET part of LIMIT.
815+
* A NULL-constant LIMIT represents "LIMIT ALL",
816+
* which we treat the same as no limit (ie,
817+
* expect to retrieve all the tuples).
818818
*/
819-
if (count > 0)
819+
if (!limitc->constisnull && count > 0)
820820
{
821821
tuple_fraction = (double) count;
822+
/* We must also consider the OFFSET, if present */
822823
if (parse->limitOffset != NULL)
823824
{
824825
if (IsA(parse->limitOffset, Const))
825826
{
826-
int offset;
827+
int32 offset;
827828

828829
limitc = (Const *) parse->limitOffset;
829-
offset = (int) (limitc->constvalue);
830-
if (offset > 0)
830+
offset = DatumGetInt32(limitc->constvalue);
831+
if (!limitc->constisnull && offset > 0)
831832
tuple_fraction += (double) offset;
832833
}
833834
else
@@ -850,14 +851,14 @@ union_planner(Query *parse,
850851
}
851852

852853
/*
853-
* Check for a retrieve-into-portal, ie DECLARE CURSOR.
854+
* If no LIMIT, check for retrieve-into-portal, ie DECLARE CURSOR.
854855
*
855856
* We have no real idea how many tuples the user will ultimately
856857
* FETCH from a cursor, but it seems a good bet that he
857858
* doesn't want 'em all. Optimize for 10% retrieval (you
858859
* gotta better number?)
859860
*/
860-
if (parse->isPortal)
861+
else if (parse->isPortal)
861862
tuple_fraction = 0.10;
862863
}
863864

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