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Fix LIMIT/OFFSET for null limit values. This worked before 8.2 but was broken

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by the change to make limit values int8 instead of int4.  (Specifically, you
can do DatumGetInt32 safely on a null value, but not DatumGetInt64.)  Per
bug #2803 from Greg Johnson.
This commit is contained in:
Tom Lane 2006-12-03 21:40:13 +00:00
parent dca4d77798
commit 7f676624f6
1 changed files with 26 additions and 16 deletions
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32
src/backend/executor/nodeLimit.c
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@ -8,7 +8,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/nodeLimit.c,v 1.27 2006/07/26 19:31:50 tgl Exp $ * $PostgreSQL: pgsql/src/backend/executor/nodeLimit.c,v 1.27.2.1 2006/12/03 21:40:13 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -225,21 +225,25 @@ static void
recompute_limits(LimitState *node) recompute_limits(LimitState *node)
{ {
ExprContext *econtext = node->ps.ps_ExprContext; ExprContext *econtext = node->ps.ps_ExprContext;
Datum val;
bool isNull; bool isNull;
if (node->limitOffset) if (node->limitOffset)
{ {
node->offset = val = ExecEvalExprSwitchContext(node->limitOffset,
DatumGetInt64(ExecEvalExprSwitchContext(node->limitOffset,
econtext, econtext,
&isNull, &isNull,
NULL)); NULL);
/* Interpret NULL offset as no offset */ /* Interpret NULL offset as no offset */
if (isNull) if (isNull)
node->offset = 0; node->offset = 0;
else if (node->offset < 0) else
{
node->offset = DatumGetInt64(val);
if (node->offset < 0)
node->offset = 0; node->offset = 0;
} }
}
else else
{ {
/* No OFFSET supplied */ /* No OFFSET supplied */
@ -248,17 +252,23 @@ recompute_limits(LimitState *node)
if (node->limitCount) if (node->limitCount)
{ {
node->noCount = false; val = ExecEvalExprSwitchContext(node->limitCount,
node->count =
DatumGetInt64(ExecEvalExprSwitchContext(node->limitCount,
econtext, econtext,
&isNull, &isNull,
NULL)); NULL);
/* Interpret NULL count as no count (LIMIT ALL) */ /* Interpret NULL count as no count (LIMIT ALL) */
if (isNull) if (isNull)
node->noCount = true; {
else if (node->count < 0)
node->count = 0; node->count = 0;
node->noCount = true;
}
else
{
node->count = DatumGetInt64(val);
if (node->count < 0)
node->count = 0;
node->noCount = false;
}
} }
else else
{ {