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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 21:40:07 +00:00
parent 75330c3205
commit 406d028a9b
1 changed files with 26 additions and 16 deletions
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42
src/backend/executor/nodeLimit.c
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@ -8,7 +8,7 @@
*
*
* 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 1.28 2006/12/03 21:40:07 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -225,20 +225,24 @@ static void
recompute_limits(LimitState *node)
{
ExprContext *econtext = node->ps.ps_ExprContext;
Datum val;
bool isNull;
if (node->limitOffset)
{
node->offset =
DatumGetInt64(ExecEvalExprSwitchContext(node->limitOffset,
econtext,
&isNull,
NULL));
val = ExecEvalExprSwitchContext(node->limitOffset,
econtext,
&isNull,
NULL);
/* Interpret NULL offset as no offset */
if (isNull)
node->offset = 0;
else if (node->offset < 0)
node->offset = 0;
else
{
node->offset = DatumGetInt64(val);
if (node->offset < 0)
node->offset = 0;
}
}
else
{
@ -248,17 +252,23 @@ recompute_limits(LimitState *node)
if (node->limitCount)
{
node->noCount = false;
node->count =
DatumGetInt64(ExecEvalExprSwitchContext(node->limitCount,
econtext,
&isNull,
NULL));
val = ExecEvalExprSwitchContext(node->limitCount,
econtext,
&isNull,
NULL);
/* Interpret NULL count as no count (LIMIT ALL) */
if (isNull)
node->noCount = true;
else if (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
{