Re: explain doesn't work with execute using

"Pavel Stehule" <pavel(dot)stehule(at)gmail(dot)com> writes:
> I found following bug - using explain in stored procedures like:
> ...
> produce wrong result. Real plan is correct, etc variables are
> substituted. Bud this explain show variables.

This seems to be correctable with a one-line patch: make SPI_cursor_open
set the CONST flag on parameters it puts into the portal (attached).
I'm not entirely sure if it's a good idea or not --- comments?

regards, tom lane

Index: src/backend/executor/spi.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/executor/spi.c,v
retrieving revision 1.195
diff -c -r1.195 spi.c
*** src/backend/executor/spi.c 12 May 2008 20:02:00 -0000 1.195
--- src/backend/executor/spi.c 1 Jun 2008 15:33:13 -0000
***************
*** 997,1003 ****
ParamExternData *prm = &paramLI->params[k];

prm->ptype = plan->argtypes[k];
! prm->pflags = 0;
prm->isnull = (Nulls && Nulls[k] == 'n');
if (prm->isnull)
{
--- 997,1010 ----
ParamExternData *prm = &paramLI->params[k];

prm->ptype = plan->argtypes[k];
! /*
! * We mark the parameters as const. This has no effect for simple
! * execution of a plan, but if more planning happens within the
! * portal (eg via EXPLAIN), the effect will be to treat the
! * parameters as constants. This is good and correct as long as
! * no plan generated inside the portal is used outside it.
! */
! prm->pflags = PARAM_FLAG_CONST;
prm->isnull = (Nulls && Nulls[k] == 'n');
if (prm->isnull)
{