Re: what are the ways to avoid --- "ERROR: EXECUTE of SELECT ... INTO is not implemented yet"

From: Shantanu <shantanu(dot)gg(at)gmail(dot)com>
To: tomas(at)tuxteam(dot)de
Cc: pgsql-bugs(at)postgresql(dot)org
Subject: Re: what are the ways to avoid --- "ERROR: EXECUTE of SELECT ... INTO is not implemented yet"
Date: 2008-05-31 17:21:35
Message-ID: 97d558890805311021h29549564p8c67bba0ab853731@mail.gmail.com
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Here is my real use case

1) We have nornal SELECT ...INTO calls in the procedure calls
2) However we landed ourselves with the following problem
http://www.postgresql.org/docs/faqs.FAQ.html#item4.19

<snip>
4.19) Why do I get "relation with OID ##### does not exist" errors when
accessing temporary tables in PL/PgSQL functions?

In PostgreSQL versions < 8.3, PL/PgSQL caches function scripts, and an
unfortunate side effect is that if a PL/PgSQL function accesses a temporary
table, and that table is later dropped and recreated, and the function
called again, the function will fail because the cached function contents
still point to the old temporary table. The solution is to use EXECUTE for
temporary table access in PL/PgSQL. This will cause the query to be reparsed
every time.

This problem does not occur in PostgreSQL 8.3 and later.
</snip>

3) So the solution we are trying to implement is the EXECUTE command one.

This is causing the SELECT ...INTO problem

Upgrade is not an option :(

Currently the only available solution is
Use a temporary table where we write the local variable and make it read
from the table .

Any alternatives ?

~
Shantanu

On Sat, May 31, 2008 at 8:38 AM, <tomas(at)tuxteam(dot)de> wrote:

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> On Fri, May 30, 2008 at 09:57:49PM +0530, Shantanu wrote:
> > Hello experts,
> >
> >
> > I am facing this error.
> >
> > mydb=> select version();
> > version
> >
> >
> --------------------------------------------------------------------------------
> >
> > PostgreSQL 8.1.9
> >
> > (1 row)
> >
> > mydb=> \i /tmp/test.sql
> > CREATE FUNCTION
> > mydb=> select sp_test();
> > ERROR: EXECUTE of SELECT ... INTO is not implemented yet
> > CONTEXT: PL/pgSQL function "sp_test" line 4 at execute statement
> >
> >
> > mydb=>
> > [1]+ Stopped su - dbu
> > mymachine<root># cat /tmp/test.sql
> > create or replace function sp_test() RETURNS void as $$
> > declare
> > l_var timestamp;
> > begin
> > execute 'SELECT NOW() INTO l_var';
> ^^^^^^^^^^^^^^^^^^
>
> Why do you need execute '...' at all? Why not directly do instead
>
> SELECT NOW() into l_var;
>
> What is your "real" use case?
>
> Note that if you really need the dynamic command, you might put its
> result int a variable, like so:
>
> EXECUTE 'SELECT NOW()' INTO l_var;
>
> ...but if we don't know what you are trying to achieve, it's difficult
> to provide meaningful recommendations.
>
> Regards
> - -- tomás
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