Re: ECPG regression with DECLARE STATEMENT support - Mailing list pgsql-hackers

From Michael Meskes
Subject Re: ECPG regression with DECLARE STATEMENT support
Date
Msg-id 30663ed406b3fcc2288b2fe8b57f9c4e8389b3ec.camel@postgresql.org
Whole thread Raw
In response to ECPG regression with DECLARE STATEMENT support  (Rushabh Lathia <rushabh.lathia@gmail.com>)
Responses Re: ECPG regression with DECLARE STATEMENT support
List pgsql-hackers
Hi,

> Commit bd7c95f0c1a38becffceb3ea7234d57167f6d4bf add DECLARE
> STATEMENT support to ECPG.  This introduced the new rule
> for EXEC SQL CLOSE cur and with that it gets transformed into
> ECPGclose().
> 
> Now prior to the above commit, someone can declare the
> cursor in the SQL statement and "CLOSE cur_name" can be
> also, execute as a normal statement.

That still works, the difference in your test case is that the DECLARE
statement is prepared.

> Example:
> 
> EXEC SQL PREPARE cur_query FROM "DECLARE cur1 CURSOR WITH HOLD FOR
> SELECT count(*) FROM pg_class";
> EXEC SQL PREPARE fetch_stmt FROM "FETCH next FROM cur1";
> EXEC SQL EXECUTE cur_query;
> EXEC SQL EXECUTE fetch_stmt INTO :c;
> EXEC SQL CLOSE cur1;
> 
> With commit bd7c95f0c1, "EXEC SQL CLOSE cur1" will fail
> and throw an error "sqlcode -245 The cursor is invalid".
> 
> I think the problem here is ECPGclose(), tries to find the
> cursor into "connection->cursor_stmts" and if it doesn't
> find it there, just throws an error.   Maybe require fix
> into ECPGclose() - rather than throwing an error continue
> executing statement "CLOSE cur_name" with ecpg_do().

The problem as I see it is that the cursor is known to the backend but
not the library. Takaheshi-san, Hayato-san, any idea how to improve the
situation to not error out on statements that used to work?

Michael
-- 
Michael Meskes
Michael at Fam-Meskes dot De, Michael at Meskes dot (De|Com|Net|Org)
Meskes at (Debian|Postgresql) dot Org
Jabber: michael at xmpp dot meskes dot org
VfL Borussia! Força Barça! SF 49ers! Use Debian GNU/Linux, PostgreSQL



pgsql-hackers by date:

Previous
From: David Rowley
Date:
Subject: Re: Inheriting table AMs for partitioned tables
Next
From: John Naylor
Date:
Subject: Re: WIP: Avoid creation of the free space map for small tables