Re: Changing sequence cache

On Mon, Mar 04, 2002 at 06:16:33PM -0500, Tom Lane wrote:
> Matthew Price  writes:
> > I already have a sequence named customers_custid_seq
> > I would like to increase the cache setting some.  How can i alter the cache after the sequence has already been created?
> 
> You can't, but there's no reason you shouldn't drop and recreate the
> sequence.

I had to do something very similar to this once, on a running production 
database.  I believe that I used something like this:

DROP FUNCTION my_modify_sequence();
CREATE FUNCTION my_modify_sequence() RETURNS integer AS '
DECLARE sequence_value INTEGER; create_string TEXT := \'CREATE SEQUENCE foo_foo_id_seq START \';
BEGIN SELECT INTO sequence_value nextval(\'foo_foo_id_seq\'); RAISE NOTICE \'Sequence value is currently %\', sequence_value; EXECUTE \'DROP SEQUENCE foo_foo_id_seq\'; EXECUTE create_string || sequence_value; RETURN sequence_value;
END;
' LANGUAGE 'plpgsql';

-- do the deed
BEGIN;
LOCK TABLE foo IN ACCESS EXCLUSIVE MODE;
SELECT my_modify_sequence();
COMMIT;

-- 
Andrew G. Hammond  mailto:drew@xyzzy.dhs.org  http://xyzzy.dhs.org/~drew/
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"To blow recursion you must first blow recur" -- me