[pgpool-general: 270] ERROR: cannot execute SELECT FOR UPDATE in a read-only transaction

[Martin Kotys]

Hey,

We've installed pgPoolII on our servers and would like to switch over 
our application to pgpool. When we did it, we got the following error:

ERROR: DBD::Pg::db selectrow_array failed: ERROR:  cannot execute SELECT 
FOR UPDATE in a read-only transaction
CONTEXT:  SQL statement "SELECT id::varchar || '-' || actorderid::varchar
                                   FROM shop WHERE id = $1 FOR UPDATE"
PL/pgSQL function "nextorderid" line 5 at SQL statement [for Statement 
"SELECT nextorderid(2)"]

Nextorderid is a stored procedure which returns an order ID. Strange 
thing is that it sometimes work and sometimes not.

I assume that the problem is that if the query is sent to master server, 
all is OK, but if the query is sent to slave it fails.
The same will probably happen with select nextval(), begin end, and so on.

Have you experienced similar issue by any chance? Don't you know how to 
solve that issue?

Thanks.
Martin