Hey Joe, You can wrap the given query in the PL/pgSQL function, catch the exception and return NULL if it occurs. Please see http://www.postgresql.org/docs/9.0/static/plpgsql-control-structures.html#PLPGSQL-ERROR-TRAPPING
2010/12/9 Joe Carr <joe.c...@gmail.com> > Hello, > I have a simple table-based queue system, and I'd looking for some advice > on improving my dequeue function. it boils down to: > > SELECT id > FROM queue > WHERE <whereclause> > FOR UPDATE NOWAIT; > > which works well, in that no item gets dequeued more that once. The issue, > however is that when a contention occurs, the error "could not obtain lock > on row in relation" is raised. > > Is there a way that I can rewrite this so that when a contention occurs, > there is no error? I would like the "winning" process to lock the row, and > the "losing" process to select null rather than raise the rowlock error. > > thanks beforehand for any help! > -- // Dmitriy.
