> I see - thanks very much. I created an index for column 'oid' which I
> was using in a WHERE. So rule of thumb- create an index for column(s)
> which I use in WHERE queries.
So to speak. They can also sometimes assist in sorting. The OID column
is special. I suggest adding a unique index to that column. In
postgresql it is _possible_ for the oid counter to wraparound, hence if
you rely on oids (not necessarily a good idea), it's best to put a
unique index on the oid column.
I _strongly_ suggest that you read this:
http://www.postgresql.org/docs/7.4/static/indexes.html
Chris