What about the setFetchSize method? My impression is that using
setFetchSize along with setMaxRows would do the trick on the back end as
it resulted in the cursor mechanism that didn't retrieve the complete
result set. Is that not the case in PG 8.1 (at least with the few
caveats listed at http://jdbc.postgresql.org/documentation/81/query.html)?
David
It's not a bug. setMaxRows() is essentially a hint, there's certainly
no requirement that the driver will go off and add LIMIT clauses to
your query, the minimal implementation won't change query execution at
all and will just limit rows coming back out of the ResultSet.. It
might be nice to add LIMIT but that would require the driver to parse
query strings which gets very complicated and isn't going to catch all
the cases anyway. You'll be getting at least some improvement with the
existing driver because the whole resultset isn't being transferred
and processed, even if the plan is still assuming you will grab all
the data.
If your queries need a LIMIT clause to get decent performance then
your safest bet is to add a LIMIT clause yourself. You can keep the
setMaxRows() as well if you like..
24 messages in org.postgresql.pgsql-jdbcRe: Limit vs setMaxRows issue
