Oliver Jowett <oli...@opencloud.com> writes:

OK thanks, now I think I got it: it seems like the JDBC API does not assume you need parameter types to plan the query.

Connection.preparedStatement()

* If the driver supports precompilation, * the method <code>prepareStatement</code> will send * the statement to the database for precompilation.

No word about parameter types. If you do not need the datatypes, then you can send/plan the query way earlier (not "lazy"), at PreparedStatement object construction time.

I should have noticed this issue from here <http://www.postgresql.org/docs/8.1/interactive/sql-prepare.html> Looks like we have an API mismatch here.

Is this parameter types issue specific to PostgreSQL, or is just the JDBC API badly designed on this point?

Another approach could be for the server to infer the types from the query string?

If not 100% reliably, then in an optimistic way?

Could this be compatible with any setMaxRows() optimization? I guess yes, provided the maxRows parameter is considered in preparedstatement matching, just like datatypes seem to be... Maybe this is already the case for non-JDBC PREPARE + LIMIT?

Thanks again for all these answers.