On Tuesday 05 December 2006 12:03, Richard Huxton wrote: > David Goodenough wrote: > > On Tuesday 05 December 2006 10:57, Bernd Helmle wrote: > >> On Tue, 5 Dec 2006 10:18:21 +0000, David Goodenough > >> > >> <david.goodenough@xxxxxxxxxxxxx> wrote: > >>> The statements issued to lock each table is:- > >>> LOCK TABLE table IN EXCLUSIVE MODE; SELECT 1 FROM table; > >> > >> So why selecting '1' for each row after locking the relation before? I > >> don't know HA-JDBC but this looks really useless. Remove the SELECT and > >> use the LOCK TABLE command within the transaction which does the sync > >> for you. > > > > I will give it a try. > > It could be that the HA-JDBC code expects some selected value back. In > which case a simple "SELECT 1" should be fine. I have to agree with > Bernd that selecting all rows and then throwing away the results strikes > me as particularly a braindead behaviour from the library, presumably it > makes some sort of sense for locking a limited number of rows. HA-JDBC only ever locks a whole table. As far as I can see it does not use the ResultSet (and JDBC large ResultSets are never a good idea), so I have asked the question on its forum why it is there. Testing with psql a simple LOCK seems pleasantly fast. David
