On Tue, 2008-02-05 at 14:43 +0000, Richard Huxton wrote: > Simon Riggs wrote: > > On Tue, 2008-02-05 at 15:06 +0100, Dimitri Fontaine wrote: > >> > >> Le lundi 04 février 2008, Jignesh K. Shah a écrit : > > >>> Multiple table loads ( 1 per table) spawned via script is bit better > >>> but hits wal problems. > >> pgloader will too hit the WAL problem, but it still may have its benefits, or > >> at least we will soon (you can already if you take it from CVS) be able to > >> measure if the parallel loading at the client side is a good idea perf. wise. > > > > Should be able to reduce lock contention, but not overall WAL volume. > > In the case of a bulk upload to an empty table (or partition?) could you > not optimise the WAL away? That is, shouldn't the WAL basically be a > simple transformation of the on-disk blocks? You'd have to explicitly > sync the file(s) for the table/indexes of course, and you'd need some > work-around for WAL shipping, but it might be worth it for you chaps > with large imports. Only by locking the table, which serializes access, which then slows you down or at least restricts other options. Plus if you use pg_loader then you'll find only the first few rows optimized and all the rest not. -- Simon Riggs 2ndQuadrant http://www.2ndQuadrant.com ---------------------------(end of broadcast)--------------------------- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate
