> > I've a table with about 34601755 rows ,when I execute 'update > msg_table set > type=0;' is very very slow, cost several hours, but still not > complete? > > Why postgresql is so slowly? Is the PG MVCC problem? > > But I try it on Mysql, the same table and rows, it only cost about 340 > seconds. > > Any idea for the problem? > > > My machine config: > Memory 8G, 8 piece 15K disk , 2CPU(Quad-Core) AMD > OS: Red Hat AS4 > > My postgres.conf main parameter is following: > >
Is the "type" used in an index? Have you properly increased your number of checkpoint segments? Any warnings in in your log file about excessive checkpointing?