Hi, On Sat, 2011-07-09 at 09:25 +0200, Gael Le Mignot wrote: > [...] > We are running a PostgreSQL 8.4 database, with two tables containing a > lot (> 1 million) moderatly small rows. It contains some btree indexes, > and one of the two tables contains a gin full-text index. > > We noticed that the autovacuum process tend to use a lot of memory, > bumping the postgres process near 1Gb while it's running. > Well, it could be its own memory (see maintenance_work_mem), or shared memory. So, it's hard to say if it's really an issue or not. BTW, how much memory do you have on this server? what values are used for shared_buffers and maintenance_work_mem? > I looked in the documentations, but I didn't find the information : do > you know how to estimate the memory required for the autovacuum if we > increase the number of rows ? Is it linear ? Logarithmic ? > It should use up to maintenance_work_mem. Depends on how much memory you set on this parameter. > Also, is there a way to reduce that memory usage ? Reduce maintenance_work_mem. Of course, if you do that, VACUUM could take a lot longer to execute. > Would running the > autovacuum more frequently lower its memory usage ? > Yes. -- Guillaume http://blog.guillaume.lelarge.info http://www.dalibo.com -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
