Thanks Toby, I will check it, and change it. regards, Carl
2011/5/30 Toby Corkindale <toby.corkind...@strategicdata.com.au> > On 28/05/11 18:42, Carl von Clausewitz wrote: > >> a few months ago, when I installed my first PostgreSQL, I have had the >> same problem. I've try to get any information about optimal memory >> config, and working, but there wasn't any "optimal memory setting >> calculator" on the internet, just some guide in the posgre documentation >> ( >> http://www.postgresql.org/docs/9.0/interactive/kernel-resources.html#SYSVIPC >> ). >> I got FreeBSD 8.2 AMD64, with 8 GB of memory (this server is just for >> PostgreSQL and a little PHP app with 2 user), and I have theese setting >> in postgresql.conf (which are not the default): >> >> [snip] > >> work_mem = 64MB# min 64kB >> maintenance_work_mem = 1024MB# min 1MB >> max_stack_depth = 64MB# min 100kB >> > > Just a warning - but be careful about setting work_mem to high values. > The actual memory used by a query can be many times the value, depending on > the complexity of your query. > > In a particular query I saw last week, we were regularly exceeding the > available memory on a server, because the query was requiring 80 times the > value of work_mem, and work_mem had been set to a high value. > > Reducing work_mem back to just 4MB reduced memory usage by a couple of > gigabytes, and had almost no effect on the execution time. (Actually, it was > marginally faster - probably because more memory was left for the operating > system's cache) > > Toby > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general >
