Bruce Momjian escribió: > > So, are you saying you like 4x now? > > Here is an arugment for 3x. First, using the documented 25% of RAM, 3x > puts our effective_cache_size as 75% of RAM, giving us no room for > kernel, backend memory, and work_mem usage. If anything it should be > lower than 3x, not higher.
The other argument I see for the 3x value is that it is a compromise. People with really large servers will want to increase it; people with very small servers will want to reduce it. > Finally, for those who like the idea of 4x, you can think of > shared_buffers (1x) + effective_cache_size (3x) as totalling 4x. This part of your argument doesn't work really, because AFAIR the effective_cache_size value ought to consider that shared_buffers is part of it (so e_c_s is shared_buffers + kernel cache). So if you're seeing the 4x as e_c_s + s_b, you would be counting s_b twice. -- Álvaro Herrera http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
