On 09/05/2013 02:16 PM, Bruce Momjian wrote: >> Well, the real problem with this patch is that it documents what the >> auto-tuning algorithm is; without that commitment, just saying "-1 means >> autotune" might be fine. > > OK, but I did this based on wal_buffers, which has a -1 default, calls > it auto-tuning, and explains how the default is computed.
I don't see a real problem with this. For users who have set their shared_buffers correctly, effective_cache_size should also be correct. > The problem there is that many users are told to tune shared_buffers, > but don't touch effective cache size. Having initdb set the > effective_cache_size value would not help there. Again, this is all > based on the auto-tuning of wal_buffers. Standard advice we've given in the past is 25% shared buffers, 75% effective_cache_size. Which would make EFS *3X* shared_buffers, not 4X. Maybe we're changing the conventional calculation, but I thought I'd point that out. -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
