Re: Overhauling GUCS

Tom Lane wrote:
> Josh Berkus <josh@agliodbs.com> writes:
>> Oh, and wal_buffers, the default for which we should just change if it
>> weren't for SHMMAX.
> 
> Uh, why?  On a workload of mostly small transactions, what value is
> there in lots of wal_buffers?

None. But there's also little to no harm in having a higher setting; at 
worst you waste a few megabytes of memory. Besides, most databases are 
initialized from some outside source in the beginning, and data loading 
does benefit from a higher wal_buffers setting.

Ideally, of course, there would be no wal_buffers setting, and WAL 
buffers would be allocated from shared_buffers pool on demand...

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com