Re: wal_buffers

On Mon, Feb 20, 2012 at 3:59 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>> There is no existing statistics view suitable to include such information.
>> What about defining pg_stat_xlog or something?
>
> Perhaps pg_stat_perf so we don't need to find a new home every time.
>
> Thinking about it, I think renaming pg_stat_bgwriter would make more sense.

When we created pg_stat_reset_shared(text), we seemed to be
contemplating the idea of multiple sets of shared counters identified
by names -- bgwriter for the background writer, and maybe other things
for other subsystems. So we'd have to think about how to adjust that.
I do agree with you that it seems a shame to invent a whole new view
for one counter...

Another thought is that I'm not sure it makes sense to run this
through the stats system at all. We could regard it as a shared
memory counter protected by one of the LWLocks involved, which would
probably be quite a bit cheaper - just one machine instruction to
increment it at need.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company