On Sat, Nov 26, 2011 at 10:10 AM, Robert Haas <robertmh...@gmail.com> wrote: > On Fri, Nov 25, 2011 at 11:39 AM, Alvaro Herrera > <alvhe...@commandprompt.com> wrote: >> I'm going to push this now anyway, thanks. > > This patch adds a count of the number of buffers dirtied to VACUUM, > but it strikes me that it would be useful to add similar tracking to > pgBufferUsage. Attached is a patch for that. You can see the new > counters through pg_stat_statements or with EXPLAIN (ANALYZE, > BUFFERS). This is useful because the number of buffers that a query > *writes* doesn't necessarily have much to do with anything - it may > end up writing buffers dirtied by other queries while being read-only > itself, or conversely it may not write anything at all even though it > dirties quite a bit. > > Thoughts? Comments? Objections?
Here are review comments: The document about EXPLAIN needs to be updated. You forgot to add the long-integer-valued property of shared/local_blks_dirtied. So when I ran EXPLAIN and used json as a format, no information about blks_dirtied was reported. Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
