On Sat, Dec 18, 2010 at 1:00 AM, Robert Haas <robertmh...@gmail.com> wrote: > On Fri, Dec 17, 2010 at 10:27 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> Robert Haas <robertmh...@gmail.com> writes: >>> I think the attached might be a little tidier. Thoughts? >> >> I'm not really thrilled at the idea of calling >> IsPostmasterChildWalSender for every child whether or not it will have >> any impact on the decision. That involves touching shared memory which >> can be rather expensive (see previous discussions about shared cache >> lines and so forth). > > The existing code already does that, unless I'm missing something. We > could improve on my proposed patch a bit by doing the is_autovacuum > test first and the walsender test second. I'm not sure how to improve > on it beyond that.
How about doing target != ALL test at the head for the most common case (target == ALL)? I added that test into your patch and changed it so that the is_autovacuum test is done first. Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center
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