| From: | Dilip Kumar <dilipbalaut(at)gmail(dot)com> |
|---|---|
| To: | Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com> |
| Cc: | Petr Jelinek <petr(at)2ndquadrant(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Andres Freund <andres(at)2ndquadrant(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Relation extension scalability |
| Date: | 2016-03-14 02:29:51 |
| Message-ID: | CAFiTN-sZ=XP1=+OSNwVVMDQxw=ue6=51c-0XF8h1Ftr9HdzEcw@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Mon, Mar 14, 2016 at 5:02 AM, Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com> wrote:
> Well, 16MB is 2K pages, which is what you'd get if 100 connections were
> all blocked and we're doing 20 pages per waiter. That seems like a really
> extreme scenario, so maybe 4MB is a good compromise. That's unlikely to be
> hit in most cases, unlikely to put a ton of stress on IO, even with
> magnetic media (assuming the whole 4MB is queued to write in one shot...).
> 4MB would still reduce the number of locks by 500x.
In my performance results given up thread, we are getting max performance
at 32 clients, means at a time we are extending 32*20 ~= max (600) pages at
a time. So now with 4MB limit (max 512 pages) Results will looks similar.
So we need to take a decision whether 4MB is good limit, should I change it
?
--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com
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