| From: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> |
|---|---|
| To: | Andres Freund <andres(at)anarazel(dot)de> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Excessive PostmasterIsAlive calls slow down WAL redo |
| Date: | 2018-04-10 01:57:23 |
| Message-ID: | 20180410015723.3fxcaj2x23w26oox@alvherre.pgsql |
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| Thread: | |
| Lists: | pgsql-hackers |
Andres Freund wrote:
>
> On April 9, 2018 6:31:07 PM PDT, Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> wrote:
> >Would it work to use this second pipe, to which each child writes a
> >byte that postmaster never reads, and then rely on SIGPIPE when
> >postmaster dies? Then we never need to do a syscall.
>
> I'm not following, could you expand on what you're suggesting? Note
> that you do not get SIGPIPE for already buffered writes. Which
> syscall can we avoid?
Ah. I was thinking we'd get SIGPIPE from the byte sent at the start, as
soon as the kernel saw that postmaster abandoned the fd by dying.
Scratch that then.
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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