Horton

Re: Excessive PostmasterIsAlive calls slow down WAL redo

Alvaro Herrera <alvherre@alvh.no-ip.org>

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Andres Freund <andres@anarazel.de>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Heikki Linnakangas <hlinnaka@iki.fi>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2018-04-10T01:31:07Z
Lists: pgsql-hackers 
Andres Freund wrote:

> Another approach, that's simpler to implement, is to simply have a
> second selfpipe, just for WL_POSTMASTER_DEATH.

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.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Poll postmaster less frequently in recovery.

  2. Use signals for postmaster death on FreeBSD.

  3. Use signals for postmaster death on Linux.

  4. Introduce a pipe between postmaster and each backend, which can be used to