Re: Excessive PostmasterIsAlive calls slow down WAL redo

On Sat, Apr 21, 2018 at 12:25:27PM +1200, Thomas Munro wrote:
> Here's a new version, because FreeBSD's new interface changed slightly.

I have been looking at the proposed set for Linux, and the numbers are
here. By replaying 1GB worth of WAL after a pgbench run with the data
folder on a tmpfs the recovery time goes from 33s to 28s, so that's a
nice gain.

Do you have numbers with FreeBSD? I get that this would be more
difficult to set up without a GA release perhaps...

I can also see the difference in profiles by looking for
HandleStartupProcInterrupts which gets close 10% of the attention when
unpatched, and down to 0.1% when patched.

@@ -2484,6 +2484,8 @@ ClosePostmasterPorts(bool am_syslogger)
if (bonjour_sdref)
close(DNSServiceRefSockFD(bonjour_sdref));
#endif
+
+ PostmasterDeathInit();

Thomas, trying to understand here... Why this place for the signal
initialization? Wouldn't InitPostmasterChild() be a more logical place
as we'd want to have this logic caught by all other processes?
--
Michael