Horton

Re: [PATCH] pg_isready (was: [WIP] pg_ping utility)

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Phil Sorber <phil@omniti.com>
Cc: Bruce Momjian <bruce@momjian.us>, Robert Haas <robertmhaas@gmail.com>, Craig Ringer <craig@2ndquadrant.com>, Michael Paquier <michael.paquier@gmail.com>, Erik Rijkers <er@xs4all.nl>, Alvaro Herrera <alvherre@2ndquadrant.com>, Dimitri Fontaine <dimitri@2ndquadrant.fr>, Peter Eisentraut <peter_e@gmx.net>, PostgreSQL-development Hackers <pgsql-hackers@postgresql.org>
Date: 2013-01-23T23:07:51Z
Lists: pgsql-hackers 
Phil Sorber <phil@omniti.com> writes:
> On Wed, Jan 23, 2013 at 1:58 PM, Bruce Momjian <bruce@momjian.us> wrote:
>> On Wed, Jan 23, 2013 at 12:27:45PM -0500, Tom Lane wrote:
>>> +1 for default timeout --- if this isn't like "ping" where you are
>>> expecting to run indefinitely, I can't see that it's a good idea for it
>>> to sit very long by default, in any circumstance.

>> FYI, the pg_ctl -w (wait) default is 60 seconds:

> Great. That is what I came to on my own as well. Figured that might be
> a sticking point, but as there is precedent, I'm happy with it.

I'm not sure that's a relevant precedent at all.  What that number is
is the time that pg_ctl will wait around for the postmaster to start or
stop before reporting a problem --- and in either case, a significant
delay (multiple seconds) is not surprising, because of crash-recovery
work, shutdown checkpointing, etc.  For pg_isready, you'd expect to get
a response more or less instantly, wouldn't you?  Personally, I'd decide
that pg_isready is broken if it didn't give me an answer in a couple of
seconds, much less a minute.

What I had in mind was a default timeout of maybe 3 or 4 seconds...

			regards, tom lane