Subject: Re: New trigger option of pg_standby
From: Simon Riggs <simon@2ndQuadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Peter Eisentraut <peter_e@gmx.net>,
	Guillaume Smet <guillaume.smet@gmail.com>,
	Fujii Masao <masao.fujii@gmail.com>,
	Kevin Grittner <Kevin.Grittner@wicourts.gov>,
	pgsql-hackers <pgsql-hackers@postgresql.org>
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Date: Fri, 27 Mar 2009 14:36:36 +0000
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On Fri, 2009-03-27 at 10:25 -0400, Tom Lane wrote:
> Peter Eisentraut <peter_e@gmx.net> writes:
> > Simon Riggs wrote:
> >> If we go with this, I would suggest we make *neither* the default by
> >> removing -t, and adopting two new options: something like -f == fast
> >> failover, -p == patient failover.
> 
> > -m smart|fast|immediate :-)
> 
> +1 for using a "-m something" type of syntax instead of having to try to
> pick single-letter switches that are mnemonic for the different cases.
> But -1 to those particular mode names --- I think it will invite
> confusion with pg_ctl's behavior.

The choice is between

* one parameter with the option being given as text within trigger file

* two parameters naming different types of trigger file

I don't mind which, as long as it is one of those two, unless there is a
third way to specify things so that user has control at failover time. A
single -m option would hardcode that decision ahead of time, which is
undesirable behaviour, hence the additional complexity being discussed.

-- 
 Simon Riggs           www.2ndQuadrant.com
 PostgreSQL Training, Services and Support