need a shim between postgresql and pgpool startup

[Matthew Seaman]

On 07/03/2012 20:18, Randal L. Schwartz wrote:
> [not on list... please keep me cc'ed]
> 
> Apparently, the postgresql start returns before postgresql is fully
> "warmed up".  The next thing I start is pgpool, and pgpool aborts if it
> can't connect to postgres.

Hmmm... that could be considered a bug in the postgres rc script, or
equally a bug in pgpool.

> What would the best way be to insert a 2 second delay between the two
> starts, or better yet, ensure pg was up before pgpool started, *without*
> editing the rc.d file from either of the ports (I hate having local mods
> like that).
> 
> I'm thinking of adding some sort of pgpool_startpre, or maybe a shim
> that uses requires postgresql and before pgpool.  Can I put
> pgpool_startpre() in my rc.conf file?

Create a new rc script like so, and save as pgpool_prestart in
${LOCALBASE}/etc/rc.d  Make it executable:

-------------------------------------
#!/bin/sh

# PROVIDE: pgpool_prestart
# REQUIRE: postgresql
# BEFORE: pgpool

sleep 2
-------------------------------------

Test using rcorder(8) that it would get executed between postgresql and
pgpool:

rcorder /etc/rc.d/* /usr/local/etc/rc.d/*

For extra credit, write a small routine that attempts to log into
postgres (or otherwise establish that postgres is up and doing) and
loops until it succeeds or it has reached a certain maximum number of
tries.  Make this a function called start_precommand() and use the
run_rc_command facility so it only runs if the script is given some form
of start argument.  Docco on rc script functionality is in rc.subr(8)

Also look at:
http://www.freebsd.org/doc/en/books/porters-handbook/rc-scripts.html

	Cheers,

	Matthew



-- 
Dr Matthew J Seaman MA, D.Phil.
PGP: http://www.infracaninophile.co.uk/pgpkey


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