Startup scripts - Use -m fast or smart?

Glyn Astill wrote:

I've just changed my startup scripts to use the linux one supplied in
contrib.

I noticed this uses the "-m fast" argument for start and stop.

Before I setup the scripts I was using "-m smart" to make sure all
queries were finished before shutting dowm on all but my WAL slave.

I was going to change these to -m smart just to be safe, however I
just wanted to check if there was any reason not to do this?

If you have "pg_ctl stop -m smart" in your shutdown script, this
will prevent your host from shutting down as long as somebody is still
connected to the database, even if the connections are idle.

This is most likely *not* what you want.

-m fast is the correct thing for server shutdown. It will do no damage
as all active transactions will be rolled back.

If there are database transactions that you do not want to interrupt,
the best approach is not to shutdown the database server.

Yours,
Laurenz Albe

Thanks Laurenz, that's a good point, I shall leave them as is.

Glyn

--- Albe Laurenz <laurenz.albe@wien.gv.at> wrote:

Glyn Astill wrote:

I've just changed my startup scripts to use the linux one

supplied in

contrib.

I noticed this uses the "-m fast" argument for start and stop.

Before I setup the scripts I was using "-m smart" to make sure

all

queries were finished before shutting dowm on all but my WAL

slave.

I was going to change these to -m smart just to be safe, however

I

just wanted to check if there was any reason not to do this?

If you have "pg_ctl stop -m smart" in your shutdown script, this
will prevent your host from shutting down as long as somebody is
still
connected to the database, even if the connections are idle.

This is most likely *not* what you want.

-m fast is the correct thing for server shutdown. It will do no
damage
as all active transactions will be rolled back.

If there are database transactions that you do not want to
interrupt,
the best approach is not to shutdown the database server.

Yours,
Laurenz Albe

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