Re: Documentation Update: Document pg_start_backup checkpoint behavior

Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> writes:
> Tom Lane wrote:
>> The solution Heikki is proposing is to let the user choose immediate
>> or slow checkpoint. I agree that there's not much point in the latter
>> if you are using something dumb like tar to take the filesystem backup,
>> but maybe the user has something smarter that won't cause such a big
>> I/O storm.

> If the user is knowledgeable enough to use a smarter backup tool, he's
> probably knowledgeable enough to put pg_start_backup('foo', true)
> instead of just pg_start_backup('foo') in his scripts. But a new user
> who's just playing around and making his first backup, probably using
> tar, isn't.

It's not actually that difficult to have a tar backup be rate-limited.
If you're dumping the tar output onto a tape drive, or sending it across
a network, or indeed doing anything except dropping it onto another
local disk drive, you are going to find that tar is not saturating
your disk.

regards, tom lane