Re: understanding postgres issues/bottlenecks

At 03:28 PM 1/8/2009, Merlin Moncure wrote:
>On Thu, Jan 8, 2009 at 9:42 AM, Stefano Nichele
><stefano(dot)nichele(at)gmail(dot)com> wrote:
> > Merlin Moncure wrote:
> >> IIRC that's the 'perc 6ir' card...no write caching. You are getting
> >> killed with syncs. If you can restart the database, you can test with
> >> fsync=off comparing load to confirm this. (another way is to compare
> >> select only vs regular transactions on pgbench).
> >
> > I'll try next Saturday.
> >
>
>just be aware of the danger . hard reset (power off) class of failure
>when fsync = off means you are loading from backups.
>
>merlin
That's what redundant power conditioning UPS's are supposed to help prevent ;-)

Merlin is of course absolutely correct that you are taking a bigger
risk if you turn fsync off.

I would not recommend fysnc = off if you do not have other safety
measures in place to protect against data loss because of a power event..
(At least for most DB applications.)

...and of course, those lucky few with bigger budgets can use SSD's
and not care what fsync is set to.

Ron