On Fri, 2005-08-05 at 14:28, D Kavan wrote:
> Hi,
>
> It's taken 4 hours so far to dump a 3.5 GB database on a local disk.
> How can I increase performance?
>
> We have the work memory & effective cach size are set to 16 MB. Our
> maintenance_work_memory is set to 256 MB. Thanks for any help.
> For the record we are running with dual 64-bit chips with 8 GB of memory. I
> have noticed that the only 6.5 % of the memory is being used for this and
> the load is only at just over 1.
Sounds like your machine is I/O starved. What's your CPU utilization?
What's your shared_buffers set to? (not that it'll usually help a lot in
a backup usually, but if there's a lot of other access going on it
might)
How much memory is the KERNEL using as cache? PostgreSQL doesn't really
use a lot of memory by the way, relying on the kernel to cache for it.
You might wanna crank up effective_cache_size. That setting doesn't
allocate anything, it tells the planner about how much memory your OS is
using to cache the postgresql dataset. on a dedicated pgsql server with
8 gig ram, I'd expect it to be equal to about 7.5gig/8192.
Are you dumping to the same drive your database is on? Often dumping to
another drive helps a lot too.