Hello,
After controling the settings I so, that shared_buffers is configurated
at 1024 (the default), however, in my postgresql.conf I set it to
250000, is it due to shared memory settings, should I increase shmmax?
regards
david
Greg Smith a écrit :
On Tue, 4 Mar 2008, dforums wrote:
max_connections = 256
shared_buffers = 1500 # min 16 or max_connections*2,
8KB each
work_mem = 22000 # min 64, size in KB
effective_cache_size = 2048 # typically 8KB each
Well, you're giving the main database server a whopping 1500*8K=12MB of
space to work with. Meanwhile you're giving each of the 256 clients up
to 22MB of work_mem, which means they can use 5.6GB total. This is
quite backwards.
Increase shared_buffers to something like 250000 (2GB), decrease
work_mem to at most 10000 and probably lower, and raise
effective_cache_size to something like 5GB=625000. Whatever data you've
collected about performance with your current settings is pretty much
meaningless with only giving 12MB of memory to shared_buffers and having
a tiny setting for effective_cache_size.
Oh, and make sure you ANALYZE your tables regularly.
random_page_cost = 3
And you shouldn't be playing with that until you've got the memory usage
to something sane.
Also, you didn't mention what version of PostgreSQL you're using.
You'll need 8.1 or later to have any hope of using 8GB of RAM
effectively on a 4-core system.
But My most fear is that for now the database is only of 10 Go. But I
will have to increase it 10 times during the next six month I'm afraid
that these problems will increase.
It's very unlikely you will be able to get good performance on a 100GB
database with a single SATA drive. You should be able to get great
performance with the current size though.
In regards of update, I have around 10000 updates while a laps of 10
minutes. Is there a settings to optimise updates ?
10000 updates / 600 seconds = 17 updates/second. That's trivial; even a
single boring drive can get 100/second. As someone already suggested
your real problem here is that you'll be hard pressed to handle the
amount of seeking that goes into a larger database with only a single
drive.
--
* Greg Smith gsmith@xxxxxxxxxxxxx http://www.gregsmith.com Baltimore, MD
--
Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx)
To make changes to your Subscription:
http://mail.postgresql.org/mj/mj_wwwusr?domain=postgresql.org&extra=pgsql-performance
--
Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx)
To make changes to your Subscription:
http://mail.postgresql.org/mj/mj_wwwusr?domain=postgresql.org&extra=pgsql-performance
