Re: PostgreSQL + FreeBSD memory configuration, and an issue

On Fri, Apr 8, 2011 at 4:00 AM, Gipsz Jakab <clausewitz45(at)gmail(dot)com> wrote:

> My question is the following: if this is a dedicated database server, with
> maximum 30 users (but they are using ODBC with Microsoft Acces, and each of
> them generating 4-6 connection at the same time), and other 200 people will
> use this server through drupal, php, apache not in daily basis, but weekly,
> what is the ideal memory configuration?
>

if it is a dedicated DB server, then give shared memory about 1/4 of the
RAM, and perhaps a slightly larger maintenance work mem. depending on your
workload you may want to increase the checkpoint segments (if write-mostly,
then add more segments).

Here is what I use on my FreeBSD 8, Pg 9 big-memory servers. these have
24GB or more of RAM and are attached to SSD external storage for the
database:

max_connections = 200
shared_buffers = 5120MB
work_mem = 512MB
maintenance_work_mem = 1024MB
max_stack_depth = 8MB
vacuum_cost_delay = 15checkpoint_segments = 64
checkpoint_timeout = 15min
checkpoint_completion_target = 0.8
random_page_cost = 1.0 # RAM disk. set equal seq_page_cost
effective_cache_size = 6400MB # shared_buffers + `sysctl -n
vfs.hibufspace` / 8192 (BLKSZ)

for individual complicated queries, you can increase the sort mem and work
mem on a per-connection basis as needed.

>
> After the settings in the postgresql.conf our system is much faster, and no
> more error messages in the postgres.log, but If I try to drop a table, or
> add a new one, our system is stopping, until I kill the process, which is
> dropping or adding a table.
>

Is something else using the table you want to drop and blocking the drop
statement from taking the locks it needs? It should be fairly instant.