On Mon, Sep 15, 2008 at 11:55 AM, Martin Langhoff
<martin.langhoff@gmail.com> wrote:
> ... so RAM allocation for Pg will prob range between 32MB at the
> lower-end and 128MB/196MB at the 1GB "recommended" RAM.
Assuming a 128MB target, I've been poking and probing with the
postgresql.conf and the new settings...
- 1/4 of it to shared buffers
- 45 max connections - matched to a max of 40 apache/php processes
- 2MB work_mem (some complex queries in Moodle require sorts)
means 32MB shmem and an unlikely maximum of 90MB taken for work_mem.
There is 6MB left over in my "budget" which I expect will be consumed
by per-connection overheads. When I start up Pg on this machine,
ps_mem.py (a nice smap parse-and-summarise tool) tells me a completely
idle postmaster:
Private + Shared = RAM used Program
(...)
2.9 MiB + 1.0 MiB = 3.9 MiB postmaster (6)
These are the changes I'm making to the default postgresql.conf:
+max_connections = 45
+## work_mem can also cost up to max_connections * work_mem
+
+shared_buffers = 32MB
+temp_buffers = 8MB
+max_prepared_transactions = 5
+work_mem = 2MB
+maintenance_work_mem = 16MB
+max_stack_depth = 2MB
+wal_buffers = 1MB
+wal_writer_delay = 1000ms
cheers,
m
--
martin.langhoff@gmail.com
martin@laptop.org -- School Server Architect
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