Optimisation help

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From: dforums <dforums@vieonet.com>
To: pgsql-performance@postgresql.org
Subject: Optimisation help
Date: Tue, 04 Mar 2008 22:21:22 +0000
Message-ID: <47CDCB62.9070302@vieonet.com> (raw)

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Hello<br>
<br>
<br>
We hace a Quad Xeon server, with 8GO of ram, sata II 750Go<br>
<br>
An postgresql database, of 10 Go<br>
<br>
I have several treatment every 2 minutes who select, insert, update
thousand of data in a table. It take a lot of time (0.3300 ms per line)
just to check if a string of 15 char is present, and decide to update
it under few constraint<br>
<br>
I suppose the main problem is from database server settings.<br>
<br>
This is my settings : <br>
<br>
<br>
max_connections = 256<br>
shared_buffers = 1500&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # min 16 or max_connections*2,
8KB each<br>
temp_buffers = 500&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # min 100, 8KB each<br>
max_prepared_transactions = 100 <br>
<br>
work_mem = 22000&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # min 64, size in KB<br>
maintenance_work_mem = 500000&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # min 1024, size in KB<br>
max_stack_depth = 8192 <br>
<br>
<br>
max_fsm_pages = 100000&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # min max_fsm_relations*16, 6
bytes each<br>
max_fsm_relations = 5000&nbsp; <br>
<br>
<br>
vacuum_cost_delay = 50&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # 0-1000 milliseconds<br>
vacuum_cost_page_hit = 1000&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # 0-10000 credits<br>
vacuum_cost_page_miss = 1000&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # 0-10000 credits<br>
vacuum_cost_page_dirty = 120&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # 0-10000 credits<br>
vacuum_cost_limit = 2000&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # 0-10000 credits<br>
<br>
# - Background writer -<br>
<br>
bgwriter_delay = 50&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # 10-10000 milliseconds between
rounds<br>
bgwriter_lru_percent = 1.0&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # 0-100% of LRU buffers
scanned/round<br>
bgwriter_lru_maxpages = 25&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # 0-1000 buffers max
written/round<br>
bgwriter_all_percent = 0.333&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # 0-100% of all buffers
scanned/round<br>
bgwriter_all_maxpages = 50&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # 0-1000 buffers max
written/round<br>
<br>
wal_buffers = 16&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # min 4, 8KB each<br>
commit_delay = 500&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # range 0-100000, in
microseconds<br>
commit_siblings = 50&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # range 1-1000<br>
<br>
# - Checkpoints -<br>
<br>
checkpoint_segments = 50&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # in logfile segments, min 1,
16MB each<br>
checkpoint_timeout = 1800&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # range 30-3600, in seconds<br>
checkpoint_warning = 180&nbsp;&nbsp;&nbsp; <br>
<br>
effective_cache_size = 2048&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; # typically 8KB each<br>
random_page_cost = 3&nbsp;&nbsp; <br>
<br>
<br>
Shared memory set to :<br>
echo /proc/sys/kernel/shmmax = 256000000<br>
<br>
Could you help&nbsp; please...<br>
<br>
tx<br>
<br>
<br>
David<br>
<br>
<br>
<br>
<br>
<br>
<br>
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