Correction:
I didn't notice the 8k per unit settings at first with postgres 8.1.
Should read:
effective_cache_size = 786432 # 6Gb
On 06/04/2010 10:58 AM, Stephen Thompson wrote:
>
>
> Hello everyone,
>
> We recently attempted a mysql to postgresql migration for our bacula
> 5.0.2 server. The data migration itself was successful, however we are
> disappointly either getting the same or significantly worse performance
> out of the postgres db.
>
> I was hoping that someone might have some insight into this.
>
> Here is some background:
>
> software:
> centos 5.5 (64bit)
> bacula 5.0.2 (64bit)
> postgresql 8.1.21 (64bit)
> (previously... mysql-5.0.77 (64bit) MyISAM)
>
> database:
> select count(*) from File --> 1,439,626,558
> du -sk /var/lib/pgsql/data --> 346,236,136 /var/lib/pgsql/data
>
> hardware:
> 1Tb EXT3 external fibre-RAID storage
> 8Gb RAM
> 2Gb SWAP
> 2 dual-core [AMD Opteron(tm) Processor 2220] CPUs
>
>
> Some of the postgres tuning that I've attempted thus far (comments are
> either default or alternatively settings I've tried without effect):
>
> #shared_buffers = 1000 # min 16 or max_connections*2, 8KB each
> shared_buffers = 262144 # 2Gb
> #work_mem = 1024 # min 64, size in KB
> work_mem = 524288 # 512Mb
> #maintenance_work_mem = 16384 # min 1024, size in KB
> maintenance_work_mem = 2097152 # 2Gb
> #checkpoint_segments = 3 # in logfile segments, min 1, 16MB each
> checkpoint_segments = 16
> #checkpoint_warning = 30 # in seconds, 0 is off
> checkpoint_warning = 16
> #effective_cache_size = 1000 # typically 8KB each
> #effective_cache_size = 262144 # 256Mb
> effective_cache_size = 6291456 # 6Gb
> #random_page_cost = 4 # units are one sequential page fetch cost
> random_page_cost = 2
>
> Now, as to what I'm 'seeing'. Building restore trees are on par with my
> previous mysql db, but what I'm seeing as significantly worse are:
>
> mysql postgresql
> Within Bat:
> 1) Version Browser (large sample job) 3min 9min
> 2) Restore Tree (average sample job) 40sec 25sec
> 3) Restore Tree (large sample job) 10min 8.5min
> 2) Jobs Run (1000 Records) 10sec 2min
>
> Within psql/mysql:
> 1) select count(*) from File; 1sec 30min
>
> Catalog dump:
> 1) mysqldump/pgdump 2hrs 3hrs
>
>
> I get a win on building Restore trees, but everywhere else, it's
> painfully slow. It makes the bat utility virtually unusable as an
> interface. Why the win (albeit moderate) in some cases but terrible
> responses in others?
>
> I admit that I am not familiar with postgres at all, but I tried to walk
> through some of the postgres tuning documents, including the notes in
> the bacula manual to arrive at the above settings. Also note that I've
> tried several variants on the configuration above (including the
> postgres defaults), don't have a detailed play by play of the results,
> but the time results above seemed typical regardless of what settings I
> tweaked.
>
> Any help would be greatly appreciated!
> Stephen
--
Stephen Thompson Berkeley Seismological Laboratory
stephen AT seismo.berkeley DOT edu 215 McCone Hall # 4760
404.538.7077 (phone) University of California, Berkeley
510.643.5811 (fax) Berkeley, CA 94720-4760
------------------------------------------------------------------------------
ThinkGeek and WIRED's GeekDad team up for the Ultimate
GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the
lucky parental unit. See the prize list and enter to win:
http://p.sf.net/sfu/thinkgeek-promo
_______________________________________________
Bacula-users mailing list
Bacula-users AT lists.sourceforge DOT net
https://lists.sourceforge.net/lists/listinfo/bacula-users
|
