[pgpool-general: 6426] Re: Request for support regarding pg pool hardware sizing

[Tatsuo Ishii]

> Dears
> 
> I need to know if there are specific guidelines for hardware sizing for pg
> pool server since I can't find enough information online.
> 
> Can anyone guide me on this? or tell me what numbers are needed from my
> side to be able to estimate the hardware sizing needed?
> 
> I'm interested more in terms of CPU and RAM in the current status.

Here are very rough guide lines.

- Basic RAM requirement: 5MB * num_init_children. For example if you
  have num_init_children = 32 (the default), you need 160MB.

- Shared memory: num_init_children * max_pool * 17408. For example if
  you have num_init_children = 32 (the default) and max_pool = 4 (the
  default), you need 32 * 4 * 17408 = 2228224 bytes = 2.1 MB.

- If you plan to use in memory query cache with shared memory, you
  need more RAM for it. See memqcache_max_num_cache section in the
  Pgpool-II doc for required RAM size.

- If you plan to use extended query protocol (i.e. prepared queries in
  Java and other languages), existing releases may consume much more
  RAM. It will be fixed in the next minor releases, planed to be
  released on February 21th.

- If you plan to assign large number to num_init_children, you need
  more CPU. It's hard to tell exactly how many cores you need, because
  that's depending on what type of SQL queries you are going to use.
  If a query does not take long time in PostgreSQL, it is likely that
  more CPU is consumed by Pgpool-II. On the other hand, if a query
  takes long time, Pgpool-II needs less CPU.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp