[Pgpool-general] max_pool and num_init_chi

[Nico -telmich- Schottelius]

Hello...hopefully a not so confused mail:

I am searching for the right values for:

- 2 backends, load balancing, replicating each accepts 200 Connections
- 4 Databases
- 2 web servers (=clients)

Most hits will be made on one database.

On http://pgpool.projects.postgresql.org/ I read:

"num_init_children ... f you want to ensure that queries can be
cancelled, set this value to twice the expected connections. "

So I would set it to 800, as each backend*possible_cons = 2*200.
As reading the mail Message-Id:
<20080409.193049.1703984609.y-asaba at sraoss.co.jp>, I would favor

max_pool = 4

But this would make 3200 possible connections to the backends, which is
not what I intend.

So which variant would you recommened? Currently I think that

# maximum of 400 concurrent connections
num_init_children = 400 
max_pool = 1

would fit best.

I am anyway wondering, in which case the pool parameters makes sense, as
you write that:

  client-1  <--> pgpool-1
  client-2  <--> pgpool-2
  ...
  client-32 <--> pgpool-32

Do you mean client-1 = one connection or one host? As we have only two
hosts, we could set num_init_children = 4 and max_pool = 100.
If it is one connection (what I guess) num_init_children = 400 and
max_pool = 1 makes more sense I guess...

Nico

-- 
Think about Free and Open Source Software (FOSS).
http://nico.schottelius.org/documentations/foss/the-term-foss/

PGP: BFE4 C736 ABE5 406F 8F42  F7CF B8BE F92A 9885 188C
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