[Pgpool-general] [pgpool-general] num_init_children * max_pool

[Willy-Bas Loos]

Hi,

I'm new to pgpool and to the mailing list. I didn't find answers to my
questions below with google, nor in the manual, so i hope i am not asking
the same old basic questions, sorry if so.
I intend to use pgpool for connection pooling in 2 instances.
1. where i start a dblink request per record. It's always the same
host+port+user+databae.
2. instead of fast-cgi for mapserver. If i'm going to use pgpool foor
connection pooling, i don't need to get into fast-cgi.

I just read the
manual<http://pgpool.projects.postgresql.org/pgpool-II/doc/pgpool-en.html>,
and i am confused by the following statements:

In the section Configuring pgpool.conf, Connection Pool Mode:
"Please be aware that the number of connections from pgpool-II processes to
the backend will be num_init_children * max_pool."

In the section Configuring pgpool.conf, raw Mode:
"num_init_children: The number of preforked pgpool-II server processes.
Default is 32. Please note that cancelling a query creates another
connection to the backend; thus, a query cannot be cancelled if the
connections are full."

I am guessing that pg_pool already starts 32 processes that give access to a
connection that is requested.
This would cost resources for the first connection, but be faster when the
next request comes in.

Is the "backend" mentioned here the database backend or some pgpool backend?
If it is the database, then i don't see how this is a connection pooling
solution. In that case there would still be as many connections to the
database as without pgpool, with 2 differences: the server starts out with
128 idle connections to the db, and connection requests exceeding the max
number will be put on hold.

I would greatly appreciate any insight in these matters.

cheers,

WBL



-- 
"Patriotism is the conviction that your country is superior to all others
because you were born in it." -- George Bernard Shaw
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