[pgpool-general: 599] Re: About configuration parameters

[Tatsuo Ishii]

> Hello everyone in the list. In other mails I asked about this topic, but I have some doubt with this configuration parameters. As I know, connection pooling software like pgpool-II, has a number of connections opened and reuses them whenever a new connection with the same properties comes in. 
> 
> About these configuration parameters: 
> 
> max_connections: Is the maximum concurrent connections between clients and postgresql server. (postgresql property) 
> 
> num_init_children: Like max_connections, it is the maximum concurrent connections between clients and pgpool-II. (pgpool property) 
> 
> max_pool: The maximum number of cached connections in pgpool-II children processes. pgpool-II reuses the cached connection if an incoming connection is connecting to the same database with the same username. If not, pgpool-II creates a new connection to the backend. If the number of cached connections exceeds max_pool, the oldest connection will be discarded, and uses that slot for the new connection. (According pgpool-II documentation) 
> 
> 
> 1. Why max_connexion must satisfy this formula max_connexion >= (Nun_init_children * max_pool) and not this max_connexion >= nun_init_children? 
> 
> 2. A child process only opens one connection in the database server and it can be use concurrently (max_pool), or for each child process, it open a total of max_pool connections in the database server? 
> 
> 3. When is possible that the number of cached connections exceeds max_pool? 

Have you read this section in the pgpool doc? If yes and still have
questions please clarify. I would love to hear from you to enhance our
document.

<dt><a name="MAX_POOL"></a>max_pool</dt>
    <dd>
    <p>The maximum number of cached connections in pgpool-II children processes.
    pgpool-II reuses the cached connection if an incoming connection is
    connecting to the same database with the same username.
    If not, pgpool-II creates a new connection to the backend.
    If the number of cached connections exceeds max_pool,
    the oldest connection will be discarded, and uses that slot for the new connection.

> The answers about these questions are welcome. 
> Thank you very much for your time and sorry for such insistence. 
> Regards 
> 
> 
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