tuning apache2 mod_wdgi + TG 2.1.3 + Postgres

[NiL]

Hi list,

in apache conf I have

WSGIDaemonProcess myapp threads=10 processes=20 display-name=%{GROUP}

in myapp/config/app_cfg.py

I don't have anything specific so

class QueuePool(Pool):
    """A Pool that imposes a limit on the number of open connections."""

    def __init__(self, creator, pool_size=5, max_overflow=10, timeout=30,
                 **kw):
                
applies. I read in sqla's strategies that this is the default

when I stress the app with jmeter (250 connections on 30 seconds), I quickly have

OperationalError: (OperationalError) FATAL: too many clients already connected

in apache/error.log and that comes from Postgres.
(in postgres.conf max_connections is 200)

So what I'd like to understand is how to evaluate the max number of connection that my app will open to the dbms

tx

NIL

[Alessandro Molina]

Each process of your application will open up to 15 connections (5 +
10 for momentary bursts) to the DB Server and will close them when
"pool_recycle" timeout triggers.

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[Christoph Zwerschke]

Am 02.12.2011 14:25, schrieb NiL:
> So what I'd like to understand is how to evaluate the max number of
> connection that my app will open to the dbms

Each process will have its own pool of connections, each pool has a
maximum of pool_size + max_overflow connections.

So in your case, you have up to 20 * (5 + 10) = 300 connections which is
greater than max_connections allows.

-- Christoph

[NiL]

thank you very much !
I'll try to tune now (of course it's not that easy, I have several other process that binds to PG)