[Zope] Re: kInterbaseDA multiple connection

Tres Seaver tseaver at zope.com
Sun Feb 20 09:07:14 EST 2005


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Konstantin E. Steuck wrote:
| Thanks for you reply, Tres
|
| Tres Seaver wrote:
|
|  > Each application server thread in your application holds a separate
|  > instance of the adapter, which means that unless the adapter is coded
|  > (which I doubt) to multiplex requests from separate instances across a
|  > single, global connection, you could see as many connections as you
|  > have appserver threads.
|
| Does it mean that number of active connections can grow even more due to
| thread count growth? Will it decrease when the thread stops?

By default, Zope is configured to run with four appserver threads (see
the 'zserver-threads' option in zope.conf).  I misspoke slightly in my
first post:  the DA connection is actually held inside a database
connection, of which there are seven by default (the 'connection-pool'
zope.conf parameter controls this).

Normally, an appserver thread acquires a connection at the start of the
request, and the returns it to the pool of available connections.  So,
the absolute maximum number of open DA connections is the number of ZODB
database connections in the pool (7), while the "likely" high number is
lower, depending on your usage patterns (4 if all 4 appserver threads
stay busy, and use the DA).

Tres.
- --
===============================================================
Tres Seaver                                tseaver at zope.com
Zope Corporation      "Zope Dealers"       http://www.zope.com
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