[Zope] Database adapter connections

[Michal Bukovjan]

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Dieter Maurer wrote:

>Michal Bukovjan writes:
> > I have a database adapter, Level3 (inheriting from Shared.DC.ZRDB.TM).
> > All documentation I have found claims that such an adapter should be 
> > able to open multiple connections to the database, I see always one though.
>You do not tell us, what database you are using.
>
>When, e.g., your Python DB API module is not multi-thread aware,
>then the Global Interpreter Lock is not released and only
>a single thread can run at a time.
>
>This is, e.g., a problem for ZODBCDA.
>
>
>Dieter
>
I was talking about my own hacked version of Interbase DA, that is 
gvibDA / gvib Python API module (also changed/hacked by me).

I am experimenting with this, resolving some threading issues, and try 
to get more performance.
I found that, for instance, Zope never looks at threadsafety variable 
defined by the API variable.

The API actually releases the Global Interpreter lock during longer 
lasting operations like fetch or execute  (if we are talking about 
Py_THREADS_ALLOW_BEGIN / END combos), but at any case, there is always 
only one physical connection (I can tell it by number of active DB 
server connections), which is being used by multiple Zope threads.

A second connection is never started, no matter how I changed the gvibDA 
/ gvib so far.

Michal

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