[Zope] Memory and Large Zope Page Templates

[Santi Camps]

En/na Chris Withers ha escrit:

> Santi Camps wrote:
>
>> Yes, I understant how ZODB cache works with threads.   The behaviour 
>> I didn't understood is why, once transaction is finished, the ZODB 
>> Cache decrese in number of objects but the RAM process not.
>
>
> This is the pythonic behaviour I was talking about.
> If you want it fixed, bug Guido ;-)
>
>> I'm already using brains.  I've tried your suggestion of 
>> subtransactions, but there is no change (I think it's normal, I'm not 
>> changing any persistent object).  I'm not sure how a _p_jar.sync() 
>> can improve something.
>
>
> ...you need to force the cache to garbage collect before there are too 
> many objects in memory. The catalog does this using subtransactions. 
> there's also a cache minimize call somewhere, but you're probably 
> better off asking on zodb-dev at zope.org about where that is...
>
Hi again,

I reply just to put the answer here, in order to be useful someone else.

Following Chris instructions, I've looked at ZCatalogs code and found 
the way to free memory:

1) Use subtransactions when changing data, adding a 
get_transaction().commit(1) every X steps

2) Explicitly call the garbage collector of the connection every X 
steps, forcing the conection to release objects from cache and be 
adjusted to cache parameters defined in zope.conf.   This can be done 
with a self._p_jar.cacheGC()   (where self is a persistent object, 
obviously)

In my case, a readonly report, the second method is enought to keep 
memory in place.

Thanks very much to everybody

Santi Camps