Re: [Zope-dev] Re: When should one call Connection.sync?
Dieter Maurer <[EMAIL PROTECTED]> writes:
> Syver Enstad wrote at 2004-4-21 18:03 +0200:
> >I have done some experiments with this scheme and I find that
> >everything gets unloaded when do a connection.close() or
> >connection.sync() so that performance takes quite a hit.
>
> Maybe, the connection cache is too small.
>
> Usually, an incremental cache garbage collection is performed
> in "connection.close()" and at transaction boundaries
> ("sync" causes an implicit "transaction.abort()" which means,
> it marks a transaction boundary). The cache garbage collection
> tries to flush as many objects from the cache as are necessary
> to reach the target cache size.
Yes that was the problem, I found out about this after some
experiments and by upping the cache_size to at least 20 000 I manage
to keep the instances in memory even when I do a sync or close.
Thank you anyway.
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Re: [Zope-dev] Re: When should one call Connection.sync?
Syver Enstad wrote at 2004-4-21 18:03 +0200:
>Syver Enstad <[EMAIL PROTECTED]> writes:
>
>> I am using ZODB 3.2 in a twisted based web application. I have read
>> that I need to call sync to keep the connection up to date. When
>> exactly should I call sync? Are there any drawbacks with calling it
>> immediately after getting a connection, like this:
>>
>> # for each http request.
>> connection = db.open() # (a DB instance)
>> connection.setLocalTransaction()
>> connection.sync()
>>
>> # start using the ZODB here.
>>
>> # if something needs to be committed
>> connection.getTransaction().commit()
>
>I have done some experiments with this scheme and I find that
>everything gets unloaded when do a connection.close() or
>connection.sync() so that performance takes quite a hit.
Maybe, the connection cache is too small.
Usually, an incremental cache garbage collection is performed
in "connection.close()" and at transaction boundaries
("sync" causes an implicit "transaction.abort()" which means,
it marks a transaction boundary). The cache garbage collection
tries to flush as many objects from the cache as are necessary
to reach the target cache size.
--
Dieter
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[Zope-dev] Re: When should one call Connection.sync?
Syver Enstad <[EMAIL PROTECTED]> writes: > I am using ZODB 3.2 in a twisted based web application. I have read > that I need to call sync to keep the connection up to date. When > exactly should I call sync? Are there any drawbacks with calling it > immediately after getting a connection, like this: > > # for each http request. > connection = db.open() # (a DB instance) > connection.setLocalTransaction() > connection.sync() > > # start using the ZODB here. > > # if something needs to be committed > connection.getTransaction().commit() I have done some experiments with this scheme and I find that everything gets unloaded when do a connection.close() or connection.sync() so that performance takes quite a hit. ___ Zope-Dev maillist - [EMAIL PROTECTED] http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
