On 15/08/2007, at 5:36 PM, [EMAIL PROTECTED] wrote:

> On Wed, Aug 15, 2007 at 08:40:28AM +1000, David Worrall wrote:
>
>> My RAM is 256Mb on OSX 10.4.10 (the latest).
>
> Mmmm, not so good ;)  I think what is happening is that your
> computer is getting out of memory resources.  A Table node should use
> around 1 MB of memory, and the number of slots in the PyTables' node
> cache (NODE_MAX_SLOTS) is 256 by default.  This means that with 256 MB
> you are completely filling it (i.e. the system will start using swap),
> and that could be the source of the problem you are experiencing.
> My advice is that you should try with a machine with at least 512 MB,
> or better yet, try lowering NODE_MAX_SLOTS to, say, 64.
>
Arrrrrh! I made a mistake - it is actually 512Mb - sorry.
....

>> Also, is there any reason why I can't/shouldn't use 2 or more .h5
>> files in parallel (split the 3500+ top-level groups into two DBs)?
>
> As Ivan has already said, this perfectly fine with PyTables.  However,
> this will only worse the memory problem, as each opened file will have
> its own node cache, raising still more your memory needs.  So, if
> you are dealing with a very large amount of nodes and have not much
> memory available, it is better to stay with only one opened file at a
> time.

I understand that, however it means I might be able to find a way to  
meaningfully segment the DB so each segment-DB  is smaller.
As I think I mentioned earlier, I did success in generating a  
complete DB by loading 1/2 of it, closing the file, quitting python   
and then starting again with the same file, adding the 2nd 1/2.

All that aside,
1. it is a worry that there is no exception generated, by python, at  
least,  don't you agree?
2. Is there a way of purging memory after a flush or are we up  
against python's memory management?

> Cheers,
>
> Francesc
>

thanks a lot for your help,
David
_________________________________________________
experimental polymedia: www.avatar.com.au
Sonic Communications Research Group,
University of Canberra:  creative.canberra.edu.au/scrg





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