Thanks John - just to clarify, at the moment files are only removed if
the number of elements is exceeded, and their age in the cache is
disregarded?
Out of interest, what was the main motivation for creating the cache
system, i.e. what is the expensive operation that you are optimizing?
Cheers, Jon
On Mon, Sep 28, 2009 at 5:57 PM, John Caron <caron@xxxxxxxxxxxxxxxx> wrote:
> Jon Blower wrote:
>>
>> Dear all (esp. John),
>>
>> I think I have been misunderstanding the intended behaviour of the
>> cache of NetCDF files (the one that's initialized with
>> NetcdfDataset.initNetcdfFileCache()).
>>
>> What is the behaviour of the "periodic cleanup"? Does it remove
>> elements from memory only when the number of elements in memory
>> exceeds a certain number? Or does it also remove elements based on
>> their age?
>
> every n minutes it removes files using LRU.
>>
>> The behaviour I would like is the latter - i.e. I would like to be
>> able to guarantee that the elements in the cache are no older than,
>> say, five minutes. But this isn't the behaviour I'm seeing: elements
>> seem to persist essentially for ever. So perhaps the former behaviour
>> is the correct one? In which case, how would you recommend I
>> implement the latter behaviour?
>
> ill probably move to ehcache (version 4.2?), which i think allows this.
> ill have to look at the code for a workaround...
>
>
>>
>> (Rich and Clare - I think this might be causing the caching problems
>> you are seeing with ncWMS.)
>>
>> Thanks,
>> Jon
>>
>
>
--
Dr Jon Blower
Technical Director, Reading e-Science Centre
Environmental Systems Science Centre
University of Reading
Harry Pitt Building, 3 Earley Gate
Reading RG6 6AL. UK
Tel: +44 (0)118 378 5213
Fax: +44 (0)118 378 6413
j.d.blower@xxxxxxxxxxxxx
http://www.nerc-essc.ac.uk/People/Staff/Blower_J.htm
