Hi Johannes,
On Apr 20, 2010, at 9:19 AM, Stamminger, Johannes wrote:
> Hi,
>
> I was not aware of the reference of being a type of variable length.
Actually, only dataset region references are variable length. Object
references are fixed size.
Quincey
> So I assume it is the path string leading to the varying length?
> Naiv spoken I could imagine of having some hdf internal mapping of
> reference paths to an unique - fixed size - id to store a reference path
> only once. And in the references dataset the id would be used instead
> with getting the compression to work there then ... ?
>
> In principle this should be the same as you propose to implement on
> application layer, thanks for that. I will go this way then.
> Unfortunately this will double application calls (instead of internal
> ones) for each read/write of data ... :-(
>
> Best regards,
> Johannes Stamminger
>
>
> On Di, 2010-04-20 at 08:50 -0500, Elena Pourmal wrote:
>> Hi Johannes,
>>
>> As with other variable type data references cannot be compressed since
>> internally they are stored in the heaps while dataset itself stores pointers
>> to the data in a file. If size is a problem, you may come up with your own
>> set of indices stored in a dataset (for example, reference to a hyperslab
>> can be stored as 2 n-dim vectors of corner coordinates, or something like
>> this) and use compression.
>>
>> Elena
>>
>> On Apr 20, 2010, at 2:25 AM, Stamminger, Johannes wrote:
>>
>>> Hi,
>>>
>>> just a question related to this topic concerning the filesize: last week
>>> I played around with refernces a little bit. I created a dataset of
>>> 1-dim packet table of references. With 1,1 Mio references to hyperslab
>>> regions of other packet tables within the same file. And this increased
>>> the hdf file size dramatically. Seems to me as if compression does not
>>> work (well) for such refs ... or would you expect different result and I
>>> missed something there?
>>>
>>> Best regards,
>>> Johannes Stamminger
>
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