Re: [ROOT] R__zip: output buffer too small for in-memory compression

From: Rene Brun (Rene.Brun@cern.ch)
Date: Sun Sep 14 2003 - 22:54:34 MEST


Hi Susan,

This warning is printed when the compression algorithm fails to compress
the current buffer. This may happen in some peculiar combinations of 
buffer size and type of data, in particular with random data.
There is no way to remove this message in your version.
As you have found the result is correct. An uncompressed buffer is used
in this case.

Rene Brun

On 
Sun, 14 Sep 2003, Susan Kasahara wrote:

> Hi roottalk,
> I am seeing this error:
> 
>   R__zip: output buffer too small for in-memory compression
> 
> when saving a tree that contains many finely split branches (splitlevel=99)
> to file.  I have traced the occurrence of the error back to the compression of the TBasket buffer
> associated with one particular branch of this tree:
> 
>   fHeader.fVldContext.fTimeStamp.fNanoSec
> 
> where fNanoSec is of type Int_t.
> The R__zip message is generated with every AutoSave of the tree
> containing this branch, and is always associated with the compression of this particular
> branch data buffer.  There are 470 branches on this tree and none
> but the fNanoSec branch produces this error.
>     I'm wondering if I should be concerned.  I see that when the
> R__zip error occurs, the compression is skipped for this basket buffer,
> but the buffer is written out to file successfully uncompressed.  I am also
> able to read the fNanoSec branch data successfully.
>   I am using ROOT v3.05.07 built from source code downloaded from
> the root web site on 9/10/03, compiled with gcc 3.2 on rh linux release 9.
> Thanks in advance for any help you can give me,
> -Sue Kasahara
> 
> p.s. Some debug printout in case it helps:
> R__zip: output buffer too small for in-memory compression
> R__zip: output buffer too small for in-memory compression
> R__zip: output buffer too small for in-memory compression
> R__zip: output buffer too small for in-memory compression
> out_offset=14, len=2128, out_size=2128
> out_offset=14, len=2132, out_size=2132
> out_offset=14, len=2076, out_size=2076
> out_offset=14, len=2188, out_size=2188
> 
> 
> 
> 



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