topic Re: CL_ABAP_GZIP - Compression Level in Application Development and Automation Discussions

CL_ABAP_GZIP - Compression Level

SebastianK — Fri, 17 May 2013 09:06:30 GMT

Hi Experts,

does anyone of you has experience with the optional compression level parameter? I have compressed several xstrings with different length but all compression levels from 1-9 result in the same file size for each xstring. It is like the parameter is not used by the routine. Maybe there are changes in newer Netweaver releases but as I can tell from NW 6.20 (4.7) and 7.00 this parameter does not change the compression level resp. the file size.

Regards Sebastian

Re: CL_ABAP_GZIP - Compression Level

arindam_m — Fri, 17 May 2013 10:21:07 GMT

Hi,

I think the compression levels wont matter much if then data is small and also if data cannot be compressed any further.

Cheers,

Arindam

Re: CL_ABAP_GZIP - Compression Level

SuhaSaha — Fri, 17 May 2013 10:37:53 GMT

Hello Sebastian,

It is like the parameter is not used by the routine

This method uses the Kernel magic wand (read: method) ab_compressBinary. So there is no way us ABAPers can influence it in any way rather than thinking & speculating

BR,

Suhas

Re: CL_ABAP_GZIP - Compression Level

custodio_deoliveira — Fri, 17 May 2013 11:40:20 GMT

Hi Sebastian,

According to method documentation (believe or not, Suhas, there's documentation!!!), compression level has more to do with speed than size:

COMPRESS_LEVEL
Optional specification of the compression level. This must be between 0 and 9, where 1 is the fastest and 9 the highest compression. 0 means that no compression takes place. The deafult value is 6.

To read full method doco, place cursor in a method and click on documentation icon:

Regards,

Custodio

@zcust01

Re: CL_ABAP_GZIP - Compression Level

SuhaSaha — Fri, 17 May 2013 11:49:14 GMT

According to method documentation (believe or not, Suhas, there's documentation!!!), compression level has more to do with speed than size:

Hey Custodio,

SAP documentation is the first thing i check before using any method/function May be in this case we interpreted the documentation in different ways -

This must be between 0 and 9, where 1 is the fastest and 9 the highest compression.

I think that 1 is the fastest (& the lowest) compression with 9 being the highest compression (& the slowest) . Try to add a file to any ZIP archive (using WinZip, WinRAR et al.) you'll see the compression level from the Fastest ---> Highest.

Happy to hear your comments.

BR,

Suhas

Re: CL_ABAP_GZIP - Compression Level

custodio_deoliveira — Fri, 17 May 2013 11:56:22 GMT

Hi Suhas,

Not saying you don't check it, just sometimes we (at least I) forget to check individual methods doco and read only the class doco.

Anyway, I think you are right, I probably misinterpreted the doco.

Cheers,

Custodio

Re: CL_ABAP_GZIP - Compression Level

SebastianK — Fri, 17 May 2013 12:09:51 GMT

That was exactly my expectation when I was reading the documentation in the first place. In fact the documentation tells something about speed and compression BUT if I create a simple report and run this method with all numbers from 0 to 9 (even 0 compresses!) then the runtime and compression rate is the same for all 10 variations. Even if I vary the xstring input between large and mid size binarys there is no difference. I think that compression level is just a placeholder and SAP did not implement this feature in its kernel yet 😕