I would like to compress some Oracle tables to see how well they can
compress. Is there some sort of a guide or rules for how well tables
can compress based on their datatypes? I know that some of our DBA's
have managed to compress tables up to 70%.
What tables if any shouldn't be compressed? Are there datatypes that
compresses better or is it block related only?
I would like to understand and decide which tables should be compressed
without testing each table.
> I would like to compress some Oracle tables to see how...ZLIB Compression levels
I am using zlib 1.1.4 for Solaris and would like to know the
Is there a "C" api call that I can make on a compressed file that will
return me the compression level used to compress that file. If not,
can you provide me with a piece of code that can accomplish this task.
It would be very much appreciated.
Secondly, can you provide me with a list of compression levels. The
only ones I am aware of are below. Are these accurate?
email@example.com (Stu)...compression level in SSH2
How can one set compression level different than 6 in SSH2?
If it's impossible, why was it possible in SSH1?
There are big differences when I compared:
1) compression level 9 in SSH1,
2) compression level 6 in SSH2,
over a slow link, with huge amounts of text.
...Level 0 compression in ZipArchive
Is there a way to use php's ZipArchive and specify No Compression?
Something similar to "zip -0" on the command line. Thanks very much.
...JPEG compression and quality level
Is there a way or some (free) 3rd party algorithm to determine the JPEG
compression level? We need to make sure that some JPEGs have a certain
quality. Images under a some threshold value shall be rejected form
E.g. our JPEG quality scale would be from 0-100%, then all images below
70% can't be submitted. (100% is the lowest compression possible, large
Is there such an algorithm?
Karsten Wutzke <firstname.lastname@example.org> writes:
> Is there a way or some (free) 3rd party algorithm to determine the
> JPEG compression level...4-level image compression ?
I'm playing with a small system where the display is 320x240 pixels,
with 4 grey levels. So a picture takes about 19200 bytes.
Now I'm quite sure that these images can be reduced in size
but the algorithms I'm aware of deal with 2-level only (fax) or many-level
images (GIF/PNG etc.). Furthermore, my CPU power and RAM are quite reduced
so even a sub-optimal algorithm could do the trick, as long as it saves
some storage space. The final decoder will be hand-coded in asm
and developed in C.
currently, my idea is to use a paeth predictor followed
by a static huffman encoded en...Compression in PS level 2
I want to compress image data in PS using language level 2.
How to use runlength and other filters to get this done.....
"Needo" <email@example.com> wrote:
>I want to compress image data in PS using language level 2.
>How to use runlength and other filters to get this done.....
The PostScript Language Reference has the details, and either defines
the compressed data format, or gives a refererence to where it is
Some filters are very simple to compress for (RunLength), for some you
would use outside code (e.g. zlib for FlateDecode), and for others
i...OT unbelieveable PNG compression
Here is a picture that contains full RGB colours 256x256x256. Each pixel is
represented by different colour and the picture containr full 16.8M colours.
The picture has resolution 4096x4096 pixels and the colours in the picture
are placed in the way to propose maximal possible compression in PNG format.
The size of this compressed picture is just 58kB.
source : http://www.dsl.sk/article.php?article=2850&title=
Bohus Kr�l wrote:
> Here is a picture that contains full RGB colours 256x256x256. Each pixel
> is represented by di...compression level with tarfile (w:gz) ?
I was wondering if it possible to specify a compression level when I
tar/gzip a file in Python using the tarfile module. I would like to
specify the highest (9) compression level for gzip.
t = tarfile.open(tar_file_name+'.tar.gz', mode='w:gz:9')
When I create a simple tar and then gzip it 'manually' with compression
level 9, I get a smaller archive than when I have this code execute with
the w:gz option.
Is the only way to accomplish the higher rate to create a tar file
and then use a different module to gzip it (assuming I can specify