Feature #43324: Make zlib windowBits configurable for compression - RADOS - Ceph

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Feature #43324

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Make zlib windowBits configurable for compression

Added by Xiyuan Wang over 4 years ago. Updated almost 4 years ago.

Status:

Resolved

Priority:

Normal

Assignee:

Category:

Administration/Usability

Target version:

Ceph - v15.0.0

% Done:

Source:

Community (dev)

Tags:

Backport:

Reviewed:

Affected Versions:

Component(RADOS):

Pull request ID:

34852

Description

Now the zlib windowBits is hardcoding as -15¹. But it should be set to different value for different case.

According to zlib guide², windowBits can be set to [-15, -8) for raw deflate, (8, 15] for compression with header and trailer and [16,) for optional gzip encoding.

And now we meet an requirement to use 15 for zlib windowBits.

So for Ceph, is it possible to make `ZLIB_DEFAULT_WIN_SIZE` configurable to support different compression case?

[1]: https://github.com/ceph/ceph/blob/master/src/compressor/zlib/ZlibCompressor.cc#L43
[2]: https://github.com/madler/zlib/blob/cacf7f1d4e3d44d871b605da3b647f07d718623f/zlib.h#L552-L576

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Updated by Xiyuan Wang over 4 years ago

Xiyuan Wang wrote:

Now the zlib windowBits is hardcoding as -15¹. But it should be set to different value for different case.

According to zlib guide², windowBits can be set to [-15, -8) for raw deflate, (8, 15] for compression with header and trailer and [16,) for optional gzip encoding.

And now we meet an requirement to use 15 for zlib windowBits.

So for Ceph community, is it possible to make `ZLIB_DEFAULT_WIN_SIZE` configurable to support different compression case? If yes, I can contribute the code to upstream.

[1]: https://github.com/ceph/ceph/blob/master/src/compressor/zlib/ZlibCompressor.cc#L43
[2]: https://github.com/madler/zlib/blob/cacf7f1d4e3d44d871b605da3b647f07d718623f/zlib.h#L552-L576