Re: [REVIEW] Re: Compression of full-page-writes

On Thu, Dec 25, 2014 at 10:10 PM, Michael Paquier
<michael(dot)paquier(at)gmail(dot)com> wrote:
> On Wed, Dec 24, 2014 at 9:03 PM, Michael Paquier
> <michael(dot)paquier(at)gmail(dot)com> wrote:
>> Returning only a boolean is fine for me (that's what my first patch
>> did), especially if we add at some point hooks for compression and
>> decompression calls.
> Here is a patch rebased on current HEAD (60838df) for the core feature
> with the APIs of pglz using booleans as return values.
After the revert of 1st patch moving pglz to src/common, I have
reworked both patches, resulting in the attached.

For pglz, the dependency to varlena has been removed to make the code
able to run independently on both frontend and backend sides. In order
to do that the APIs of pglz_compress and pglz_decompress have been
changed a bit:
- pglz_compress returns the number of bytes compressed.
- pglz_decompress takes as additional argument the compressed length
of the buffer, and returns the number of bytes decompressed instead of
a simple boolean for consistency with the compression API.
PGLZ_Header is not modified to keep the on-disk format intact.

The WAL compression patch is realigned based on those changes.
Regards,
--
Michael