On Mon, Jan 5, 2015 at 10:29 PM, Fujii Masao <masao.fu...@gmail.com> wrote: > On Sun, Dec 28, 2014 at 10:57 PM, Michael Paquier wrote: > The patch 1 cannot be applied to the master successfully because of > recent change. Yes, that's caused by ccb161b. Attached are rebased versions.
>> - The real stuff comes with patch 2, that implements the removal of >> PGLZ_Header, changing the APIs of compression and decompression to pglz to >> not have anymore toast metadata, this metadata being now localized in >> tuptoaster.c. Note that this patch protects the on-disk format (tested with >> pg_upgrade from 9.4 to a patched HEAD server). Here is how the APIs of >> compression and decompression look like with this patch, simply performing >> operations from a source to a destination: >> extern int32 pglz_compress(const char *source, int32 slen, char *dest, >> const PGLZ_Strategy *strategy); >> extern int32 pglz_decompress(const char *source, char *dest, >> int32 compressed_size, int32 raw_size); >> The return value of those functions is the number of bytes written in the >> destination buffer, and 0 if operation failed. > > So it's guaranteed that 0 is never returned in success case? I'm not sure > if that case can really happen, though. This is an inspiration from lz4 APIs. Wouldn't it be buggy for a compression algorithm to return a size of 0 bytes as compressed or decompressed length btw? We could as well make it return a negative value when a failure occurs if you feel more comfortable with it. -- Michael
20150105_fpw_compression_v13.tar.gz
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