Most callers of strerror() are removed from the backend code. The
remaining callers require special handling with a saved errno from a
previous system call. The frontend code still needs strerror() where
error states need to be handled outside of fprintf.
Note that pg_regress is not changed to use %m as the TAP output may
clobber errno, since those functions call fprintf() and friends before
evaluating the format string.
Support for %m in src/port/snprintf.c has been added in d6c55de1f9,
hence all the stable branches currently supported include it.
Author: Dagfinn Ilmari Mannsåker
Discussion: https://postgr.es/m/87sf13jhuw.fsf@wibble.ilmari.org
Prior to the introduction of the compression API in e9960732a9, pg_dump
would use the ZLIB_IN_SIZE/ZLIB_OUT_SIZE to size input/output buffers.
Commit 0da243fed0 introduced similar constants for LZ4, but while gzip
defined both buffers to be 4kB, LZ4 used 4kB and 16kB without any clear
reasoning why that's desirable.
Furthermore, parts of the code unaware of which compression is used
(e.g. pg_backup_directory.c) continued to use ZLIB_OUT_SIZE directly.
Simplify by replacing the various constants with DEFAULT_IO_BUFFER_SIZE,
set to 4kB. The compression implementations still have an option to use
a custom value, but considering 4kB was fine for 20+ years, I find that
unlikely (and we'd probably just increase the default buffer size).
Author: Georgios Kokolatos
Reviewed-by: Tomas Vondra, Justin Pryzby
Discussion: https://postgr.es/m/33496f7c-3449-1426-d568-63f6bca2ac1f@gmail.com
After 0da243fed0 got committed, we've received a report about a compiler
warning, related to the new LZ4File_gets() function:
compress_lz4.c: In function 'LZ4File_gets':
compress_lz4.c:492:19: warning: comparison of unsigned expression in
'< 0' is always false [-Wtype-limits]
492 | if (dsize < 0)
The reason is very simple - dsize is declared as size_t, which is an
unsigned integer, and thus the check is pointless and we might fail to
notice an error in some cases (or fail in a strange way a bit later).
The warning could have been silenced by simply changing the type, but we
realized the API mostly assumes all the libraries use the same types and
report errors the same way (e.g. by returning 0 and/or negative value).
But we can't make this assumption - the gzip/lz4 libraries already
disagree on some of this, and even if they did a library added in the
future might not.
The right solution is to define what the API does, and translate the
library-specific behavior in consistent way (so that the internal errors
are not exposed to users of our compression API). So this adjusts the
data types in a couple places, so that we don't miss library errors, and
simplifies and unifies the error reporting to simply return true/false
(instead of e.g. size_t).
While at it, make sure LZ4File_open_write() does not clobber errno in
case open_func() fails.
Author: Georgios Kokolatos
Reported-by: Alexander Lakhin
Reviewed-by: Tomas Vondra, Justin Pryzby
Discussion: https://postgr.es/m/33496f7c-3449-1426-d568-63f6bca2ac1f@gmail.com
Switch pg_dump to use the Compression API, implemented by bf9aa490db.
The CompressFileHandle replaces the cfp* family of functions with a
struct of callbacks for accessing (compressed) files. This allows adding
new compression methods simply by introducing a new struct instance with
appropriate implementation of the callbacks.
Archives compressed using custom compression methods store an identifier
of the compression algorithm in their header instead of the compression
level. The header version is bumped.
Author: Georgios Kokolatos
Reviewed-by: Michael Paquier, Rachel Heaton, Justin Pryzby, Tomas Vondra
Discussion: https://postgr.es/m/faUNEOpts9vunEaLnmxmG-DldLSg_ql137OC3JYDmgrOMHm1RvvWY2IdBkv_CRxm5spCCb_OmKNk2T03TMm0fBEWveFF9wA1WizPuAgB7Ss%3D%40protonmail.com
Michael Paquier
Bruce Momjian
Tomas Vondra