pg_receivewal gains a new option, --compression-method=lz4, available
when the code is compiled with --with-lz4. Similarly to gzip, this
gives the possibility to compress archived WAL segments with LZ4. This
option is not compatible with --compress.
The implementation uses LZ4 frames, and is compatible with simple lz4
commands. Like gzip, using --synchronous ensures that any data will be
flushed to disk within the current .partial segment, so as it is
possible to retrieve as much WAL data as possible even from a
non-completed segment (this requires completing the partial file with
zeros up to the WAL segment size supported by the backend after
decompression, but this is the same as gzip).
The calculation of the streaming start LSN is able to transparently find
and check LZ4-compressed segments. Contrary to gzip where the
uncompressed size is directly stored in the object read, the LZ4 chunk
protocol does not store the uncompressed data by default. There is
contentSize that can be used with LZ4 frames by that would not help if
using an archive that includes segments compressed with the defaults of
a "lz4" command, where this is not stored. So, this commit has taken
the most extensible approach by decompressing the already-archived
segment to check its uncompressed size, through a blank output buffer in
chunks of 64kB (no actual performance difference noticed with 8kB, 16kB
or 32kB, and the operation in itself is actually fast).
Tests have been added to verify the creation and correctness of the
generated LZ4 files. The latter is achieved by the use of command
"lz4", if found in the environment.
The tar-based WAL method in walmethods.c, used now only by
pg_basebackup, does not know yet about LZ4. Its code could be extended
for this purpose.
Author: Georgios Kokolatos
Reviewed-by: Michael Paquier, Jian Guo, Magnus Hagander, Dilip Kumar
Discussion: https://postgr.es/m/ZCm1J5vfyQ2E6dYvXz8si39HQ2gwxSZ3IpYaVgYa3lUwY88SLapx9EEnOf5uEwrddhx2twG7zYKjVeuP5MwZXCNPybtsGouDsAD1o2L_I5E=@pm.me
pg_receivewal includes since cada1af the option --compress, to allow the
compression of WAL segments using gzip, with a value of 0 (the default)
meaning that no compression can be used.
This commit introduces a new option, called --compression-method, able
to use as values "none", the default, and "gzip", to make things more
extensible. The case of --compress=0 becomes fuzzy with this option
layer, so we have made the choice to make pg_receivewal return an error
when using "none" and a non-zero compression level, meaning that the
authorized values of --compress are now [1,9] instead of [0,9]. Not
specifying --compress with "gzip" as compression method makes
pg_receivewal use the default of zlib instead (Z_DEFAULT_COMPRESSION).
The code in charge of finding the streaming start LSN when scanning the
existing archives is refactored and made more extensible. While on it,
rename "compression" to "compression_level" in walmethods.c, to reduce
the confusion with the introduction of the compression method, even if
the tar method used by pg_basebackup does not rely on the compression
method (yet, at least), but just on the compression level (this area
could be improved more, actually).
This is in preparation for an upcoming patch that adds LZ4 support to
pg_receivewal.
Author: Georgios Kokolatos
Reviewed-by: Michael Paquier, Jian Guo, Magnus Hagander, Dilip Kumar,
Robert Haas
Discussion: https://postgr.es/m/ZCm1J5vfyQ2E6dYvXz8si39HQ2gwxSZ3IpYaVgYa3lUwY88SLapx9EEnOf5uEwrddhx2twG7zYKjVeuP5MwZXCNPybtsGouDsAD1o2L_I5E=@pm.me
pg_receivewal is able to follow a timeline switch, but this was not
tested. This test uses an empty archive location with a restart done
from a slot, making its implementation a tad simpler than if we would
reuse an existing archive directory.
Author: Ronan Dunklau
Reviewed-by: Kyotaro Horiguchi, Michael Paquier
Discussion: https://postgr.es/m/18708360.4lzOvYHigE@aivenronan
This commit improves the speed of those tests by 25~30%, using some
simple ideas to reduce the amount of data written by pg_receivewal:
- Use a segment size of 1MB. While reducing the amount of data zeroed
by pg_receivewal for the new segments, this improves the code coverage
with a non-default segment size.
- In the last test involving a slot's restart_lsn, generate a checkpoint
to advance the redo LSN and the WAL retained by the slot created,
reducing the number of segments that need to be archived. This counts
for most of the gain.
- Minimize the amount of data inserted into the dummy table.
Reviewed-by: Ronan Dunklau
Discussion: https://postgr.es/m/YXqYKAdVEqmyTltK@paquier.xyz
Prior to this patch, when running pg_receivewal, the streaming start
point would be the current location of the archives if anything is
found in the local directory where WAL segments are written, and
pg_receivewal would fall back to the current WAL flush location if there
are no archives, as of the result of an IDENTIFY_SYSTEM command.
If for some reason the WAL files from pg_receivewal were moved, it is
better to try a restart where we left at, which is the replication
slot's restart_lsn instead of skipping right to the current flush
location, to avoid holes in the WAL backed up. This commit changes
pg_receivewal to use the following sequence of methods to determine the
starting streaming LSN:
- Scan the local archives.
- Use the slot's restart_lsn, if supported by the backend and if a slot
is defined.
- Fallback to the current flush LSN as reported by IDENTIFY_SYSTEM.
To keep compatibility with older server versions, we only attempt to use
READ_REPLICATION_SLOT if the backend version is at least 15, and
fallback to the older behavior of streaming from the current flush
LSN if the command is not supported.
Some TAP tests are added to cover this feature.
Author: Ronan Dunklau
Reviewed-by: Kyotaro Horiguchi, Michael Paquier, Bharath Rupireddy
Discussion: https://postgr.es/m/18708360.4lzOvYHigE@aivenronan
The five modules in our TAP test framework all had names in the top
level namespace. This is unwise because, even though we're not
exporting them to CPAN, the names can leak, for example if they are
exported by the RPM build process. We therefore move the modules to the
PostgreSQL::Test namespace. In the process PostgresNode is renamed to
Cluster, and TestLib is renamed to Utils. PostgresVersion becomes simply
PostgreSQL::Version, to avoid possible confusion about what it's the
version of.
Discussion: https://postgr.es/m/aede93a4-7d92-ef26-398f-5094944c2504@dunslane.net
Reviewed by Erik Rijkers and Michael Paquier
This reverts commit 6a2c532. fairywren and bowerbird failed those tests
because of incorrect versions of ZLIB linked to, causing errors like
SIGBREAKs that stopped buildfarm runs or EACCES failures when writing
compressed WAL segments.
Andrew Dunstan has done all the investigation here, so he deserves all
the credit for being able to enable those tests on Windows.
Discussion: https://postgr.es/m/9040d5ed-6462-66a4-07ac-2923785ae563@dunslane.net
Those tests are not designed to fail, but if they do, like on some cases
for Windows because of ZLIB (?), they could remain stuck. Using
--no-loop makes the test fail immediately. The oldest test with
--endpos already did that.
Those tests have been added in ffc9dda.
Reviewed-by: Andrew Dunstan
Discussion: https://postgr.es/m/ec093ff1-a53c-0091-46a2-4537354b0dd4@dunslane.net
There is only one constructor now for PostgresNode, with the idiomatic
name 'new'. The method is not exported by the class, and must be called
as "PostgresNode->new('name',[args])". All the TAP tests that use
PostgresNode are modified accordingly. Third party scripts will need
adjusting, which is a fairly mechanical process (I just used a sed
script).
A check in the ZLIB portion of the test to match the name of a
non-compressed partial segment with a completed compressed segment was
using m//, while a simple equality check is enough. This makes the test
a bit stricter without impacting its coverage.
Author: Kyotaro Horiguchi
Discussion: https://postgr.es/m/20210726.174622.826565852378770261.horikyota.ntt@gmail.com
strtoint(), via strtol(), would skip leading whitespaces but the same
rule was not applied for trailing whitespaces, leading to an
inconsistent behavior. Some tests are changed to cover more this area.
Author: Michael Paquier
Reviewed-by: Kyotaro Horiguchi
Discussion: https://postgr.es/m/YP5Pv0d13Ct+03ve@paquier.xyz
This reverts commit 91d395f, to avoid running those tests on Windows.
The tests are globally stable across all buildfarm members, except
fairywren (crash of pg_receivewal) and bowerdird (SIGBREAK preventing
the buildfarm run to complete). Those errors are rather strange, as
other hosts with very similar characteristics are able to run those
tests without breaking a sweat.
For now, disable those tests on Windows to turn back the buildfarm to
green.
Per discussion with Andrew Dunstan.
Discussion: https://postgr.es/m/9040d5ed-6462-66a4-07ac-2923785ae563@dunslane.net
This is a revert of 6cea447, that disabled those tests temporarily on
Windows due to failures with bowerbird where gzflush() would fail when
executed on a freshly-opened compressed and partial segment. This
problem should be taken care of now thanks to 7fbe0c8, so let's see what
the buildfarm has to say on Windows for those tests.
Discussion: https://postgr.es/m/YPDLz2x3o1aX2wRh@paquier.xyz
As reported by buildfarm member bowerbird, those tests are unstable on
Windows. The failure produced there points to a problem with gzflush(),
that fails to sync a file freshly-opened, with a gzFile properly
opened. While testing this myself with MSVC, I bumped into a different
error where a file could simply not be opened, so this makes me rather
doubtful that testing this area on Windows is a good idea if this
finishes with random concurrency failures. This requires more
investigation, and keeping this buildfarm member red is not a good thing
in the long-term, so for now this just disables this set of tests on
Windows.
Discussion: https://postgr.es/m/YPDLz2x3o1aX2wRh@paquier.xyz
The OpenBSD implementation of gzip considers only files suffixed by "Z",
"gz", "z", "tgz" or "taz" as valid targets, discarding anything else and
making a command using --test exit with an error code of 512 if anything
invalid is found. The test introduced in ffc9dda tested a WAL segment
suffixed as .gz.partial, enough to make the test fail.
Testing only a full segment is fine enough in terms of coverage, so
simplify the code by discarding the .gz.partial segment in this check.
This should be enough to make the test pass with OpenBSD environments.
Per report from curculio.
Discussion: https://postgr.es/m/YPAdf9r5aJbDoHoq@paquier.xyz
There is a non-trivial amount of code that handles ZLIB compression in
pg_receivewal, from basics like the format name, the calculation of the
start streaming position and of course the compression itself, but there
was no automated coverage for it.
This commit introduces a set of conditional tests (if the build supports
ZLIB) to cover the creation of ZLIB-compressed WAL segments, the
handling of the partial, compressed, WAL segments and the compression
operation in itself. Note that there is an extra phase checking the
validity of the generated files by using directly a gzip command, passed
down by the Makefile of pg_receivewal. This part is skipped if the
command cannot be found, something likely going to happen on Windows
with MSVC except if one sets the variable GZIP_PROGRAM in the
environment of the test.
This set of tests will become handy for upcoming patches that add more
options for the compression methods used by pg_receivewal, like LZ4, to
make sure that no existing facilities are broken.
Author: Georgios Kokolatos
Reviewed-by: Gilles Darold, Michael Paquier
Discussion: https://postgr.es/m/07BK3Mk5aEOsTwGaY77qBVyf9GjoEzn8TMgHLyPGfEFPIpTEmoQuP2P4c7teesjSg-LPeUafsp1flnPeQYINMSMB_UpggJDoduB5EDYBqaQ=@protonmail.com
The vertical tightness settings collapse vertical whitespace between
opening and closing brackets (parentheses, square brakets and braces).
This can make data structures in particular harder to read, and is not
very consistent with our style in non-Perl code. This patch restricts
that setting to parentheses only, and reformats all the perl code
accordingly. Not applying this to parentheses has some unfortunate
effects, so the consensus is to keep the setting for parentheses and not
for the others.
The diff for this patch does highlight some places where structures
should have trailing commas. They can be added manually, as there is no
automatic tool to do so.
Discussion: https://postgr.es/m/a2f2b87c-56be-c070-bfc0-36288b4b41c1@2ndQuadrant.com
Consolidate directory and file create permissions for tools which work
with the PG data directory by adding a new module (common/file_perm.c)
that contains variables (pg_file_create_mode, pg_dir_create_mode) and
constants to initialize them (0600 for files and 0700 for directories).
Convert mkdir() calls in the backend to MakePGDirectory() if the
original call used default permissions (always the case for regular PG
directories).
Add tests to make sure permissions in PGDATA are set correctly by the
tools which modify the PG data directory.
Authors: David Steele <david@pgmasters.net>,
Adam Brightwell <adam.brightwell@crunchydata.com>
Reviewed-By: Michael Paquier, with discussion amongst many others.
Discussion: https://postgr.es/m/ad346fe6-b23e-59f1-ecb7-0e08390ad629%40pgmasters.net
Add some more tests for the --create-slot and --drop-slot options,
verifying that the right kind of slot was created and that the slot was
dropped. While working on an unrelated patch for pg_basebackup, some of
this was temporarily broken without any tests noticing.
This is primarily useful for making tests of this utility more
deterministic, to avoid the complexity of starting pg_receivewal as a
deamon in TAP tests.
While this is less useful than the equivalent pg_recvlogical option,
users can as well use it for example to enforce WAL streaming up to a
end-of-backup position, to save only a minimal amount of WAL.
Use this new option to stream WAL data in a deterministic way within a
new set of TAP tests.
Author: Michael Paquier <michael.paquier@gmail.com>
Michael Paquier
Andrew Dunstan
Tom Lane
Stephen Frost
Robert Haas
Peter Eisentraut