Commit 5ef1eefd76, which added
archive_library, purged most mentions of archive_command from the
documentation. This is inappropriate, since archive_command is still
a feature in use and users will want to see information about it.
This restores all the removed mentions and rephrases things so that
archive_command and archive_library are presented as alternatives of
each other.
Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Discussion: https://www.postgresql.org/message-id/9366d634-a917-85a9-4991-b2a4859edaf9@enterprisedb.com
In pg_receivewal, compressed output is only flushed on clean exits. The
reason to support SIGTERM as well as SIGINT (which is currently handled)
is that pg_receivewal might well be running as a daemon, and systemd's
default KillSignal is SIGTERM.
Since pg_recvlogical is also supposed to run as a daemon, teach it about
SIGTERM as well and update the documentation to match. While in there,
change pg_receivewal's time_to_stop to be sig_atomic_t like it is in
pg_recvlogical.
Author: Christoph Berg <myon@debian.org>
Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/Yvo/5No5S0c4EFMj@msg.df7cb.de
Since babbbb5 and the introduction of LZ4 in pg_receivewal, the
compression of the WAL archived is controlled by two options:
- --compression-method with "gzip", "none" or "lz4" as possible value.
- --compress=N to specify a compression level. This includes a
backward-incompatible change where a value of 0 leads to a failure
instead of no compression enforced.
This commit takes advantage of a4b5754 and 3603f7c to rework the
compression options of pg_receivewal, as of:
- The removal of --compression-method.
- The extenction of --compress to use the same grammar as pg_basebackup,
with a METHOD:DETAIL format, where a METHOD is "gzip", "none" or "lz4"
and a DETAIL is a comma-separated list of options, the only keyword
supported is now "level" to control the compression level. If only an
integer is specified as value of this option, "none" is implied on 0
and "gzip" is implied otherwise. This brings back --compress to be
backward-compatible with ~14, while still supporting LZ4.
This has also the advantage of centralizing the set of checks used by
pg_receivewal to validate its compression options.
Author: Michael Paquier
Reviewed-by: Robert Haas, Georgios Kokolatos
Discussion: https://postgr.es/m/YlPQGNAAa04raObK@paquier.xyz
Running a shell command for each file to be archived has a lot of
overhead and may not offer as much error checking as you want, or the
exact semantics that you want. So, offer the option to call a loadable
module for each file to be archived, rather than running a shell command.
Also, add a 'basic_archive' contrib module as an example implementation
that archives to a local directory.
Nathan Bossart, with a little bit of kibitzing by me.
Discussion: http://postgr.es/m/20220202224433.GA1036711@nathanxps13
This fixes a set of issues that have accumulated over the past months
(or years) in various code areas. Most fixes are related to some recent
additions, as of the development of v15.
Author: Justin Pryzby
Discussion: https://postgr.es/m/20220124030001.GQ23027@telsasoft.com
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
The option name was incorrect in one of the error messages, and the
short option 'I' was used in the code but we did not intend things to be
this way. While on it, fix the documentation to refer to a "method",
and not a "level.
Oversights in commit d62bcc8, that I have detected after more review of
the LZ4 patch for pg_receivewal.
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
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 documentation was imprecise about the starting LSN used for WAL
streaming if nothing can be found in the local archive directory
defined with the pg_receivewal command, so be more talkative on this
matter.
Extracted from a larger patch by the same author.
Author: Ronan Dunklau, Michael Paquier
Discussion: https://postgr.es/m/18708360.4lzOvYHigE@aivenronan
Backpatch-through: 10
The following docs are updated:
- High-availaility section
- pg_basebackup
- pg_receivewal
Per the principle of least privilege, we want to encourage users to
interact with those areas using roles that have replication rights, but
superusers were mentioned first.
Author: Daniel Gustafsson
Reviewed-by: Fujii Masao, Michael Paquier
Discussion: https://postgr.es/m/ECEBD212-7101-41EB-84F3-2F356E4B6401@yesql.se
This addresses a couple of issues in the documentation:
- Description of PG_COLOR was missing for some tools (pg_archivecleanup
and pg_test_fsync), while the other descriptions had grammar mistakes.
- pgbench supports more environment variables: PGUSER, PGHOST and
PGPORT.
- vacuumlo, oid2name and pgbench support coloring (HEAD only)
Author: Michael Paquier
Reviewed-by: Fabien Coelho, Daniel Gustafsson, Juan José Santamaría
Flecha
Discussion: https://postgr.es/m/20200304075418.GJ2593@paquier.xyz
Backpatch-through: 12
Using pg_receivewal with synchronous_commit = remote_apply set in the
backend is incompatible if pg_receivewal is a synchronous standby as it
never applies WAL, so document this problem and solutions to it.
Backpatch to 9.6, where remote_apply has been added.
Author: Robert Haas, Jesper Pedersen
Reviewed-by: Laurenz Albe, Álvaro Herrera, Michael Paquier
Discussion: https://postgr.es/m/1427a2d3-1e51-9335-1931-4f8853d90d5e@redhat.com
Backpatch-through: 9.6
This unifies the various ad hoc logging (message printing, error
printing) systems used throughout the command-line programs.
Features:
- Program name is automatically prefixed.
- Message string does not end with newline. This removes a common
source of inconsistencies and omissions.
- Additionally, a final newline is automatically stripped, simplifying
use of PQerrorMessage() etc., another common source of mistakes.
- I converted error message strings to use %m where possible.
- As a result of the above several points, more translatable message
strings can be shared between different components and between
frontends and backend, without gratuitous punctuation or whitespace
differences.
- There is support for setting a "log level". This is not meant to be
user-facing, but can be used internally to implement debug or
verbose modes.
- Lazy argument evaluation, so no significant overhead if logging at
some level is disabled.
- Some color in the messages, similar to gcc and clang. Set
PG_COLOR=auto to try it out. Some colors are predefined, but can be
customized by setting PG_COLORS.
- Common files (common/, fe_utils/, etc.) can handle logging much more
simply by just using one API without worrying too much about the
context of the calling program, requiring callbacks, or having to
pass "progname" around everywhere.
- Some programs called setvbuf() to make sure that stderr is
unbuffered, even on Windows. But not all programs did that. This
is now done centrally.
Soft goals:
- Reduces vertical space use and visual complexity of error reporting
in the source code.
- Encourages more deliberate classification of messages. For example,
in some cases it wasn't clear without analyzing the surrounding code
whether a message was meant as an error or just an info.
- Concepts and terms are vaguely aligned with popular logging
frameworks such as log4j and Python logging.
This is all just about printing stuff out. Nothing affects program
flow (e.g., fatal exits). The uses are just too varied to do that.
Some existing code had wrappers that do some kind of print-and-exit,
and I adapted those.
I tried to keep the output mostly the same, but there is a lot of
historical baggage to unwind and special cases to consider, and I
might not always have succeeded. One significant change is that
pg_rewind used to write all error messages to stdout. That is now
changed to stderr.
Reviewed-by: Donald Dong <xdong@csumb.edu>
Reviewed-by: Arthur Zakirov <a.zakirov@postgrespro.ru>
Discussion: https://www.postgresql.org/message-id/flat/6a609b43-4f57-7348-6480-bd022f924310@2ndquadrant.com
Allow the cluster to be optionally init'd with read access for the
group.
This means a relatively non-privileged user can perform a backup of the
cluster without requiring write privileges, which enhances security.
The mode of PGDATA is used to determine whether group permissions are
enabled for directory and file creates. This method was chosen as it's
simple and works well for the various utilities that write into PGDATA.
Changing the mode of PGDATA manually will not automatically change the
mode of all the files contained therein. If the user would like to
enable group access on an existing cluster then changing the mode of all
the existing files will be required. Note that pg_upgrade will
automatically change the mode of all migrated files if the new cluster
is init'd with the -g option.
Tests are included for the backend and all the utilities which operate
on the PG data directory to ensure that the correct mode is set based on
the data directory permissions.
Author: David Steele <david@pgmasters.net>
Reviewed-By: Michael Paquier, with discussion amongst many others.
Discussion: https://postgr.es/m/ad346fe6-b23e-59f1-ecb7-0e08390ad629%40pgmasters.net
Since some preparation work had already been done, the only source
changes left were changing empty-element tags like <xref linkend="foo">
to <xref linkend="foo"/>, and changing the DOCTYPE.
The source files are still named *.sgml, but they are actually XML files
now. Renaming could be considered later.
In the build system, the intermediate step to convert from SGML to XML
is removed. Everything is build straight from the source files again.
The OpenSP (or the old SP) package is no longer needed.
The documentation toolchain instructions are updated and are much
simpler now.
Peter Eisentraut, Alexander Lakhin, Jürgen Purtz
IDs in SGML are case insensitive, and we have accumulated a mix of upper
and lower case IDs, including different variants of the same ID. In
XML, these will be case sensitive, so we need to fix up those
differences. Going to all lower case seems most straightforward, and
the current build process already makes all anchors and lower case
anyway during the SGML->XML conversion, so this doesn't create any
difference in the output right now. A future XML-only build process
would, however, maintain any mixed case ID spellings in the output, so
that is another reason to clean this up beforehand.
Author: Alexander Lakhin <exclusion@gmail.com>
For DocBook XML compatibility, don't use SGML empty tags (</>) anymore,
replace by the full tag name. Add a warning option to catch future
occurrences.
Alexander Lakhin, Jürgen Purtz
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>
