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Robert Haas 23a1c6578c Introduce 'bbstreamer' abstraction to modularize pg_basebackup.
pg_basebackup knows how to do quite a few things with a backup that it
gets from the server, like just write out the files, or compress them
first, or even parse the tar format and inject a modified
postgresql.auto.conf file into the archive generated by the server.
Unforatunely, this makes pg_basebackup.c a very large source file, and
also somewhat difficult to enhance, because for example the knowledge
that the server is sending us a 'tar' file rather than some other sort
of archive is spread all over the place rather than centralized.

In an effort to improve this situation, this commit invents a new
'bbstreamer' abstraction. Each archive received from the server is
fed to a bbstreamer which may choose to dispose of it or pass it
along to some other bbstreamer. Chunks may also be "labelled"
according to whether they are part of the payload data of a file
in the archive or part of the archive metadata.

So, for example, if we want to take a tar file, modify the
postgresql.auto.conf file it contains, and the gzip the result
and write it out, we can use a bbstreamer_tar_parser to parse the
tar file received from the server, a bbstreamer_recovery_injector
to modify the contents of postgresql.auto.conf, a
bbstreamer_tar_archiver to replace the tar headers for the file
modified in the previous step with newly-built ones that are
correct for the modified file, and a bbstreamer_gzip_writer to
gzip and write the resulting data. Only the objects with "tar"
in the name know anything about the tar archive format, and in
theory we could re-archive using some other format rather than
"tar" if somebody wanted to write the code.

These chances do add a substantial amount of code, but I think the
result is a lot more maintainable and extensible. pg_basebackup.c
itself shrinks by roughly a third, with a lot of the complexity
previously contained there moving into the newly-added files.

Patch by me. The larger patch series of which this is a part has been
reviewed and tested at various times by Andres Freund, Sumanta
Mukherjee, Dilip Kumar, Suraj Kharage, Dipesh Pandit, Tushar Ahuja,
Mark Dilger, Sergei Kornilov, and Jeevan Ladhe.

Discussion: https://postgr.es/m/CA+TgmoZGwR=ZVWFeecncubEyPdwghnvfkkdBe9BLccLSiqdf9Q@mail.gmail.com
Discussion: https://postgr.es/m/CA+TgmoZvqk7UuzxsX1xjJRmMGkqoUGYTZLDCH8SmU1xTPr1Xig@mail.gmail.com
2021-11-05 10:26:18 -04:00
config Adjust configure to insist on Perl version >= 5.8.3. 2021-10-07 14:26:17 -04:00
contrib amcheck: Add additional TOAST pointer checks. 2021-11-05 09:24:25 -04:00
doc Reword doc blurb for vacuumdb --analyze-in-stages 2021-11-05 11:22:30 -03:00
src Introduce 'bbstreamer' abstraction to modularize pg_basebackup. 2021-11-05 10:26:18 -04:00
.dir-locals.el
.editorconfig
.git-blame-ignore-revs Add another old commit to git-blame-ignore-revs. 2021-11-03 17:34:19 -07:00
.gitattributes gitattributes: Add new entry to silence whitespace error 2021-06-05 07:57:31 +02:00
.gitignore
aclocal.m4
configure Make configure check for minimum required version of IPC::Run. 2021-10-11 16:49:49 -04:00
configure.ac Make configure check for minimum required version of IPC::Run. 2021-10-11 16:49:49 -04:00
COPYRIGHT Update copyright for 2021 2021-01-02 13:06:25 -05:00
GNUmakefile.in add missing tag from commit b8c4261e5e 2021-07-01 15:47:46 -04:00
HISTORY
Makefile
README
README.git

PostgreSQL Database Management System
=====================================

This directory contains the source code distribution of the PostgreSQL
database management system.

PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
transactions, foreign keys, subqueries, triggers, user-defined types
and functions.  This distribution also contains C language bindings.

PostgreSQL has many language interfaces, many of which are listed here:

	https://www.postgresql.org/download/

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
hardware platforms and contains information regarding any other
software packages that are required to build or run the PostgreSQL
system.  Copyright and license information can be found in the
file COPYRIGHT.  A comprehensive documentation set is included in this
distribution; it can be read as described in the installation
instructions.

The latest version of this software may be obtained at
https://www.postgresql.org/download/.  For more information look at our
web site located at https://www.postgresql.org/.