When creating and initializing a logical slot, the restart_lsn is set
to the latest WAL insertion point (or the latest replay point on
standbys). Subsequently, WAL records are decoded from that point to
find the start point for extracting changes in the
DecodingContextFindStartpoint() function. Since the initial
restart_lsn could be in the middle of a transaction, the start point
must be a consistent point where we won't see the data for partial
transactions.
Previously, when not building a full snapshot, serialized snapshots
were restored, and the SnapBuild jumps to the consistent state even
while finding the start point. Consequently, the slot's restart_lsn
and confirmed_flush could be set to the middle of a transaction. This
could lead to various unexpected consequences. Specifically, there
were reports of logical decoding decoding partial transactions, and
assertion failures occurred because only subtransactions were decoded
without decoding their top-level transaction until decoding the commit
record.
To resolve this issue, the changes prevent restoring the serialized
snapshot and jumping to the consistent state while finding the start
point.
On v17 and HEAD, a flag indicating whether snapshot restores should be
skipped has been added to the SnapBuild struct, and SNAPBUILD_VERSION
has been bumpded.
On backbranches, the flag is stored in the LogicalDecodingContext
instead, preserving on-disk compatibility.
Backpatch to all supported versions.
Reported-by: Drew Callahan
Reviewed-by: Amit Kapila, Hayato Kuroda
Discussion: https://postgr.es/m/2444AA15-D21B-4CCE-8052-52C7C2DAFE5C%40amazon.com
Backpatch-through: 12
To run all tests that support running against existing server:
$ meson test --setup running
To run just the main pg_regress tests against existing server:
$ meson test --setup running regress-running/regress
To ensure the 'running' setup continues to work, test it as part of the
freebsd CI task.
Discussion: https://postgr.es/m/CAH2-Wz=XDQcmLoo7RR_i6FKQdDmcyb9q5gStnfuuQXrOGhB2sQ@mail.gmail.com
The generated resource files aren't exactly the same ones as the old
buildsystems generate. Previously "InternalName" and "OriginalFileName" were
mostly wrong / not set (despite being required), but that was hard to fix in
at least the make build. Additionally, the meson build falls back to a
"auto-generated" description when not set, and doesn't set it in a few cases -
unlikely that anybody looks at these descriptions in detail.
Author: Andres Freund <andres@anarazel.de>
Author: Nazir Bilal Yavuz <byavuz81@gmail.com>
Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Autoconf is showing its age, fewer and fewer contributors know how to wrangle
it. Recursive make has a lot of hard to resolve dependency issues and slow
incremental rebuilds. Our home-grown MSVC build system is hard to maintain for
developers not using Windows and runs tests serially. While these and other
issues could individually be addressed with incremental improvements, together
they seem best addressed by moving to a more modern build system.
After evaluating different build system choices, we chose to use meson, to a
good degree based on the adoption by other open source projects.
We decided that it's more realistic to commit a relatively early version of
the new build system and mature it in tree.
This commit adds an initial version of a meson based build system. It supports
building postgres on at least AIX, FreeBSD, Linux, macOS, NetBSD, OpenBSD,
Solaris and Windows (however only gcc is supported on aix, solaris). For
Windows/MSVC postgres can now be built with ninja (faster, particularly for
incremental builds) and msbuild (supporting the visual studio GUI, but
building slower).
Several aspects (e.g. Windows rc file generation, PGXS compatibility, LLVM
bitcode generation, documentation adjustments) are done in subsequent commits
requiring further review. Other aspects (e.g. not installing test-only
extensions) are not yet addressed.
When building on Windows with msbuild, builds are slower when using a visual
studio version older than 2019, because those versions do not support
MultiToolTask, required by meson for intra-target parallelism.
The plan is to remove the MSVC specific build system in src/tools/msvc soon
after reaching feature parity. However, we're not planning to remove the
autoconf/make build system in the near future. Likely we're going to keep at
least the parts required for PGXS to keep working around until all supported
versions build with meson.
Some initial help for postgres developers is at
https://wiki.postgresql.org/wiki/Meson
With contributions from Thomas Munro, John Naylor, Stone Tickle and others.
Author: Andres Freund <andres@anarazel.de>
Author: Nazir Bilal Yavuz <byavuz81@gmail.com>
Author: Peter Eisentraut <peter@eisentraut.org>
Reviewed-By: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Discussion: https://postgr.es/m/20211012083721.hvixq4pnh2pixr3j@alap3.anarazel.de
