This new view, wrapped around a SRF, shows some information known about
wait events, as of:
- Name.
- Type (Activity, I/O, Extension, etc.).
- Description.
All the information retrieved comes from wait_event_names.txt, and the
description is the same as the documentation with filters applied to
remove any XML markups. This view is useful when joined with
pg_stat_activity to get the description of a wait event reported.
Custom wait events for extensions are included in the view.
Original idea by Yves Colin.
Author: Bertrand Drouvot
Reviewed-by: Kyotaro Horiguchi, Masahiro Ikeda, Tom Lane, Michael
Paquier
Discussion: https://postgr.es/m/0e2ae164-dc89-03c3-cf7f-de86378053ac@gmail.com
The documentation and the code is generated automatically from a new
file called wait_event_names.txt, formatted in sections dedicated to
each wait event class (Timeout, Lock, IO, etc.) with three tab-separated
fields:
- C symbol in enums
- Format in the system views
- Description in the docs
Using this approach has several advantages, as we have proved to be
rather bad in maintaining this area of the tree across the years:
- The order of each item in the documentation and the code, which should
be alphabetical, has become incorrect multiple times, and the script
generating the code and documentation has a few rules to enforce that,
making the maintenance a no-brainer.
- Some wait events were added to the code, but not documented, so this
cannot be missed now.
- The order of the tables for each wait event class is enforced in the
documentation (the input .txt file does so as well for clarity, though
this is not mandatory).
- Less code, shaving 1.2k lines from the tree, with 1/3 of the savings
coming from the code, the rest from the documentation.
The wait event types "Lock" and "LWLock" still have their own code path
for their code, hence only the documentation is created for them. These
classes are listed with a special marker called WAIT_EVENT_DOCONLY in
the input file.
Adding a new wait event now requires only an update of
wait_event_names.txt, with "Lock" and "LWLock" treated as exceptions.
This commit has been tested with configure/Makefile, the CI and VPATH
build. clean, distclean and maintainer-clean were working fine.
Author: Bertrand Drouvot, Michael Paquier
Discussion: https://postgr.es/m/77a86b3a-c4a8-5f5d-69b9-d70bbf2e9b98@gmail.com
This commit adds the infrastructure for more detailed IO statistics. The calls
to actually count IOs, a system view to access the new statistics,
documentation and tests will be added in subsequent commits, to make review
easier.
While we already had some IO statistics, e.g. in pg_stat_bgwriter and
pg_stat_database, they did not provide sufficient detail to understand what
the main sources of IO are, or whether configuration changes could avoid
IO. E.g., pg_stat_bgwriter.buffers_backend does contain the number of buffers
written out by a backend, but as that includes extending relations (always
done by backends) and writes triggered by the use of buffer access strategies,
it cannot easily be used to tune background writer or checkpointer. Similarly,
pg_stat_database.blks_read cannot easily be used to tune shared_buffers /
compute a cache hit ratio, as the use of buffer access strategies will often
prevent a large fraction of the read blocks to end up in shared_buffers.
The new IO statistics count IO operations (evict, extend, fsync, read, reuse,
and write), and are aggregated for each combination of backend type (backend,
autovacuum worker, bgwriter, etc), target object of the IO (relations, temp
relations) and context of the IO (normal, vacuum, bulkread, bulkwrite).
What is tracked in this series of patches, is sufficient to perform the
aforementioned analyses. Further details, e.g. tracking the number of buffer
hits, would make that even easier, but was left out for now, to keep the scope
of the already large patchset manageable.
Bumps PGSTAT_FILE_FORMAT_ID.
Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://postgr.es/m/20200124195226.lth52iydq2n2uilq@alap3.anarazel.de
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
Bruce Momjian
Michael Paquier
Andres Freund
Andrew Dunstan