This adds a new variable-numbered statistics kind in pgstats, where the
object ID key of the stats entries is based on the proc number of the
backends. This acts as an upper-bound for the number of stats entries
that can exist at once. The entries are created when a backend starts
after authentication succeeds, and are removed when the backend exits,
making the stats entry exist for as long as their backend is up and
running. These are not written to the pgstats file at shutdown (note
that write_to_file is disabled, as a safety measure).
Currently, these stats include only information about the I/O generated
by a backend, using the same layer as pg_stat_io, except that it is now
possible to know how much activity is happening in each backend rather
than an overall aggregate of all the activity. A function called
pg_stat_get_backend_io() is added to access this data depending on the
PID of a backend. The existing structure could be expanded in the
future to add more information about other statistics related to
backends, depending on requirements or ideas.
Auxiliary processes are not included in this set of statistics. These
are less interesting to have than normal backends as they have dedicated
entries in pg_stat_io, and stats kinds of their own.
This commit includes also pg_stat_reset_backend_stats(), function able
to reset all the stats associated to a single backend.
Bump catalog version and PGSTAT_FILE_FORMAT_ID.
Author: Bertrand Drouvot
Reviewed-by: Álvaro Herrera, Kyotaro Horiguchi, Michael Paquier, Nazir
Bilal Yavuz
Discussion: https://postgr.es/m/ZtXR+CtkEVVE/LHF@ip-10-97-1-34.eu-west-3.compute.internal
This commit adds pg_stat_io_build_tuples(), a helper routine for
pg_stat_get_io(), that fills its result tuplestore based on the contents
of PgStat_BktypeIO. This will be used in a follow-up commit that uses
the same structures as pg_stat_io for reporting, including the same
object types and contexts, but for a different statistics kind.
Author: Bertrand Drouvot, Michael Paquier
Discussion: https://postgr.es/m/ZtXR+CtkEVVE/LHF@ip-10-97-1-34.eu-west-3.compute.internal
There are a few places in this file that use memset() and memcmp()
to determine whether a section of memory is all zeros. This commit
modifies them to use pg_memory_is_all_zeros() instead. These
aren't expected to be hot code paths, but this may optimize them a
bit. Plus, this allows us to remove some variables that were only
needed for the memset() and memcmp().
Author: Bertrand Drouvot
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/Z1hNubHfvMxlW6eu%40ip-10-97-1-34.eu-west-3.compute.internal
Two attributes are added to pg_stat_database:
* parallel_workers_to_launch, counting the total number of parallel
workers that were planned to be launched.
* parallel_workers_launched, counting the total number of parallel
workers actually launched.
The ratio of both fields can provide hints that there are not enough
slots available when launching parallel workers, also useful when
pg_stat_statements is not deployed on an instance (i.e. cf54a2c002).
This commit relies on de3a2ea3b2, that has added two fields to EState,
that get incremented when executing Gather or GatherMerge nodes.
A test is added in select_parallel, where parallel workers are spawned.
Bump catalog version.
Author: Benoit Lobréau
Discussion: https://postgr.es/m/783bc7f7-659a-42fa-99dd-ee0565644e25@dalibo.com
Previously, the pg_stat_checkpointer view and the checkpoint completion
log message could show different numbers for buffers written
during checkpoints. The view only counted shared buffers,
while the log message included both shared and SLRU buffers,
causing inconsistencies.
This commit resolves the issue by updating both the view and the log message
to separately report shared and SLRU buffers written during checkpoints.
A new slru_written column is added to the pg_stat_checkpointer view
to track SLRU buffers, while the existing buffers_written column now
tracks only shared buffers. This change would help users distinguish
between the two types of buffers, in the pg_stat_checkpointer view and
the checkpoint complete log message, respectively.
Bump catalog version.
Author: Nitin Jadhav
Reviewed-by: Bharath Rupireddy, Michael Paquier, Kyotaro Horiguchi, Robert Haas
Reviewed-by: Andres Freund, vignesh C, Fujii Masao
Discussion: https://postgr.es/m/CAMm1aWb18EpT0whJrjG+-nyhNouXET6ZUw0pNYYAe+NezpvsAA@mail.gmail.com
Checkpoints can be skipped when the server is idle. The existing num_timed and
num_requested counters in pg_stat_checkpointer track both completed and
skipped checkpoints, but there was no way to count only the completed ones.
This commit introduces the num_done counter, which tracks only completed
checkpoints, making it easier to see how many were actually performed.
Bump catalog version.
Author: Anton A. Melnikov
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/9ea77f40-818d-4841-9dee-158ac8f6e690@oss.nttdata.com
This opens the possibility to define keys for more types of statistics
kinds in PgStat_HashKey, the first case being 8-byte query IDs for
statistics like pg_stat_statements.
This increases the size of PgStat_HashKey from 12 to 16 bytes, while
PgStatShared_HashEntry, entry stored in the dshash for pgstats, keeps
the same size due to alignment.
xl_xact_stats_item, that tracks the stats items to drop in commit WAL
records, is increased from 12 to 16 bytes. Note that individual chunks
in commit WAL records should be multiples of sizeof(int), hence 8-byte
object IDs are stored as two uint32, based on a suggestion from Heikki
Linnakangas.
While on it, the field of PgStat_HashKey is renamed from "objoid" to
"objid", as for some stats kinds this field does not refer to OIDs but
just IDs, like for replication slot stats.
This commit bumps the following format variables:
- PGSTAT_FILE_FORMAT_ID, as PgStat_HashKey is written to the stats file
for non-serialized stats kinds in the dshash table.
- XLOG_PAGE_MAGIC for the changes in xl_xact_stats_item.
- Catalog version, for the SQL function pg_stat_have_stats().
Reviewed-by: Bertrand Drouvot
Discussion: https://postgr.es/m/ZsvTS9EW79Up8I62@paquier.xyz
pg_stat_get_io() applied TimestampTzGetDatum twice to the
stat_reset_timestamp value. On 64-bit builds that's harmless because
TimestampTzGetDatum is a no-op, but on 32-bit builds it results in
displaying garbage in the stats_reset column of the pg_stat_io view.
Bug dates to commit a9c70b46d which introduced pg_stat_io, so
back-patch to v16 where that came in.
Bertrand Drouvot
Discussion: https://postgr.es/m/Ztrd+XcPTz1zorkg@ip-10-97-1-34.eu-west-3.compute.internal
This commit adds columns in view pg_stat_subscription_stats to show the
number of times a particular conflict type has occurred during the
application of logical replication changes. The following columns are
added:
confl_insert_exists:
Number of times a row insertion violated a NOT DEFERRABLE unique
constraint.
confl_update_origin_differs:
Number of times an update was performed on a row that was
previously modified by another origin.
confl_update_exists:
Number of times that the updated value of a row violates a
NOT DEFERRABLE unique constraint.
confl_update_missing:
Number of times that the tuple to be updated is missing.
confl_delete_origin_differs:
Number of times a delete was performed on a row that was
previously modified by another origin.
confl_delete_missing:
Number of times that the tuple to be deleted is missing.
The update_origin_differs and delete_origin_differs conflicts can be
detected only when track_commit_timestamp is enabled.
Author: Hou Zhijie
Reviewed-by: Shveta Malik, Peter Smith, Anit Kapila
Discussion: https://postgr.es/m/OS0PR01MB57160A07BD575773045FC214948F2@OS0PR01MB5716.jpnprd01.prod.outlook.com
This commit adds support in the backend for $subject, allowing
out-of-core extensions to plug their own custom kinds of cumulative
statistics. This feature has come up a few times into the lists, and
the first, original, suggestion came from Andres Freund, about
pg_stat_statements to use the cumulative statistics APIs in shared
memory rather than its own less efficient internals. The advantage of
this implementation is that this can be extended to any kind of
statistics.
The stats kinds are divided into two parts:
- The in-core "builtin" stats kinds, with designated initializers, able
to use IDs up to 128.
- The "custom" stats kinds, able to use a range of IDs from 128 to 256
(128 slots available as of this patch), with information saved in
TopMemoryContext. This can be made larger, if necessary.
There are two types of cumulative statistics in the backend:
- For fixed-numbered objects (like WAL, archiver, etc.). These are
attached to the snapshot and pgstats shmem control structures for
efficiency, and built-in stats kinds still do that to avoid any
redirection penalty. The data of custom kinds is stored in a first
array in snapshot structure and a second array in the shmem control
structure, both indexed by their ID, acting as an equivalent of the
builtin stats.
- For variable-numbered objects (like tables, functions, etc.). These
are stored in a dshash using the stats kind ID in the hash lookup key.
Internally, the handling of the builtin stats is unchanged, and both
fixed and variabled-numbered objects are supported. Structure
definitions for builtin stats kinds are renamed to reflect better the
differences with custom kinds.
Like custom RMGRs, custom cumulative statistics can only be loaded with
shared_preload_libraries at startup, and must allocate a unique ID
shared across all the PostgreSQL extension ecosystem with the following
wiki page to avoid conflicts:
https://wiki.postgresql.org/wiki/CustomCumulativeStats
This makes the detection of the stats kinds and their handling when
reading and writing stats much easier than, say, allocating IDs for
stats kinds from a shared memory counter, that may change the ID used by
a stats kind across restarts. When under development, extensions can
use PGSTAT_KIND_EXPERIMENTAL.
Two examples that can be used as templates for fixed-numbered and
variable-numbered stats kinds will be added in some follow-up commits,
with tests to provide coverage.
Some documentation is added to explain how to use this plugin facility.
Author: Michael Paquier
Reviewed-by: Dmitry Dolgov, Bertrand Drouvot
Discussion: https://postgr.es/m/Zmqm9j5EO0I4W8dx@paquier.xyz
This adds the X509 attributes notBefore and notAfter to sslinfo
as well as pg_stat_ssl to allow verifying and identifying the
validity period of the current client certificate. OpenSSL has
APIs for extracting notAfter and notBefore, but they are only
supported in recent versions so we have to calculate the dates
by hand in order to make this work for the older versions of
OpenSSL that we still support.
Original patch by Cary Huang with additional hacking by Jacob
and myself.
Author: Cary Huang <cary.huang@highgo.ca>
Co-author: Jacob Champion <jacob.champion@enterprisedb.com>
Co-author: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/182b8565486.10af1a86f158715.2387262617218380588@highgo.ca
as determined by include-what-you-use (IWYU)
While IWYU also suggests to *add* a bunch of #include's (which is its
main purpose), this patch does not do that. In some cases, a more
specific #include replaces another less specific one.
Some manual adjustments of the automatic result:
- IWYU currently doesn't know about includes that provide global
variable declarations (like -Wmissing-variable-declarations), so
those includes are being kept manually.
- All includes for port(ability) headers are being kept for now, to
play it safe.
- No changes of catalog/pg_foo.h to catalog/pg_foo_d.h, to keep the
patch from exploding in size.
Note that this patch touches just *.c files, so nothing declared in
header files changes in hidden ways.
As a small example, in src/backend/access/transam/rmgr.c, some IWYU
pragma annotations are added to handle a special case there.
Discussion: https://www.postgresql.org/message-id/flat/af837490-6b2f-46df-ba05-37ea6a6653fc%40eisentraut.org
Now that BackendId was just another index into the proc array, it was
redundant with the 0-based proc numbers used in other places. Replace
all usage of backend IDs with proc numbers.
The only place where the term "backend id" remains is in a few pgstat
functions that expose backend IDs at the SQL level. Those IDs are now
in fact 0-based ProcNumbers too, but the documentation still calls
them "backend ids". That term still seems appropriate to describe what
the numbers are, so I let it be.
One user-visible effect is that pg_temp_0 is now a valid temp schema
name, for backend with ProcNumber 0.
Reviewed-by: Andres Freund
Discussion: https://www.postgresql.org/message-id/8171f1aa-496f-46a6-afc3-c46fe7a9b407@iki.fi
Bhis commit introduces enhancements to the pg_stat_checkpointer view by adding
three new columns: restartpoints_timed, restartpoints_req, and
restartpoints_done. These additions aim to improve the visibility and
monitoring of restartpoint processes on replicas.
Previously, it was challenging to differentiate between successful and failed
restartpoint requests. This limitation arises because restartpoints on replicas
are dependent on checkpoint records from the primary, and cannot occur more
frequently than these checkpoints.
The new columns allow for clear distinction and tracking of restartpoint
requests, their triggers, and successful completions. This enhancement aids
database administrators and developers in better understanding and diagnosing
issues related to restartpoint behavior, particularly in scenarios where
restartpoint requests may fail.
System catalog is changed. Catversion is bumped.
Discussion: https://postgr.es/m/99b2ccd1-a77a-962a-0837-191cdf56c2b9%40inbox.ru
Author: Anton A. Melnikov
Reviewed-by: Kyotaro Horiguchi, Alexander Korotkov
Currently, pg_stat_reset_shared() cannot reset the counters in the view
pg_stat_slru even if it is a type of shared stats. This patch adds
support for a new value in pg_stat_reset_shared(), called "slru", able
to do that. Note that pg_stat_reset_shared(NULL) also resets SLRU
counters.
There may be a point in removing pg_stat_reset_slru() that was
introduced in 28cac71bd3 (v13~) as the new option overlaps with this
function, but we would lose the ability to reset individual SLRU
counters. This is left for future reconsideration.
Author: Atsushi Torikoshi
Discussion: https://postgr.es/m/e3c25d72e81378e7b64f3c52e0306fc9@oss.nttdata.com
Currently, pg_stat_reset_shared() can use an argument to specify the
target of statistics to reset, doing nothing for NULL as it is strict.
This patch adds to pg_stat_reset_shared() the possibility to reset all
the stats types already handled in this function rather than do nothing
if the argument value given is NULL or if nothing is specified
(proisstrict is switched to false). Like previously, SLRUs are not
included in what gets reset.
The idea to use NULL or no argument to control if all the shared stats
already covered by this function should be reset has been proposed by
Andres Freund.
Bump catalog version.
Author: Atsushi Torikoshi
Reviewed-by: Kyotaro Horiguchi, Michael Paquier, Bharath Rupireddy,
Matthias van de Meent
Discussion: https://postgr.es/m/4291a55137ddda77cf7cc5f46e846daf@oss.nttdata.com
Historically, the statistics of the checkpointer have been always part
of pg_stat_bgwriter. This commit removes a few columns from
pg_stat_bgwriter, and introduces pg_stat_checkpointer with equivalent,
renamed columns (plus a new one for the reset timestamp):
- checkpoints_timed -> num_timed
- checkpoints_req -> num_requested
- checkpoint_write_time -> write_time
- checkpoint_sync_time -> sync_time
- buffers_checkpoint -> buffers_written
The fields of PgStat_CheckpointerStats and its SQL functions are renamed
to match with the new field names, for consistency. Note that
background writer and checkpointer have been split into two different
processes in commits 806a2aee37 and bf405ba8e4. The pgstat
structures were already split, making this change straight-forward.
Bump catalog version.
Author: Bharath Rupireddy
Reviewed-by: Bertrand Drouvot, Andres Freund, Michael Paquier
Discussion: https://postgr.es/m/CALj2ACVxX2ii=66RypXRweZe2EsBRiPMj0aHfRfHUeXJcC7kHg@mail.gmail.com
This commit refactors find_tabstat_entry() so as transaction counters
for inserted, updated and deleted tuples are included in the result
returned. If a shared entry is found for a relation, its result is now
a copy of the PgStat_TableStatus entry retrieved from shared memory.
This idea has been proposed by Andres Freund.
While on it, the following SQL functions, used in system views, are
refactored with macros, in the same spirit as 83a1a1b566, reducing the
amount of code:
- pg_stat_get_xact_tuples_deleted()
- pg_stat_get_xact_tuples_inserted()
- pg_stat_get_xact_tuples_updated()
There is now only one caller of find_tabstat_entry() in the tree.
Author: Bertrand Drouvot
Discussion: https://postgr.es/m/b9e1f543-ee93-8168-d530-d961708ad9d3@gmail.com
Two attributes related to checkpointer statistics are removed in this
commit:
- buffers_backend, that counts the number of buffers written directly by
a backend.
- buffers_backend_fsync, that counts the number of times a backend had
to do fsync() by its own.
These are actually not checkpointer properties but backend properties.
Also, pg_stat_io provides a more accurate and equivalent report of these
numbers, by tracking all the I/O stats related to backends, including
writes and fsyncs, so storing them in pg_stat_checkpointer was
redundant.
Thanks also to Robert Haas and Amit Kapila for their input.
Bump catalog version.
Author: Bharath Rupireddy
Reviewed-by: Bertrand Drouvot, Andres Freund
Discussion: https://postgr.es/m/20230210004604.mcszbscsqs3bc5nx@awork3.anarazel.de
Unlike the other pg_stat_get_backend* functions,
pg_stat_get_backend_subxact() looks up the backend entry by using
its integer argument as a 1-based index in an internal array. The
other functions look for the entry with the matching session
backend ID. These numbers often match, but that isn't reliably
true.
This commit resolves this discrepancy by introducing
pgstat_get_local_beentry_by_backend_id() and using it in
pg_stat_get_backend_subxact(). We cannot use
pgstat_get_beentry_by_backend_id() because it returns a
PgBackendStatus, which lacks the locally computed additions
available in LocalPgBackendStatus that are required by
pg_stat_get_backend_subxact().
Author: Ian Barwick
Reviewed-by: Sami Imseih, Michael Paquier, Robert Haas
Discussion: https://postgr.es/m/CAB8KJ%3Dj-ACb3H4L9a_b3ZG3iCYDW5aEu3WsPAzkm2S7JzS1Few%40mail.gmail.com
Backpatch-through: 16
Presently, pgstat_fetch_stat_beentry() accepts a session's backend
ID as its argument, and pgstat_fetch_stat_local_beentry() accepts a
1-based index in an internal array as its argument. The former is
typically used wherever a user must provide a backend ID, and the
latter is usually used internally when looping over all entries in
the array. This difference was first introduced by d7e39d72ca.
Before that commit, both functions accepted a 1-based index to the
internal array.
This commit renames these two functions to make it clear whether
they use the backend ID or the 1-based index to look up the entry.
This is preparatory work for a follow-up change that will introduce
a function for looking up a LocalPgBackendStatus using a backend
ID.
Reviewed-by: Ian Barwick, Sami Imseih, Michael Paquier, Robert Haas
Discussion: https://postgr.es/m/CAB8KJ%3Dj-ACb3H4L9a_b3ZG3iCYDW5aEu3WsPAzkm2S7JzS1Few%40mail.gmail.com
Backpatch-through: 16
This commit fixes the function of $subject for shared relations. This
feature has been added by e042678. Unfortunately, this new behavior got
removed by 5891c7a when moving statistics to shared memory.
Reported-by: Mitsuru Hinata
Author: Masahiro Ikeda
Reviewed-by: Kyotaro Horiguchi, Masahiko Sawada
Discussion: https://postgr.es/m/7cc69f863d9b1bc677544e3accd0e4b4@oss.nttdata.com
Backpatch-through: 15
This adds the X509 attributes notBefore and notAfter to sslinfo
as well as pg_stat_ssl to allow verifying and identifying the
validity period of the current client certificate.
Author: Cary Huang <cary.huang@highgo.ca>
Discussion: https://postgr.es/m/182b8565486.10af1a86f158715.2387262617218380588@highgo.ca
Run pgindent and pgperltidy. It seems we're still some ways
away from all committers doing this automatically. Now that
we have a buildfarm animal that will whine about poorly-indented
code, we'll try to keep the tree more tidy.
Discussion: https://postgr.es/m/3156045.1687208823@sss.pgh.pa.us
28e626bde0 added the concept of IOOps but neglected to include writeback
operations. ac8d53dae5 added time spent doing these I/O operations. Without
counting writeback, checkpointer write time in the log often differed
substantially from that in pg_stat_io. To fix this, add IOOp IOOP_WRITEBACK
and track writeback in pg_stat_io.
Bumps catversion.
Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reported-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20230419172326.dhgyo4wrrhulovt6%40awork3.anarazel.de
a9c70b46 added the statistics view pg_stat_io which contained columns
"io_context" and "io_object". Given that the columns are in the
pg_stat_io view, the "io" prefix is somewhat redundant, so remove it.
The code variables referring to these fields are kept unchanged so as
they can keep their context about I/O.
Bump catalog version.
Author: Melanie Plageman
Reviewed-by: Kyotaro Horiguchi, Fabrízio de Royes Mello
Discussion: https://postgr.es/m/CAAKRu_aAQoJWrvT2BYYQvJChFKra_O-5ra3jhzKJZqWsTR1CPQ@mail.gmail.com
This reverts commit 3d03b24c3 (Revert Add support for Kerberos
credential delegation) which was committed on the grounds of concern
about portability, but on further review and discussion, it's clear that
we are better off explicitly requiring MIT Kerberos as that appears to
be the only GSSAPI library currently that's under proper maintenance
and ongoing development. The API used for storing credentials was added
to MIT Kerberos over a decade ago while for the other libraries which
appear to be mainly based on Heimdal, which exists explicitly to be a
re-implementation of MIT Kerberos, the API never made it to a released
version (even though it was added to the Heimdal git repo over 5 years
ago..).
This post-feature-freeze change was approved by the RMT.
Discussion: https://postgr.es/m/ZDDO6jaESKaBgej0%40tamriel.snowman.net
This reverts commit 3d4fa227bc.
Per discussion and buildfarm, this depends on APIs that seem to not
be available on at least one platform (NetBSD). Should be certainly
possible to rework to be optional on that platform if necessary but bit
late for that at this point.
Discussion: https://postgr.es/m/3286097.1680922218@sss.pgh.pa.us
During WAL replay on the standby, when a conflict with a logical slot is
identified, invalidate such slots. There are two sources of conflicts:
1) Using the information added in 6af1793954, logical slots are invalidated if
required rows are removed
2) wal_level on the primary server is reduced to below logical
Uses the infrastructure introduced in the prior commit. FIXME: add commit
reference.
Change InvalidatePossiblyObsoleteSlot() to use a recovery conflict to
interrupt use of a slot, if called in the startup process. The new recovery
conflict is added to pg_stat_database_conflicts, as confl_active_logicalslot.
See 6af1793954 for an overall design of logical decoding on a standby.
Bumps catversion for the addition of the pg_stat_database_conflicts column.
Bumps PGSTAT_FILE_FORMAT_ID for the same reason.
Author: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Author: Andres Freund <andres@anarazel.de>
Author: Amit Khandekar <amitdkhan.pg@gmail.com> (in an older version)
Reviewed-by: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Fabrízio de Royes Mello <fabriziomello@gmail.com>
Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/20230407075009.igg7be27ha2htkbt@awork3.anarazel.de
Support GSSAPI/Kerberos credentials being delegated to the server by a
client. With this, a user authenticating to PostgreSQL using Kerberos
(GSSAPI) credentials can choose to delegate their credentials to the
PostgreSQL server (which can choose to accept them, or not), allowing
the server to then use those delegated credentials to connect to
another service, such as with postgres_fdw or dblink or theoretically
any other service which is able to be authenticated using Kerberos.
Both postgres_fdw and dblink are changed to allow non-superuser
password-less connections but only when GSSAPI credentials have been
delegated to the server by the client and GSSAPI is used to
authenticate to the remote system.
Authors: Stephen Frost, Peifeng Qiu
Reviewed-By: David Christensen
Discussion: https://postgr.es/m/CO1PR05MB8023CC2CB575E0FAAD7DF4F8A8E29@CO1PR05MB8023.namprd05.prod.outlook.com
a9c70b46db and 8aaa04b32S added counting of IO operations to a new view,
pg_stat_io. Now, add IO timing for reads, writes, extends, and fsyncs to
pg_stat_io as well.
This combines the tracking for pgBufferUsage with the tracking for pg_stat_io
into a new function pgstat_count_io_op_time(). This should make it a bit
easier to avoid the somewhat costly instr_time conversion done for
pgBufferUsage.
Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: https://postgr.es/m/flat/CAAKRu_ay5iKmnbXZ3DsauViF3eMxu4m1oNnJXqV_HyqYeg55Ww%40mail.gmail.com
Among other things, this should make it easier to calculate a useful cache hit
ratio by excluding buffer reads via buffer access strategies. As buffer access
strategies reuse buffers (and thus evict the prior buffer contents), it is
normal to see reads on repeated scans of the same data.
Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CAAKRu_beMa9Hzih40%3DXPYqhDVz6tsgUGTrhZXRo%3Dunp%2Bszb%3DUA%40mail.gmail.com
Two new macros are added with their respective functions switched to
use them. These are for functions with millisecond stats, with and
without "xact" in their names (for the stats that can be tracked within
a transaction).
While on it, prefix the macro for float8 on database entries with "_MS",
as it does a us->ms conversion, based on a suggestion from Andres
Freund.
Author: Bertrand Drouvot
Discussion: https://postgr.es/m/6e2efb4f-6fd0-807e-f6bf-94207db8183a@gmail.com
This commit renames the members of a few pgstat structures related to
functions and relations, by respectively removing their prefix "f_" and
"t_". The statistics for functions and relations and handled in their
own file, and pgstatfuncs.c associates each field in a structure
variable named based on the object type handled, so no information is
lost with this rename.
This will help with some of the refactoring aimed for pgstatfuncs.c, as
this makes more consistent the field names with the SQL functions
retrieving them.
Author: Bertrand Drouvot
Reviewed-by: Michael Paquier, Melanie Plageman
Discussion: https://postgr.es/m/9142f62a-a422-145c-bde0-b5bc498a4ada@gmail.com
Add pgstat counter to track row updates that result in the successor
version going to a new heap page, leaving behind an original version
whose t_ctid points to the new version. The current count is shown by
the n_tup_newpage_upd column of each of the pg_stat_*_tables views.
The new n_tup_newpage_upd column complements the existing n_tup_hot_upd
and n_tup_upd columns. Tables that have high n_tup_newpage_upd values
(relative to n_tup_upd) are good candidates for tuning heap fillfactor.
Corey Huinker, with small tweaks by me.
Author: Corey Huinker <corey.huinker@gmail.com>
Reviewed-By: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CADkLM=ded21M9iZ36hHm-vj2rE2d=zcKpUQMds__Xm2pxLfHKA@mail.gmail.com
This structure included only PgStat_FunctionCounts, and removing it
facilitates some upcoming refactoring for pgstatfuncs.c to use more
macros rather that mostly-duplicated functions.
Author: Bertrand Drouvot
Reviewed-by: Nathan Bossart
Discussion: https://postgr.es/m/11d531fe-52fc-c6ea-7e8e-62f1b6ec626e@gmail.com
Some clang versions whine about comparing an enum variable to
a value outside the range of the enum, on the grounds that the
result must be constant. In the cases we fix here, the loops
will terminate only if the enum variable can in fact hold a
value one beyond its declared range. While that's very likely
to always be true for these enum types, it still seems like a
poor coding practice to assume it; so use "int" loop variables
instead to silence the warnings. (This matches what we've done
in other places, for example loops over the range of ForkNumber.)
While at it, let's drop the XXX_FIRST macros for these enums and just
write zeroes for the loop start values. The apparent flexibility
seems rather illusory given that iterating up to one-less-than-
the-number-of-values is only correct for a zero-based range.
Melanie Plageman
Discussion: https://postgr.es/m/20520.1677435600@sss.pgh.pa.us
Builds on 28e626bde0 and f30d62c2fc. See the former for motivation.
Rows of the view show IO operations for a particular backend type, IO target
object, IO context combination (e.g. a client backend's operations on
permanent relations in shared buffers) and each column in the view is the
total number of IO Operations done (e.g. writes). So a cell in the view would
be, for example, the number of blocks of relation data written from shared
buffers by client backends since the last stats reset.
In anticipation of tracking WAL IO and non-block-oriented IO (such as
temporary file IO), the "op_bytes" column specifies the unit of the "reads",
"writes", and "extends" columns for a given row.
Rows for combinations of IO operation, backend type, target object and context
that never occur, are ommitted entirely. For example, checkpointer will never
operate on temporary relations.
Similarly, if an IO operation never occurs for such a combination, the IO
operation's cell will be null, to distinguish from 0 observed IO
operations. For example, bgwriter should not perform reads.
Note that some of the cells in the view are redundant with fields in
pg_stat_bgwriter (e.g. buffers_backend). For now, these have been kept for
backwards compatibility.
Bumps catversion.
Author: Melanie Plageman <melanieplageman@gmail.com>
Author: Samay Sharma <smilingsamay@gmail.com>
Reviewed-by: Maciek Sakrejda <m.sakrejda@gmail.com>
Reviewed-by: Lukas Fittl <lukas@fittl.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/20200124195226.lth52iydq2n2uilq@alap3.anarazel.de
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
Add leader_pid to pg_stat_subscription. leader_pid is the process ID of
the leader apply worker if this process is a parallel apply worker. If
this field is NULL, it indicates that the process is a leader apply
worker or a synchronization worker. The new column makes it easier to
distinguish parallel apply workers from other kinds of workers and helps
to identify the leader for the parallel workers corresponding to a
particular subscription.
Additionally, update the leader_pid column in pg_stat_activity as well to
display the PID of the leader apply worker for parallel apply workers.
Author: Hou Zhijie
Reviewed-by: Peter Smith, Sawada Masahiko, Amit Kapila, Shveta Mallik
Discussion: https://postgr.es/m/CAA4eK1+wyN6zpaHUkCLorEWNx75MG0xhMwcFhvjqm2KURZEAGw@mail.gmail.com
A new function pg_stat_get_backend_subxact() can be used to get
information about the number of subtransactions in the cache of
a particular backend and whether that cache has overflowed. This
can be useful for tracking down performance problems that can
result from overflowed snapshots.
Dilip Kumar, reviewed by Zhihong Yu, Nikolay Samokhvalov,
Justin Pryzby, Nathan Bossart, Ashutosh Sharma, Julien
Rouhaud. Additional design comments from Andres Freund,
Tom Lane, Bruce Momjian, and David G. Johnston.
Discussion: http://postgr.es/m/CAFiTN-ut0uwkRJDQJeDPXpVyTWD46m3gt3JDToE02hTfONEN=Q@mail.gmail.com
Michael Paquier