Currently tab completion for ALTER USER RESET shows a list of all
configuration parameters that may be set on a role, irrespectively of
which parameters are actually set. This patch improves tab completion to
offer only parameters that are set.
Author: Robins Tharakan
Reviewed-By: Tomas Vondra
Discussion: https://postgr.es/m/CAEP4nAzqiT6VbVC5r3nq5byLTnPzjniVGzEMpYcnAHQyNzEuaw%40mail.gmail.com
Currently tab completion for ALTER DATABASE RESET shows a list of all
configuration parameters that may be set on a database, irrespectively
of which parameters are actually set. This patch improves tab completion
to offer only parameters that are set.
Author: Robins Tharakan
Reviewed-By: Tomas Vondra
Discussion: https://postgr.es/m/CAEP4nAzqiT6VbVC5r3nq5byLTnPzjniVGzEMpYcnAHQyNzEuaw%40mail.gmail.com
The Self-Join Elimination (SJE) feature removes an inner join of a plain
table to itself in the query tree if it is proven that the join can be
replaced with a scan without impacting the query result. Self-join and
inner relation get replaced with the outer in query, equivalence classes,
and planner info structures. Also, the inner restrictlist moves to the
outer one with the removal of duplicated clauses. Thus, this optimization
reduces the length of the range table list (this especially makes sense for
partitioned relations), reduces the number of restriction clauses and,
in turn, selectivity estimations, and potentially improves total planner
prediction for the query.
This feature is dedicated to avoiding redundancy, which can appear after
pull-up transformations or the creation of an EquivalenceClass-derived clause
like the below.
SELECT * FROM t1 WHERE x IN (SELECT t3.x FROM t1 t3);
SELECT * FROM t1 WHERE EXISTS (SELECT t3.x FROM t1 t3 WHERE t3.x = t1.x);
SELECT * FROM t1,t2, t1 t3 WHERE t1.x = t2.x AND t2.x = t3.x;
In the future, we could also reduce redundancy caused by subquery pull-up
after unnecessary outer join removal in cases like the one below.
SELECT * FROM t1 WHERE x IN
(SELECT t3.x FROM t1 t3 LEFT JOIN t2 ON t2.x = t1.x);
Also, it can drastically help to join partitioned tables, removing entries
even before their expansion.
The SJE proof is based on innerrel_is_unique() machinery.
We can remove a self-join when for each outer row:
1. At most, one inner row matches the join clause;
2. Each matched inner row must be (physically) the same as the outer one;
3. Inner and outer rows have the same row mark.
In this patch, we use the next approach to identify a self-join:
1. Collect all merge-joinable join quals which look like a.x = b.x;
2. Add to the list above the baseretrictinfo of the inner table;
3. Check innerrel_is_unique() for the qual list. If it returns false, skip
this pair of joining tables;
4. Check uniqueness, proved by the baserestrictinfo clauses. To prove the
possibility of self-join elimination, the inner and outer clauses must
match exactly.
The relation replacement procedure is not trivial and is partly combined
with the one used to remove useless left joins. Tests covering this feature
were added to join.sql. Some of the existing regression tests changed due
to self-join removal logic.
Discussion: https://postgr.es/m/flat/64486b0b-0404-e39e-322d-0801154901f3%40postgrespro.ru
Author: Andrey Lepikhov <a.lepikhov@postgrespro.ru>
Author: Alexander Kuzmenkov <a.kuzmenkov@postgrespro.ru>
Co-authored-by: Alexander Korotkov <aekorotkov@gmail.com>
Co-authored-by: Alena Rybakina <lena.ribackina@yandex.ru>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Simon Riggs <simon@2ndquadrant.com>
Reviewed-by: Jonathan S. Katz <jkatz@postgresql.org>
Reviewed-by: David Rowley <david.rowley@2ndquadrant.com>
Reviewed-by: Thomas Munro <thomas.munro@enterprisedb.com>
Reviewed-by: Konstantin Knizhnik <k.knizhnik@postgrespro.ru>
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Hywel Carver <hywel@skillerwhale.com>
Reviewed-by: Laurenz Albe <laurenz.albe@cybertec.at>
Reviewed-by: Ronan Dunklau <ronan.dunklau@aiven.io>
Reviewed-by: vignesh C <vignesh21@gmail.com>
Reviewed-by: Zhihong Yu <zyu@yugabyte.com>
Reviewed-by: Greg Stark <stark@mit.edu>
Reviewed-by: Jaime Casanova <jcasanov@systemguards.com.ec>
Reviewed-by: Michał Kłeczek <michal@kleczek.org>
Reviewed-by: Alena Rybakina <lena.ribackina@yandex.ru>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
ExecInitModifyTable() forgot to trim MERGE-related lists to exclude
entries for result relations pruned during initial pruning, so fix
that.
While at it, make the function's use of the pruned resultRelations
list, rather than ModifyTable.resultRelations, more consistent.
Reported-by: Alexander Lakhin <exclusion@gmail.com> (via sqlsmith)
Reviewed-by: Junwang Zhao <zhjwpku@gmail.com>
Discussion: https://postgr.es/m/e72c94d9-e5f9-4753-9bc1-69d72bd54b8a@gmail.com
This commit adds the information about the number of times WAL buffers
have been full to the logs generated by VACUUM/ANALYZE (VERBOSE) and in
the logs generated by autovacuum, complementing the existing information
stored by WalUsage.
This is the last part of the backend code where the value of
wal_buffers_full can be reported, similarly to all the other fields of
WalUsage. 320545bfcfee and ce5bcc4a9f26 have done the same for EXPLAIN
and pgss.
Author: Bertrand Drouvot
Reviewed-by: Ilia Evdokimov
Discussion: https://postgr.es/m/Z6SOha5YFFgvpwQY@ip-10-97-1-34.eu-west-3.compute.internal
This is similar to ce5bcc4a9f26, relying on the addition of
wal_buffers_full to WalUsage. This time, the information is added to
the output generated by EXPLAIN (WAL).
Author: Bertrand Drouvot
Reviewed-by: Ilia Evdokimov
Discussion: https://postgr.es/m/Z6SOha5YFFgvpwQY@ip-10-97-1-34.eu-west-3.compute.internal
wal_buffers_full has been introduced in pg_stat_wal in 8d9a935965f, as
some information providing metrics for the tuning of the GUC
wal_buffers. WalUsage has been introduced before that in df3b181499.
Moving this field is proving to be beneficial for several reasons:
- This information can now be made available in more layers, providing
more granularity than just pg_stat_wal, on a per-query basis: EXPLAIN,
pgss and VACUUM/ANALYZE logs.
- A patch is under discussion to provide statistics for WAL at backend
level, and this move simplifies a bit the handling of pending
statistics. The remaining data in PgStat_PendingWalStats now relates to
write/sync counters and times, with equivalents present in pg_stat_io,
that backend statistics are able to already track. So this should cut
all the dependencies between PgStat_PendingWalStats and WAL stats at
backend level.
As of this change, wal_buffers_full only shows in pg_stat_wal.
Author: Bertrand Drouvot
Reviewed-by: Ilia Evdokimov
Discussion: https://postgr.es/m/Z6SOha5YFFgvpwQY@ip-10-97-1-34.eu-west-3.compute.internal
Allow multiple backends to initialize WAL buffers concurrently. This way
`MemSet((char *) NewPage, 0, XLOG_BLCKSZ);` can run in parallel without
taking a single LWLock in exclusive mode.
The new algorithm works as follows:
* reserve a page for initialization using XLogCtl->InitializeReserved,
* ensure the page is written out,
* once the page is initialized, try to advance XLogCtl->InitializedUpTo and
signal to waiters using XLogCtl->InitializedUpToCondVar condition
variable,
* repeat previous steps until we reserve initialization up to the target
WAL position,
* wait until concurrent initialization finishes using a
XLogCtl->InitializedUpToCondVar.
Now, multiple backends can, in parallel, concurrently reserve pages,
initialize them, and advance XLogCtl->InitializedUpTo to point to the latest
initialized page.
Author: Yura Sokolov <y.sokolov@postgrespro.ru>
Co-authored-by: Alexander Korotkov <aekorotkov@gmail.com>
Reviewed-by: Pavel Borisov <pashkin.elfe@gmail.com>
In set_append_rel_size(), we currently set rel->tuples to rel->rows
for an appendrel. Generally, rel->tuples is the raw number of tuples
in the relation and rel->rows is the estimated number of tuples after
the relation's restriction clauses have been applied. Although an
appendrel itself doesn't directly enforce any quals today, its child
relations may. Therefore, setting rel->tuples equal to rel->rows for
an appendrel isn't always appropriate.
Doing so can lead to issues in cost estimates in some cases. For
instance, when estimating the number of distinct values from an
appendrel, we would not be able to adjust the estimate based on the
restriction selectivity.
This patch addresses this by setting an appendrel's tuples to the
total number of tuples accumulated from each live child, which better
aligns with reality.
This is arguably a bug, but nobody has complained about that until
now, so no back-patch.
Author: Richard Guo <guofenglinux@gmail.com>
Reviewed-by: Tender Wang <tndrwang@gmail.com>
Reviewed-by: Alena Rybakina <a.rybakina@postgrespro.ru>
Discussion: https://postgr.es/m/CAMbWs4_TG_+kVn6fjG-5GYzzukrNK57=g9eUo4gsrUG26OFawg@mail.gmail.com
Coverity complained that we weren't doing that, and it's right.
This fix just makes fmtIdEnc() honor the general convention that OOM
causes a PQExpBuffer to become marked "broken", without any immediate
error. In the pretty-unlikely case that we actually did hit OOM here,
the end result would be to return an empty string to the caller,
probably resulting in invalid SQL syntax in an issued command (if
nothing else went wrong, which is even more unlikely). It's tempting
to throw an "out of memory" error if the buffer becomes broken, but
there's not a lot of point in doing that only here and not in hundreds
of other PQExpBuffer-using places in pg_dump and similar callers.
The whole issue could do with some non-time-crunched redesign, perhaps.
This is a followup to the fixes for CVE-2025-1094, and should be
included if cherry-picking those fixes.
Instead of dropping the trailing byte(s) of an invalid or incomplete
multibyte character, replace only the first byte with a known-invalid
sequence, and process the rest normally. This seems less likely to
confuse incautious callers than the behavior adopted in 5dc1e42b4.
While we're at it, adjust PQescapeStringInternal to produce at most
one bleat about invalid multibyte characters per string. This
matches the behavior of PQescapeInternal, and avoids the risk of
producing tons of repetitive junk if a long string is simply given
in the wrong encoding.
This is a followup to the fixes for CVE-2025-1094, and should be
included if cherry-picking those fixes.
Author: Andres Freund <andres@anarazel.de>
Co-authored-by: Tom Lane <tgl@sss.pgh.pa.us>
Reported-by: Jeff Davis <pgsql@j-davis.com>
Discussion: https://postgr.es/m/20250215012712.45@rfd.leadboat.com
Backpatch-through: 13
By calling wipe_mem() on per-buffer data memory that has been released,
we are also telling Valgrind that the memory is "noaccess". We need to
set it to "undefined" before giving it to the registered callback to
fill in, when a slot is reused.
As discovered by build farm animal skink when the VACUUM streamification
patches landed (the first users of per-buffer data).
Pushing to master only for now, to clear the error on skink. It's also
possible that external code might discover the per-buffer data feature
in v17, and reasonable to expect Valgrind not to produce spurious
memcheck reports, but the back-patch is deferred until after the
imminent minor release is out of the way.
Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Tested-by: Melanie Plageman <melanieplageman@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKG%2Bg6aXpi2FEHqeLOzE%2BxYw%3DOV%2B-N5jhOEnnV%2BF0USM9xA%40mail.gmail.com
In 5dc1e42b4fa I fixed bugs in various escape functions, unfortunately as part
of that I introduced a new bug in PQescapeLiteral()/PQescapeIdentifier(). The
bug is that I made PQescapeInternal() just use strlen(), rather than taking
the specified input length into account.
That's bad, because it can lead to including input that wasn't intended to be
included (in case len is shorter than null termination of the string) and
because it can lead to reading invalid memory if the input string is not null
terminated.
Expand test_escape to this kind of bug:
a) for escape functions with length support, append data that should not be
escaped and check that it is not
b) add valgrind requests to detect access of bytes that should not be touched
Author: Tom Lane <tgl@sss.pgh.pa.us>
Author: Andres Freund <andres@anarazel.de
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Noah Misch <noah@leadboat.com>
Discussion: https://postgr.es/m/Z64jD3u46gObCo1p@pryzbyj2023
Backpatch: 13
Commit bb8dff9995 added this information to the
pg_stat_progress_vacuum and pg_stat_progress_analyze system views.
This commit adds the same information to the output of VACUUM and
ANALYZE with the VERBOSE option and to the autovacuum logs.
Suggested-by: Masahiro Ikeda <ikedamsh@oss.nttdata.com>
Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: https://postgr.es/m/ZmaXmWDL829fzAVX%40ip-10-97-1-34.eu-west-3.compute.internal
Make vacuum's third phase (its second pass over the heap), which reaps
dead items collected in the first phase and marks them as reusable, use
the read stream API. This commit adds a new read stream callback,
vacuum_reap_lp_read_stream_next(), that looks ahead in the TidStore and
returns the next block number to read for vacuum.
Author: Melanie Plageman <melanieplageman@gmail.com>
Co-authored-by: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKGKN3oy0bN_3yv8hd78a4%2BM1tJC9z7mD8%2Bf%2ByA%2BGeoFUwQ%40mail.gmail.com
Make vacuum's first phase, which prunes and freezes tuples and records
dead TIDs, use the read stream API by by converting
heap_vac_scan_next_block() to a read stream callback.
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/CAAKRu_aLwANZpxHc0tC-6OT0OQT4TftDGkKAO5yigMUOv_Tcsw%40mail.gmail.com
The read stream API only allows one piece of extra per block state to be
passed back to the API user (per_buffer_data). lazy_scan_heap() needs
two pieces of per-buffer data: whether or not the block was all-visible
in the visibility map and whether or not it was eagerly scanned.
Convert these two pieces of information to flags so that they can be
populated by heap_vac_scan_next_block() and returned to
lazy_scan_heap(). A future commit will turn heap_vac_scan_next_block()
into the read stream callback for heap phase I vacuuming.
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/CAAKRu_bmx33jTqATP5GKNFYwAg02a9dDtk4U_ciEjgBHZSVkOQ%40mail.gmail.com
Many GUCs accept special values like -1 or an empty string to
disable the feature, use a system default, etc. While the
documentation consistently lists these special values, the GUC
descriptions do not. Many such descriptions fail to mention the
special values, and those that do vary in phrasing and placement.
This commit aims to bring some consistency to this area by applying
the following rules:
* Special values should be listed at the end of the long
description.
* Descriptions should use numerals (e.g., "0") instead of words
(e.g., "zero").
* Special value mentions should be concise and direct (e.g., "0
disables the timeout.", "An empty string means use the operating
system setting.").
* Multiple special values should be listed in ascending order.
Of course, there are exceptions, such as
max_pred_locks_per_relation and search_path, whose special values
are too complex to include. And there are cases like
listen_addresses, where the meaning of an empty string is arguably
too obvious to include. In those cases, I've refrained from adding
special value information to the GUC description.
Reviewed-by: Peter Smith <smithpb2250@gmail.com>
Reviewed-by: "David G. Johnston" <david.g.johnston@gmail.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/Z6aIy4aywxUZHAo6%40nathan
Commit 27cc7cd2bc8a accidentally placed the assertion ensuring
that the pointer isn't NULL after it had already been accessed.
Fix by moving the pointer dereferencing to after the assertion.
Backpatch to all supported branches.
Author: Dmitry Koval <d.koval@postgrespro.ru>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/1618848d-cdc7-414b-9c03-08cf4bef4408@postgrespro.ru
Backpatch-through: 13
Commit 755a4c10d19d prevented StartReadBuffers() from crossing md.c
segment boundaries in one operation, but a comment about that
possibility remained.
When an UPDATE trigger referencing a new table and a DELETE trigger
referencing an old table are both present, MakeTransitionCaptureState()
returns an inconsistent result for UPDATE commands in its set of flags
and tuplestores holding the TransitionCaptureState for transition
tables.
As proved by the test added here, this issue causes a crash in v14 and
earlier versions (down to 11, actually, older versions do not support
triggers on partitioned tables) during cross-partition updates on a
partitioned table. v15 and newer versions are safe thanks to
7103ebb7aae8.
This commit fixes the function so that it returns a consistent state
by using portions of the changes made in commit 7103ebb7aae8 for v13 and
v14. v15 and newer versions are slightly tweaked to match with the
older versions, mainly for consistency across branches.
Author: Kyotaro Horiguchi
Discussion: https://postgr.es/m/20250207.150238.968446820828052276.horikyota.ntt@gmail.com
Backpatch-through: 13
RBTXN_PREPARE flag and rbtxn_prepared macro could be misinterpreted as
either indicating the transaction type (e.g. a prepared transaction or
a normal transaction) or its currentstate (e.g. skipped or its prepare
message is sent), especially after commit 072ee847ad4 introduced the
RBTXN_SENT_PREPARE flag and the rbtxn_sent_prepare macro.
The RBTXN_PREPARE flag (and its corresponding macro) have been renamed
to RBTXN_IS_PREPARE to explicitly indicate the transaction
type. Therefore, this commit also adds the RBTXN_IS_PREPARE flag to
the transaction that is a prepared transaction and has been skipped,
which previously had only the RBTXN_SKIPPED_PREPARE flag.
Reviewed-by: Amit Kapila, Peter Smith
Discussion: https://postgr.es/m/CAA4eK1KgNmBsG%3D155E7QQ6TX9RoWnM4z5Z20SvsbwxSe_QXYsg%40mail.gmail.com
Previously, transaction aborts were detected concurrently only during
system catalog scans while replaying a transaction in streaming mode.
This commit adds an additional CLOG lookup to check the transaction
status, allowing the logical decoding to skip changes also when it
doesn't touch system catalogs, if the transaction is already
aborted. This optimization enhances logical decoding performance,
especially for large transactions that have already been rolled back,
as it avoids unnecessary disk or network I/O.
To avoid potential slowdowns caused by frequent CLOG lookups for small
transactions (most of which commit), the CLOG lookup is performed only
for large transactions before eviction. The performance benchmark
results showed there is not noticeable performance regression due to
CLOG lookups.
Reviewed-by: Amit Kapila, Peter Smith, Vignesh C, Ajin Cherian
Reviewed-by: Dilip Kumar, Andres Freund
Discussion: https://postgr.es/m/CAD21AoDht9Pz_DFv_R2LqBTBbO4eGrpa9Vojmt5z5sEx3XwD7A@mail.gmail.com
Currently, the save_nestlevel variable in fmgr_security_definer()
is marked volatile. While this may have been necessary when it was
used in a PG_CATCH section (as explained in the comment for PG_TRY
in elog.h), it appears to have been unnecessary since commit
82a47982f3, which removed its use in a PG_CATCH section.
Author: Julien Rouhaud <rjuju123@gmail.com>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: https://postgr.es/m/Z6xbAgXKY2L-3d5Q%40jrouhaud
Coverity complained about possible double free of HandleCopyStream's
"copybuf". AFAICS it's mistaken, but it is easy to see why it's
confused, because management of that buffer is impossibly confusing.
It's unreasonable that HandleEndOfCopyStream frees the buffer in some
cases but not others, updates the caller's state for that in no case,
and has not a single comment about how complicated that makes things.
Let's put all the responsibility for freeing copybuf in the actual
owner of that variable, HandleCopyStream. This results in one more
PQfreemem call than before, but the logic is far easier to follow,
both for humans and machines.
Since this isn't (quite) actually broken, no back-patch.
Coverity reported the two oversights in getPublicationTables.
Valgrind found the one in determineNotNullFlags.
The mistakes in getPublicationTables seem too minor to be worth
back-patching. determineNotNullFlags could be run enough times
to matter, but that code is new in v18. So, no back-patch.
The phase of the test waiting for a restartpoint to complete was not
working as intended, due to a log_contains() call incorrectly
written.
The problem reported by the author could be simply reproduced by
removing the injection_points_wakeup() call: the test succeeds rather
than waiting for the restartpoint completion. In most cases, the
restartpoint completion is fast enough that the test offered the wanted
coverage. On slow machines, it could have become unreliable.
Oversight in 6782709df81f.
Author: Nitin Jadhav
Discussion: https://postgr.es/m/CAMm1aWa_6u+o52r7h7G6pX-oWD0Qraf0ee17Ma50qxGS0B_Rzg@mail.gmail.com
Backpatch-through: 17
The correct function documented to free the memory allocated for the
result returned by PQescapeIdentifier() and PQescapeLiteral() is
PQfreemem(). pg_createsubscriber.c relied on pg_free() instead, which
is not incorrect as both do a free() internally, but inconsistent with
the documentation.
While on it, this commit fixes a small memory leak introduced by
4867f8a555ce, as the code of pg_createsubscriber makes this effort.
Author: Ranier Vilela
Reviewed-by: Euler Taveira
Discussion: https://postgr.es/m/CAEudQAp=AW5dJXrGLbC_aZg_9nOo=42W7uLDRONFQE-gcgnkgQ@mail.gmail.com
Backpatch-through: 17
Remove some (char *) casts related to uses of the pg_checksum_page()
function. These casts are useless, because everything involved
already has the right type. Moreover, these casts actually silently
discarded a const qualifier. The declaration of a higher-level
function needs to be adjusted to fix that.
Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Discussion: https://www.postgresql.org/message-id/flat/fd1fcedb-3492-4fc8-9e3e-74b97f2db6c7%40eisentraut.org
Remove (char *) casts around memory functions such as memcmp(),
memcpy(), or memset() where the cast is useless. Since these
functions don't take char * arguments anyway, these casts are at best
complicated casts to (void *), about which see commit 7f798aca1d5.
Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Discussion: https://www.postgresql.org/message-id/flat/fd1fcedb-3492-4fc8-9e3e-74b97f2db6c7%40eisentraut.org
Remove (char *) casts around string functions where the arguments or
result already have the right type and the cast is useless (or worse,
potentially casts away a qualifier, but this doesn't appear to be the
case here).
Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Discussion: https://www.postgresql.org/message-id/flat/fd1fcedb-3492-4fc8-9e3e-74b97f2db6c7%40eisentraut.org
This commit adds the amount of time spent sleeping due to
cost-based delay to the pg_stat_progress_vacuum and
pg_stat_progress_analyze system views. A new configuration
parameter named track_cost_delay_timing, which is off by default,
controls whether this information is gathered. For vacuum, the
reported value includes the sleep time of any associated parallel
workers. However, parallel workers only report their sleep time
once per second to avoid overloading the leader process.
Bumps catversion.
Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Co-authored-by: Nathan Bossart <nathandbossart@gmail.com>
Reviewed-by: Sami Imseih <samimseih@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Masahiro Ikeda <ikedamsh@oss.nttdata.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Sergei Kornilov <sk@zsrv.org>
Discussion: https://postgr.es/m/ZmaXmWDL829fzAVX%40ip-10-97-1-34.eu-west-3.compute.internal
This function is used in both vacuum and analyze code paths, and a
follow-up commit will require distinguishing between the two. This
commit forces callers to specify whether they are in a vacuum or
analyze path, but it does not use that information for anything
yet.
Author: Nathan Bossart <nathandbossart@gmail.com>
Co-authored-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: https://postgr.es/m/ZmaXmWDL829fzAVX%40ip-10-97-1-34.eu-west-3.compute.internal
pgbench client-side data generation uses COPY FREEZE to load data for most
tables. COPY FREEZE isn't supported for partitioned tables and since pgbench
only supports partitioning pgbench_accounts, pgbench used a hard-coded check to
skip COPY FREEZE and use plain COPY for a partitioned pgbench_accounts.
If the user has manually partitioned one of the other pgbench tables, this
causes client-side data generation to error out with:
ERROR: cannot perform COPY FREEZE on a partitioned table
Fix this by limiting COPY FREEZE to ordinary tables (RELKIND_RELATION).
Author: Sergey Tatarintsev <s.tatarintsev@postgrespro.ru>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/flat/97f55fca-8a7b-4da8-b413-7d1c57010676%40postgrespro.ru
Aggressive vacuums must scan every unfrozen tuple in order to advance
the relfrozenxid/relminmxid. Because data is often vacuumed before it is
old enough to require freezing, relations may build up a large backlog
of pages that are set all-visible but not all-frozen in the visibility
map. When an aggressive vacuum is triggered, all of these pages must be
scanned. These pages have often been evicted from shared buffers and
even from the kernel buffer cache. Thus, aggressive vacuums often incur
large amounts of extra I/O at the expense of foreground workloads.
To amortize the cost of aggressive vacuums, eagerly scan some
all-visible but not all-frozen pages during normal vacuums.
All-visible pages that are eagerly scanned and set all-frozen in the
visibility map are counted as successful eager freezes and those not
frozen are counted as failed eager freezes.
If too many eager scans fail in a row, eager scanning is temporarily
suspended until a later portion of the relation. The number of failures
tolerated is configurable globally and per table.
To effectively amortize aggressive vacuums, we cap the number of
successes as well. Capping eager freeze successes also limits the amount
of potentially wasted work if these pages are modified again before the
next aggressive vacuum. Once we reach the maximum number of blocks
successfully eager frozen, eager scanning is disabled for the remainder
of the vacuum of the relation.
Original design idea from Robert Haas, with enhancements from
Andres Freund, Tomas Vondra, and me
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Robert Treat <rob@xzilla.net>
Reviewed-by: Bilal Yavuz <byavuz81@gmail.com>
Discussion: https://postgr.es/m/flat/CAAKRu_ZF_KCzZuOrPrOqjGVe8iRVWEAJSpzMgRQs%3D5-v84cXUg%40mail.gmail.com
"I/O" seems more descriptive than "Asynchronous Behavior", given that some of
the GUCs in the section don't relate to anything asynchronous.
Most other abbreviations in the config sections are un-abbreviated, but
"Input/Output" seems less likely to be helpful than just IO or I/O.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/x3tlw2jk5gm3r3mv47hwrshffyw7halpczkfbk3peksxds7bvc@lguk43z3bsyq
Commit 1dc5ebc90 allowed PL/pgSQL to perform in-place updates
of expanded-object variables that are being updated with
assignments like "x := f(x, ...)". However this was allowed
only for a hard-wired list of functions f(), since we need to
be sure that f() will not modify the variable if it fails.
It was always envisioned that we should make that extensible,
but at the time we didn't have a good way to do so. Since
then we've invented the idea of "support functions" to allow
attaching specialized optimization knowledge to functions,
and that is a perfect mechanism for doing this.
Hence, adjust PL/pgSQL to use a support function request instead
of hard-wired logic to decide if in-place update is safe.
Preserve the previous optimizations by creating support functions
for the three functions that were previously hard-wired.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Reviewed-by: Pavel Borisov <pashkin.elfe@gmail.com>
Discussion: https://postgr.es/m/CACxu=vJaKFNsYxooSnW1wEgsAO5u_v1XYBacfVJ14wgJV_PYeg@mail.gmail.com
If a read/write expanded variable is declared locally to the
assignment statement that is updating it, and it is referenced
exactly once in the assignment RHS, then we can optimize the
operation as a direct update of the expanded value, whether
or not the function(s) operating on it can be trusted not to
modify the value before throwing an error. This works because
if an error does get thrown, we no longer care what value the
variable has.
In cases where that doesn't work, fall back to the previous
rule that checks for safety of the top-level function.
In any case, postpone determination of whether these optimizations
are feasible until we are executing a Param referencing the target
variable and that variable holds a R/W expanded object. While the
previous incarnation of exec_check_rw_parameter was pretty cheap,
this is a bit less so, and our plan to invoke support functions
will make it even less so. So avoiding the check for variables
where it couldn't be useful should be a win.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Reviewed-by: Pavel Borisov <pashkin.elfe@gmail.com>
Discussion: https://postgr.es/m/CACxu=vJaKFNsYxooSnW1wEgsAO5u_v1XYBacfVJ14wgJV_PYeg@mail.gmail.com
Mark whether the target of a potentially optimizable assignment
is "local", in the sense of being declared inside any exception
block that could trap an error thrown from the assignment.
(This implies that we needn't preserve the variable's value
in case of an error. This patch doesn't do anything with the
knowledge, but the next one will.)
Normally, this requires a post-parsing scan of the function's
parse tree, since we don't know while parsing a BEGIN ...
construct whether we will find EXCEPTION at its end. However,
if there are no BEGIN ... EXCEPTION blocks in the function at
all, then all assignments are local, even those to variables
representing function arguments. We optimize that common case
by initializing the target_is_local flags to "true", and fixing
them up with a post-scan only if we found EXCEPTION.
Note that variables' default-value expressions are never interesting
for expanded-variable optimization, since they couldn't contain a
reference to the target variable anyway. But the code is set up
to compute their target_param and target_is_local correctly anyway,
for consistency and in case someone thinks of a use for that data.
I added a bit of plpgsql_dumptree support to help verify that this
code sets the flags as expected. I also added a plpgsql_dumptree
call in plpgsql_compile_inline. It was at best an oversight that
"#option dump" didn't work in a DO block; now it does.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Reviewed-by: Pavel Borisov <pashkin.elfe@gmail.com>
Discussion: https://postgr.es/m/CACxu=vJaKFNsYxooSnW1wEgsAO5u_v1XYBacfVJ14wgJV_PYeg@mail.gmail.com
This short and boring patch simply moves the responsibility for
initializing PLpgSQL_expr.target_param into plpgsql parsing,
rather than doing it at first execution of the expr as before.
This doesn't save anything in terms of runtime, since the work was
trivial and done only once per expr anyway. But it makes the info
available during parsing, which will be useful for the next step.
Likewise set PLpgSQL_expr.func during parsing. According to the
comments, this was once impossible; but it's certainly possible
since we invented the plpgsql_curr_compile variable. Again, this
saves little runtime, but it seems far cleaner conceptually.
While at it, I reordered stuff in struct PLpgSQL_expr to make it
clearer which fields are filled when, and merged some duplicative
code in pl_gram.y.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Reviewed-by: Pavel Borisov <pashkin.elfe@gmail.com>
Discussion: https://postgr.es/m/CACxu=vJaKFNsYxooSnW1wEgsAO5u_v1XYBacfVJ14wgJV_PYeg@mail.gmail.com
We haven't done this up to now because there was only one use-case,
namely plpgsql_free_function_memory's search for expressions to clean
up. However an upcoming patch has another need for walking plpgsql
functions' statement trees, so let's create sharable tree-walker
infrastructure in the same style as expression_tree_walker().
This patch actually makes the code shorter, although that's
mainly down to having used a more compact coding style. (I didn't
write a separate subroutine for each statement type, and I made
use of some newer notations like foreach_ptr.)
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Reviewed-by: Pavel Borisov <pashkin.elfe@gmail.com>
Discussion: https://postgr.es/m/CACxu=vJaKFNsYxooSnW1wEgsAO5u_v1XYBacfVJ14wgJV_PYeg@mail.gmail.com
