Commit Graph

5925 Commits

Author SHA1 Message Date
Tomas Vondra 41d2c6f952 Add missing index_insert_cleanup calls
The optimization for inserts into BRIN indexes added by c1ec02be1d
relies on a cache that needs to be explicitly released after calling
index_insert(). The commit however failed to invoke the cleanup in
validate_index(), which calls index_insert() indirectly through
table_index_validate_scan().

After inspecting index_insert() callers, it seems unique_key_recheck()
is missing the call too.

Fixed by adding the two missing index_insert_cleanup() calls.

The commit does two additional improvements. The aminsertcleanup()
signature is modified to have the index as the first argument, to make
it more like the other AM callbacks. And the aminsertcleanup() callback
is invoked even if the ii_AmCache is NULL, so that it can decide if the
cleanup is necessary.

Author: Alvaro Herrera, Tomas Vondra
Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/202401091043.e3nrqiad6gb7@alvherre.pgsql
2024-04-19 16:08:34 +02:00
Alvaro Herrera 0cd711271d
Better handle indirect constraint drops
It is possible for certain cases to remove not-null constraints without
maintaining the attnotnull in its correct state; for example if you drop
a column that's part of the primary key, and the other columns of the PK don't
have not-null constraints, then we should reset the attnotnull flags for
those other columns; up to this commit, we didn't.  Handle those cases
better by doing the attnotnull reset in RemoveConstraintById() instead
of in dropconstraint_internal().

However, there are some cases where we must not do so.  For example if
those other columns are in replica identity indexes or are generated
identity columns, we must keep attnotnull set, even though it results in
the catalog inconsistency that no not-null constraint supports that.

Because the attnotnull reset now happens in more places than before, for
instance when a column of the primary key changes type, we need an
additional trick to reinstate it as necessary.  Introduce a new
alter-table pass that does this, which needs simply reschedule some
AT_SetAttNotNull subcommands that were already being generated and
ignored.

Because of the exceptions in which attnotnull is not reset noted above,
we also include a pg_dump hack to include a not-null constraint when the
attnotnull flag is set even if no pg_constraint row exists.  This part
is undesirable but necessary, because failing to handle the case can
result in unrestorable dumps.

Reported-by: Tender Wang <tndrwang@gmail.com>
Co-authored-by: Tender Wang <tndrwang@gmail.com>
Reviewed-by: jian he <jian.universality@gmail.com>
Discussion: https://postgr.es/m/CAHewXN=hMbNa3d43NOR=OCgdgpTt18S-1fmueCoEGesyeK4bqw@mail.gmail.com
2024-04-19 12:37:33 +02:00
Daniel Gustafsson 950d4a2cb1 Fix typos and duplicate words
This fixes various typos, duplicated words, and tiny bits of whitespace
mainly in code comments but also in docs.

Author: Daniel Gustafsson <daniel@yesql.se>
Author: Heikki Linnakangas <hlinnaka@iki.fi>
Author: Alexander Lakhin <exclusion@gmail.com>
Author: David Rowley <dgrowleyml@gmail.com>
Author: Nazir Bilal Yavuz <byavuz81@gmail.com>
Discussion: https://postgr.es/m/3F577953-A29E-4722-98AD-2DA9EFF2CBB8@yesql.se
2024-04-18 21:28:07 +02:00
Alvaro Herrera d9f686a72e
Fix restore of not-null constraints with inheritance
In tables with primary keys, pg_dump creates tables with primary keys by
initially dumping them with throw-away not-null constraints (marked "no
inherit" so that they don't create problems elsewhere), to later drop
them once the primary key is restored.  Because of a unrelated
consideration, on tables with children we add not-null constraints to
all columns of the primary key when it is created.

If both a table and its child have primary keys, and pg_dump happens to
emit the child table first (and its throw-away not-null) and later its
parent table, the creation of the parent's PK will fail because the
throw-away not-null constraint collides with the permanent not-null
constraint that the PK wants to add, so the dump fails to restore.

We can work around this problem by letting the primary key "take over"
the child's not-null.  This requires no changes to pg_dump, just two
changes to ALTER TABLE: first, the ability to convert a no-inherit
not-null constraint into a regular inheritable one (including recursing
down to children, if there are any); second, the ability to "drop" a
constraint that is defined both directly in the table and inherited from
a parent (which simply means to mark it as no longer having a local
definition).

Secondarily, change ATPrepAddPrimaryKey() to acquire locks all the way
down the inheritance hierarchy, in case we need to recurse when
propagating constraints.

These two changes allow pg_dump to reproduce more cases involving
inheritance from versions 16 and older.

Lastly, make two changes to pg_dump: 1) do not try to drop a not-null
constraint that's marked as inherited; this allows a dump to restore
with no errors if a table with a PK inherits from another which also has
a PK; 2) avoid giving inherited constraints throwaway names, for the
rare cases where such a constraint survives after the restore.

Reported-by: Andrew Bille <andrewbille@gmail.com>
Reported-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/CAJnzarwkfRu76_yi3dqVF_WL-MpvT54zMwAxFwJceXdHB76bOA@mail.gmail.com
Discussion: https://postgr.es/m/Zh0aAH7tbZb-9HbC@pryzbyj2023
2024-04-18 15:35:15 +02:00
Amit Langote 2c7cea5a8e Fix object name clash in recently introduced test
c0fc075186 wasn't careful about naming the DOMAIN used in some new
tests in sqljson_queryfunc.sql so as not to clash with the name of a
DOMAIN used in the nearby sqljson_jsontable.sql.  Fix by using a
different name for the newly added DOMAIN in sqljson_queryfuncs.sql.

Per buildfarm members canebrake and urutu.

Discussion: https://postgr.es/m/CA+HiwqEjkbDxqqD3VJamc6R9+B102H7=SFYYOM7gKrxzJO35TQ@mail.gmail.com
2024-04-18 17:28:12 +09:00
Amit Langote c0fc075186 SQL/JSON: Fix issues with DEFAULT .. ON ERROR / EMPTY
SQL/JSON query functions allow specifying an expression to return
when either of ON ERROR or ON EMPTY condition occurs when evaluating
the JSON path expression.  The parser (transformJsonBehavior()) checks
that the specified expression is one of the supported expressions, but
there are two issues with how the check is done that are fixed in this
commit:

* No check for some expressions related to coercion, such as
  CoerceViaIO, that may appear in the transformed user-specified
  expressions that include cast(s)

* An unsupported expression may be masked by a coercion-related
  expression, which must be flagged by checking the latter's
  argument expression recursively

Author: Jian He <jian.universality@gmail.com>
Author: Amit Langote <amitlangote09@gmail.com>
Reported-by: Jian He <jian.universality@gmail.com>
Discussion: https://postgr.es/m/CACJufxEqhqsfrg_p7EMyo5zak3d767iFDL8vz_4%3DZBHpOtrghw@mail.gmail.com
Discussion: https://postgr.es/m/CACJufxGOerH1QJknm1noh-Kz5FqU4p7QfeZSeVT2tN_4SLXYNg@mail.gmail.com
2024-04-18 14:46:35 +09:00
Amit Langote b4fad46b6b SQL/JSON: Improve some error messages
This improves some error messages emitted by SQL/JSON query functions
by mentioning column name when available, such as when they are
invoked as part of evaluating JSON_TABLE() columns.  To do so, a new
field column_name is added to both JsonFuncExpr and JsonExpr that is
only populated when creating those nodes for transformed JSON_TABLE()
columns.

While at it, relevant error messages are reworded for clarity.

Reported-by: Jian He <jian.universality@gmail.com>
Suggested-by: Jian He <jian.universality@gmail.com>
Discussion: https://postgr.es/m/CACJufxG_e0QLCgaELrr2ZNz7AxPeGCNKAORe3fHtFCQLsH4J4Q@mail.gmail.com
2024-04-18 14:45:48 +09:00
David Rowley 6d2fd66b99 Push dedicated BumpBlocks to the tail of the blocks list
BumpContext relies on using the head block from its 'blocks' field to
use as the current block to allocate new chunks to.  When we receive an
allocation request larger than allocChunkLimit, we place these chunks on
a new dedicated block and, until now, we pushed the block onto the
*head* of the 'blocks' list.

This behavior caused the previous bump block to no longer be available
for new normal-sized (non-large) allocations and would result in blocks
only being partially filled if a large allocation request arrived before
the block became full.

Here adjust the code to push these dedicated blocks onto the *tail* of
the blocks list so that the head block remains intact and available to
be used by normal allocation request sizes until it becomes full.

In passing, make the elog(ERROR) calls for the unsupported callbacks
consistent.  Likewise for the header comments for those functions.

Discussion: https://postgr.es/m/CAApHDvp9___r-ayJj0nZ6GD3MeCGwGZ0_6ZptWpwj+zqHtmwCw@mail.gmail.com
Discussion: https://postgr.es/m/CAApHDvqerXpzUnuDQfUEi3DZA+9=Ud9WSt3ruxN5b6PcOosx2g@mail.gmail.com
2024-04-17 10:40:31 +12:00
David Rowley bea97cd02e Improve test coverage in bump.c
There were no callers of BumpAllocLarge() in the regression tests, so
here we add a sort with a tuple large enough to use that path in bump.c.

Also, BumpStats() wasn't being called, so add a test to sysviews.sql to
call pg_backend_memory_contexts() while a bump context exists in the
backend.

Reported-by: Andres Freund
Discussion: https://postgr.es/m/20240414223305.m3i5eju6zylabvln@awork3.anarazel.de
2024-04-16 16:21:31 +12:00
Tom Lane e0df80828a Fix type-checking of RECORD-returning functions in FROM, redux.
Commit 2ed8f9a01 intended to institute a policy that if a
RangeTblFunction has a coldeflist, then the function return type is
certainly RECORD, and we should use the coldeflist as the source of
truth about what the columns of the record type are.  When the
original function has been folded to a constant, inspection of the
constant might give a different answer.  This situation will lead to
a tuple-type-mismatch error at execution, but up until that point we
need to consistently believe the coldeflist, or we'll have problems
from different bits of code reaching different conclusions.

expandRTE didn't get that memo though, and would try to produce a
tupdesc based on the constant in this situation, leading to an
assertion failure.  (Desultory testing suggests that non-assert
builds often manage to give the expected error, although I also
saw a "cache lookup failed for type 0" error, and it seems at
least possible that a crash could happen.)

Some other callers of get_expr_result_type and get_expr_result_tupdesc
were also being incautious about this.  While none of them seem to
have actual bugs, they're working harder than necessary in this case,
besides which it seems safest to have an explicit policy of not using
those functions on an RTE with a coldeflist.  Adjust the code
accordingly, and add commentary to funcapi.c about this policy.

Also fix an obsolete comment that claimed "get_expr_result_type()
doesn't know how to extract type info from a RECORD constant".
That hasn't been true since commit d57534740.

Per bug #18422 from Alexander Lakhin.
As with the previous commit, back-patch to all supported branches.

Discussion: https://postgr.es/m/18422-89ca86c8eac5246d@postgresql.org
2024-04-15 12:56:56 -04:00
Alvaro Herrera cee8db3f68
ATTACH PARTITION: Don't match a PK with a UNIQUE constraint
When matching constraints in AttachPartitionEnsureIndexes() we weren't
testing the constraint type, which could make a UNIQUE key lacking a
not-null constraint incorrectly satisfy a primary key requirement.  Fix
this by testing that the constraint types match.  (Other possible
mismatches are verified by comparing index properties.)

Discussion: https://postgr.es/m/202402051447.wimb4xmtiiyb@alvherre.pgsql
2024-04-15 15:07:47 +02:00
Alexander Korotkov 9dfcac8e15 Grammar fixes for split/merge partitions code
The fixes relate to comments, error messages, and corresponding expected output
of regression tests.

Discussion: https://postgr.es/m/CAMbWs49DDsknxyoycBqiE72VxzL_sYHF6zqL8dSeNehKPJhkKg%40mail.gmail.com
Discussion: https://postgr.es/m/86bfd241-a58c-479a-9a72-2c67a02becf8%40postgrespro.ru
Discussion: https://postgr.es/m/CAHewXNkGMPU50QG7V6Q60JGFORfo8LfYO1_GCkCa0VWbmB-fEw%40mail.gmail.com
Author: Richard Guo, Dmitry Koval, Tender Wang
2024-04-15 16:00:02 +03:00
Alvaro Herrera c3709100be
Fix propagating attnotnull in multiple inheritance
In one of the many strange corner cases of multiple inheritance being
used, commit b0e96f3119 missed a CommandCounterIncrement() call after
updating the attnotnull flag during ALTER TABLE ADD COLUMN, which caused
a catalog tuple to be update attempted twice in the same command, giving
rise to a "tuple already updated by self" error.  Add the missing call
to solve that, and a test case that reproduces the scenario.

As a (perhaps surprising) secondary effect, this CCI addition triggers
another behavior change: when a primary key is added to a parent
partitioned table and the column in an existing partition does not have
a not-null constraint, we no longer error out.  This will probably be a
welcome change by some users, and I think it's unlikely that anybody
will miss the old behavior.

Reported-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: http://postgr.es/m/045dec3f-9b3d-aa44-0c99-85f6992306c7@gmail.com
2024-04-15 12:20:56 +02:00
Peter Eisentraut 6ff21c0530 psql: Make output of \dD more stable
\dD showed domain check constraints in arbitrary order, which can
cause regression test failures, which was exposed by commit
9895b35cb8.  To fix, order the constraints by conname, which matches
what psql does in other queries listing constraints.
2024-04-15 09:28:48 +02:00
Peter Eisentraut 9895b35cb8 Fix ALTER DOMAIN NOT NULL syntax
This addresses a few problems with commit e5da0fe3c2 ("Catalog domain
not-null constraints").

In CREATE DOMAIN, a NOT NULL constraint looks like

    CREATE DOMAIN d1 AS int [ CONSTRAINT conname ] NOT NULL

(Before e5da0fe3c2, the constraint name was accepted but ignored.)

But in ALTER DOMAIN, a NOT NULL constraint looks like

    ALTER DOMAIN d1 ADD [ CONSTRAINT conname ] NOT NULL VALUE

where VALUE is where for a table constraint the column name would be.
(This works as of e5da0fe3c2.  Before e5da0fe3c2, this syntax
resulted in an internal error.)

But for domains, this latter syntax is confusing and needlessly
inconsistent between CREATE and ALTER.  So this changes it to just

    ALTER DOMAIN d1 ADD [ CONSTRAINT conname ] NOT NULL

(None of these syntaxes are per SQL standard; we are just living with
the bits of inconsistency that have built up over time.)

In passing, this also changes the psql \dD output to not show not-null
constraints in the column "Check", since it's already shown in the
column "Nullable".  This has also been off since e5da0fe3c2.

Reviewed-by: jian he <jian.universality@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/9ec24d7b-633d-463a-84c6-7acff769c9e8%40eisentraut.org
2024-04-15 08:34:45 +02:00
David Rowley 3af7040985 Fix IS [NOT] NULL qual optimization for inheritance tables
b262ad440 added code to have the planner remove redundant IS NOT NULL
quals and eliminate needless scans for IS NULL quals on tables where the
qual's column has a NOT NULL constraint.

That commit failed to consider that an inheritance parent table could
have differing NOT NULL constraints between the parent and the child.
This caused issues as if we eliminated a qual on the parent, when
applying the quals to child tables in apply_child_basequals(), the qual
might not have been added to the parent's baserestrictinfo.

Here we fix this by not applying the optimization to remove redundant
quals to RelOptInfos belonging to inheritance parents and applying the
optimization again in apply_child_basequals().  Effectively, this means
that the parent and child are considered independently as the parent has
both an inh=true and inh=false RTE and we still apply the optimization
to the RelOptInfo corresponding to the inh=false RTE.

We're able to still apply the optimization in add_base_clause_to_rel()
for partitioned tables as the NULLability of partitions must match that
of their parent.  And, if we ever expand restriction_is_always_false()
and restriction_is_always_true() to handle partition constraints then we
can apply the same logic as, even in multi-level partitioned tables,
there's no way to route values to a partition when the qual does not
match the partition qual of the partitioned table's parent partition.
The same is true for CHECK constraints as those must also match between
arent partitioned tables and their partitions.

Author: Richard Guo, David Rowley
Discussion: https://postgr.es/m/CAMbWs4930gQSZmjR7aANzEapdy61gCg6z8dT-kAEYD0sYWKPdQ@mail.gmail.com
2024-04-12 20:07:53 +12:00
Tom Lane 5392dd3d2a Fix plpgsql's handling of -- comments following expressions.
Up to now, read_sql_construct() has collected all the source text from
the statement or expression's initial token up to the character just
before the "until" token.  It normally tries to strip trailing
whitespace from that, largely for neatness.  If there was a "-- text"
comment after the expression, this resulted in removing the newline
that terminates the comment, which creates a hazard if we try to paste
the collected text into a larger SQL construct without inserting a
newline after it.  In particular this caused our handling of CASE
constructs to fail if there's a comment after a WHEN expression.

Commit 4adead1d2 noticed a similar problem with cursor arguments,
and worked around it through the rather crude hack of suppressing
the whitespace-trimming behavior for those.  Rather than do that
and leave the hazard open for future hackers to trip over, let's
fix it properly.  pl_scanner.c already has enough infrastructure
to report the end location of the expression's last token, so
we can copy up to that location and never collect any trailing
whitespace or comment to begin with.

Erik Wienhold and Tom Lane, per report from Michal Bartak.
Back-patch to all supported branches.

Discussion: https://postgr.es/m/CAAVzF_FjRoi8fOVuLCZhQJx6HATQ7MKm=aFOHWZODFnLmjX-xA@mail.gmail.com
2024-04-10 15:45:58 -04:00
Alexander Korotkov ff9f72c68f revert: Transform OR clauses to ANY expression
This commit reverts 72bd38cc99 due to implementation and design issues.

Reported-by: Tom Lane
Discussion: https://postgr.es/m/3604469.1712628736%40sss.pgh.pa.us
2024-04-10 02:28:09 +03:00
Alexander Korotkov c99ef1811a Checks for ALTER TABLE ... SPLIT/MERGE PARTITIONS ... commands
Check that the target partition actually belongs to the parent table.

Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/cd842601-cf1a-9806-f7b7-d2509b93ba61%40gmail.com
Author: Dmitry Koval
2024-04-10 01:47:21 +03:00
Alexander Korotkov df64c81ca9 Fix some grammer errors from error messages and codes comments
Discussion: https://postgr.es/m/CAHewXNkGMPU50QG7V6Q60JGFORfo8LfYO1_GCkCa0VWbmB-fEw%40mail.gmail.com
Author: Tender Wang
2024-04-08 14:39:41 +03:00
Amit Langote bb766cde63 JSON_TABLE: Add support for NESTED paths and columns
A NESTED path allows to extract data from nested levels of JSON
objects given by the parent path expression, which are projected as
columns specified using a nested COLUMNS clause, just like the parent
COLUMNS clause.  Rows comprised from a NESTED columns are "joined"
to the row comprised from the parent columns.  If a particular NESTED
path evaluates to 0 rows, then the nested COLUMNS will emit NULLs,
making it an OUTER join.

NESTED columns themselves may include NESTED paths to allow
extracting data from arbitrary nesting levels, which are likewise
joined against the rows at the parent level.

Multiple NESTED paths at a given level are called "sibling" paths
and their rows are combined by UNIONing them, that is, after being
joined against the parent row as described above.

Author: Nikita Glukhov <n.gluhov@postgrespro.ru>
Author: Teodor Sigaev <teodor@sigaev.ru>
Author: Oleg Bartunov <obartunov@gmail.com>
Author: Alexander Korotkov <aekorotkov@gmail.com>
Author: Andrew Dunstan <andrew@dunslane.net>
Author: Amit Langote <amitlangote09@gmail.com>
Author: Jian He <jian.universality@gmail.com>

Reviewers have included (in no particular order):

Andres Freund, Alexander Korotkov, Pavel Stehule, Andrew Alsup,
Erik Rijkers, Zihong Yu, Himanshu Upadhyaya, Daniel Gustafsson,
Justin Pryzby, Álvaro Herrera, Jian He

Discussion: https://postgr.es/m/cd0bb935-0158-78a7-08b5-904886deac4b@postgrespro.ru
Discussion: https://postgr.es/m/20220616233130.rparivafipt6doj3@alap3.anarazel.de
Discussion: https://postgr.es/m/abd9b83b-aa66-f230-3d6d-734817f0995d%40postgresql.org
Discussion: https://postgr.es/m/CA+HiwqE4XTdfb1nW=Ojoy_tQSRhYt-q_kb6i5d4xcKyrLC1Nbg@mail.gmail.com
2024-04-08 16:14:13 +09:00
Amit Langote f6a2529920 Fix JsonExpr deparsing to emit QUOTES and WRAPPER correctly
Currently, get_json_expr_options() does not emit the default values
for QUOTES (KEEP QUOTES) and WRAPPER (WITHOUT WRAPPER).  That causes
the deparsed JSON_TABLE() columns, such as those contained in a a
view's query, to behave differently when executed than the original
definition.  That's because the rules encoded in
transformJsonTableColumns() will choose either JSON_VALUE() or
JSON_QUERY() as implementation to execute a given column's path
expression depending on the QUOTES and WRAPPER specificationd and
they have slightly different semantics.

Reported-by: Jian He <jian.universality@gmail.com>
Discussion: https://postgr.es/m/CACJufxEqhqsfrg_p7EMyo5zak3d767iFDL8vz_4%3DZBHpOtrghw%40mail.gmail.com
2024-04-08 16:14:12 +09:00
Amit Langote 561b74ddb8 Fix restriction on specifying KEEP QUOTES in JSON_QUERY()
Currently, transformJsonFuncExpr() enforces some restrictions on
the combinations of QUOTES and WRAPPER clauses that can be specified
in JSON_QUERY().  The intent was to only prevent the useless
combination WITH WRAPPER OMIT QUOTES, but the coding prevented KEEP
QUOTES too, which is not helpful. Fix that.
2024-04-08 16:02:29 +09:00
Alexander Korotkov 72bd38cc99 Transform OR clauses to ANY expression
Replace (expr op C1) OR (expr op C2) ... with expr op ANY(ARRAY[C1, C2, ...])
on the preliminary stage of optimization when we are still working with the
expression tree.

Here Cn is a n-th constant expression, 'expr' is non-constant expression, 'op'
is an operator which returns boolean result and has a commuter (for the case
of reverse order of constant and non-constant parts of the expression,
like 'Cn op expr').

Sometimes it can lead to not optimal plan.  This is why there is a
or_to_any_transform_limit GUC.  It specifies a threshold value of length of
arguments in an OR expression that triggers the OR-to-ANY transformation.
Generally, more groupable OR arguments mean that transformation will be more
likely to win than to lose.

Discussion: https://postgr.es/m/567ED6CA.2040504%40sigaev.ru
Author: Alena Rybakina <lena.ribackina@yandex.ru>
Author: Andrey Lepikhov <a.lepikhov@postgrespro.ru>
Reviewed-by: Peter Geoghegan <pg@bowt.ie>
Reviewed-by: Ranier Vilela <ranier.vf@gmail.com>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Jian He <jian.universality@gmail.com>
2024-04-08 01:27:52 +03:00
Nathan Bossart 792752af4e Optimize pg_popcount() with AVX-512 instructions.
Presently, pg_popcount() processes data in 32-bit or 64-bit chunks
when possible.  Newer hardware that supports AVX-512 instructions
can use 512-bit chunks, which provides a nice speedup, especially
for larger buffers.  This commit introduces the infrastructure
required to detect compiler and CPU support for the required
AVX-512 intrinsic functions, and it adds a new pg_popcount()
implementation that uses these functions.  If CPU support for this
optimized implementation is detected at runtime, a function pointer
is updated so that it is used by subsequent calls to pg_popcount().

Most of the existing in-tree calls to pg_popcount() should benefit
from these instructions, and calls with smaller buffers should at
least not regress compared to v16.  The new infrastructure
introduced by this commit can also be used to optimize
visibilitymap_count(), but that is left for a follow-up commit.

Co-authored-by: Paul Amonson, Ants Aasma
Reviewed-by: Matthias van de Meent, Tom Lane, Noah Misch, Akash Shankaran, Alvaro Herrera, Andres Freund, David Rowley
Discussion: https://postgr.es/m/BL1PR11MB5304097DF7EA81D04C33F3D1DCA6A%40BL1PR11MB5304.namprd11.prod.outlook.com
2024-04-06 21:56:23 -05:00
Tom Lane beb012b42f Disable parallel query in psql error-with-FETCH_COUNT test.
The buildfarm members using debug_parallel_query = regress are mostly
unhappy with this test.  I guess what is happening is that rows
generated by a parallel worker are buffered, and might or might not
get to the leader before the expected error occurs.  We did not see
any variability in the old version of this test because each FETCH
would succeed or fail atomically, leading to a predictable number of
rows emitted before failure.  I don't find this to be a bug, just
unspecified behavior, so let's disable parallel query for this one
test case to make the results stable.
2024-04-06 21:49:24 -04:00
Tom Lane 90f5178211 Re-implement psql's FETCH_COUNT feature atop libpq's chunked mode.
Formerly this was done with a cursor, which is problematic since
not all result-set-returning query types can be put into a cursor.
The new implementation is better integrated into other psql
features, too.

Daniel Vérité, reviewed by Laurenz Albe and myself (and whacked
around a bit by me, so any remaining bugs are my fault)

Discussion: https://postgr.es/m/CAKZiRmxsVTkO928CM+-ADvsMyePmU3L9DQCa9NwqjvLPcEe5QA@mail.gmail.com
2024-04-06 20:45:11 -04:00
Alexander Korotkov 87c21bb941 Implement ALTER TABLE ... SPLIT PARTITION ... command
This new DDL command splits a single partition into several parititions.
Just like ALTER TABLE ... MERGE PARTITIONS ... command, new patitions are
created using createPartitionTable() function with parent partition as the
template.

This commit comprises quite naive implementation which works in single process
and holds the ACCESS EXCLUSIVE LOCK on the parent table during all the
operations including the tuple routing.  This is why this new DDL command
can't be recommended for large partitioned tables under a high load.  However,
this implementation come in handy in certain cases even as is.
Also, it could be used as a foundation for future implementations with lesser
locking and possibly parallel.

Discussion: https://postgr.es/m/c73a1746-0cd0-6bdd-6b23-3ae0b7c0c582%40postgrespro.ru
Author: Dmitry Koval
Reviewed-by: Matthias van de Meent, Laurenz Albe, Zhihong Yu, Justin Pryzby
Reviewed-by: Alvaro Herrera, Robert Haas, Stephane Tachoires
2024-04-07 01:18:44 +03:00
Alexander Korotkov 1adf16b8fb Implement ALTER TABLE ... MERGE PARTITIONS ... command
This new DDL command merges several partitions into the one partition of the
target table.  The target partition is created using new
createPartitionTable() function with parent partition as the template.

This commit comprises quite naive implementation which works in single process
and holds the ACCESS EXCLUSIVE LOCK on the parent table during all the
operations including the tuple routing.  This is why this new DDL command
can't be recommended for large partitioned tables under a high load.  However,
this implementation come in handy in certain cases even as is.
Also, it could be used as a foundation for future implementations with lesser
locking and possibly parallel.

Discussion: https://postgr.es/m/c73a1746-0cd0-6bdd-6b23-3ae0b7c0c582%40postgrespro.ru
Author: Dmitry Koval
Reviewed-by: Matthias van de Meent, Laurenz Albe, Zhihong Yu, Justin Pryzby
Reviewed-by: Alvaro Herrera, Robert Haas, Stephane Tachoires
2024-04-07 01:18:43 +03:00
Peter Geoghegan 5bf748b86b Enhance nbtree ScalarArrayOp execution.
Commit 9e8da0f7 taught nbtree to handle ScalarArrayOpExpr quals
natively.  This works by pushing down the full context (the array keys)
to the nbtree index AM, enabling it to execute multiple primitive index
scans that the planner treats as one continuous index scan/index path.
This earlier enhancement enabled nbtree ScalarArrayOp index-only scans.
It also allowed scans with ScalarArrayOp quals to return ordered results
(with some notable restrictions, described further down).

Take this general approach a lot further: teach nbtree SAOP index scans
to decide how to execute ScalarArrayOp scans (when and where to start
the next primitive index scan) based on physical index characteristics.
This can be far more efficient.  All SAOP scans will now reliably avoid
duplicative leaf page accesses (just like any other nbtree index scan).
SAOP scans whose array keys are naturally clustered together now require
far fewer index descents, since we'll reliably avoid starting a new
primitive scan just to get to a later offset from the same leaf page.

The scan's arrays now advance using binary searches for the array
element that best matches the next tuple's attribute value.  Required
scan key arrays (i.e. arrays from scan keys that can terminate the scan)
ratchet forward in lockstep with the index scan.  Non-required arrays
(i.e. arrays from scan keys that can only exclude non-matching tuples)
"advance" without the process ever rolling over to a higher-order array.

Naturally, only required SAOP scan keys trigger skipping over leaf pages
(non-required arrays cannot safely end or start primitive index scans).
Consequently, even index scans of a composite index with a high-order
inequality scan key (which we'll mark required) and a low-order SAOP
scan key (which we won't mark required) now avoid repeating leaf page
accesses -- that benefit isn't limited to simpler equality-only cases.
In general, all nbtree index scans now output tuples as if they were one
continuous index scan -- even scans that mix a high-order inequality
with lower-order SAOP equalities reliably output tuples in index order.
This allows us to remove a couple of special cases that were applied
when building index paths with SAOP clauses during planning.

Bugfix commit 807a40c5 taught the planner to avoid generating unsafe
path keys: path keys on a multicolumn index path, with a SAOP clause on
any attribute beyond the first/most significant attribute.  These cases
are now all safe, so we go back to generating path keys without regard
for the presence of SAOP clauses (just like with any other clause type).
Affected queries can now exploit scan output order in all the usual ways
(e.g., certain "ORDER BY ... LIMIT n" queries can now terminate early).

Also undo changes from follow-up bugfix commit a4523c5a, which taught
the planner to produce alternative index paths, with path keys, but
without low-order SAOP index quals (filter quals were used instead).
We'll no longer generate these alternative paths, since they can no
longer offer any meaningful advantages over standard index qual paths.
Affected queries thereby avoid all of the disadvantages that come from
using filter quals within index scan nodes.  They can avoid extra heap
page accesses from using filter quals to exclude non-matching tuples
(index quals will never have that problem).  They can also skip over
irrelevant sections of the index in more cases (though only when nbtree
determines that starting another primitive scan actually makes sense).

There is a theoretical risk that removing restrictions on SAOP index
paths from the planner will break compatibility with amcanorder-based
index AMs maintained as extensions.  Such an index AM could have the
same limitations around ordered SAOP scans as nbtree had up until now.
Adding a pro forma incompatibility item about the issue to the Postgres
17 release notes seems like a good idea.

Author: Peter Geoghegan <pg@bowt.ie>
Author: Matthias van de Meent <boekewurm+postgres@gmail.com>
Reviewed-By: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-By: Matthias van de Meent <boekewurm+postgres@gmail.com>
Reviewed-By: Tomas Vondra <tomas.vondra@enterprisedb.com>
Discussion: https://postgr.es/m/CAH2-Wz=ksvN_sjcnD1+Bt-WtifRA5ok48aDYnq3pkKhxgMQpcw@mail.gmail.com
2024-04-06 11:47:10 -04:00
Amit Langote de3600452b Add basic JSON_TABLE() functionality
JSON_TABLE() allows JSON data to be converted into a relational view
and thus used, for example, in a FROM clause, like other tabular
data.  Data to show in the view is selected from a source JSON object
using a JSON path expression to get a sequence of JSON objects that's
called a "row pattern", which becomes the source to compute the
SQL/JSON values that populate the view's output columns.  Column
values themselves are computed using JSON path expressions applied to
each of the JSON objects comprising the "row pattern", for which the
SQL/JSON query functions added in 6185c9737c are used.

To implement JSON_TABLE() as a table function, this augments the
TableFunc and TableFuncScanState nodes that are currently used to
support XMLTABLE() with some JSON_TABLE()-specific fields.

Note that the JSON_TABLE() spec includes NESTED COLUMNS and PLAN
clauses, which are required to provide more flexibility to extract
data out of nested JSON objects, but they are not implemented here
to keep this commit of manageable size.

Author: Nikita Glukhov <n.gluhov@postgrespro.ru>
Author: Teodor Sigaev <teodor@sigaev.ru>
Author: Oleg Bartunov <obartunov@gmail.com>
Author: Alexander Korotkov <aekorotkov@gmail.com>
Author: Andrew Dunstan <andrew@dunslane.net>
Author: Amit Langote <amitlangote09@gmail.com>
Author: Jian He <jian.universality@gmail.com>

Reviewers have included (in no particular order):

Andres Freund, Alexander Korotkov, Pavel Stehule, Andrew Alsup,
Erik Rijkers, Zihong Yu, Himanshu Upadhyaya, Daniel Gustafsson,
Justin Pryzby, Álvaro Herrera, Jian He

Discussion: https://postgr.es/m/cd0bb935-0158-78a7-08b5-904886deac4b@postgrespro.ru
Discussion: https://postgr.es/m/20220616233130.rparivafipt6doj3@alap3.anarazel.de
Discussion: https://postgr.es/m/abd9b83b-aa66-f230-3d6d-734817f0995d%40postgresql.org
Discussion: https://postgr.es/m/CA+HiwqE4XTdfb1nW=Ojoy_tQSRhYt-q_kb6i5d4xcKyrLC1Nbg@mail.gmail.com
2024-04-04 20:20:15 +09:00
Michael Paquier 85230a247c pg_regress: Save errno in emit_tap_output_v() and switch to %m
emit_tap_output_v() includes some fprintf() calls for some output
related to the TAP protocol, that may clobber errno and break %m.  This
commit makes the logging of pg_regress smarter by saving errno before
restoring it in vfprintf() where the input strings are used, removing
the need for strerror().  All logs are switched to %m rather than
strerror(), shaving some code.

This was not a problem until now as pg_regress.c did not use %m, but the
change is simple enough that we have no reason to not support this
placeholder, and that will avoid future mistakes if new logs that
include %m are added.

Author: Dagfinn Ilmari Mannsåker
Reviewed-by: Peter Eisentraunt, Michael Paquier
Discussion: https://postgr.es/m/87sf13jhuw.fsf@wibble.ilmari.org
2024-04-04 11:33:07 +09:00
Tom Lane 06286709ee Invent SERIALIZE option for EXPLAIN.
EXPLAIN (ANALYZE, SERIALIZE) allows collection of statistics about
the volume of data emitted by a query, as well as the time taken
to convert the data to the on-the-wire format.  Previously there
was no way to investigate this without actually sending the data
to the client, in which case network transmission costs might
swamp what you wanted to see.  In particular this feature allows
investigating the costs of de-TOASTing compressed or out-of-line
data during formatting.

Stepan Rutz and Matthias van de Meent,
reviewed by Tomas Vondra and myself

Discussion: https://postgr.es/m/ca0adb0e-fa4e-c37e-1cd7-91170b18cae1@gmx.de
2024-04-03 17:41:57 -04:00
Alvaro Herrera 13b3b62746
Don't use the pg_am system catalog in new test
This causes deadlocks because it's a highly trafficked catalog.  Use a
regular table created by the same test instead.

Discussion: https://postgr.es/m/f3e61e27-19d0-5e40-3eb2-53282fa0532a@gmail.com
2024-04-02 13:10:16 +02:00
Masahiko Sawada 667e65aac3 Use TidStore for dead tuple TIDs storage during lazy vacuum.
Previously, we used a simple array for storing dead tuple IDs during
lazy vacuum, which had a number of problems:

* The array used a single allocation and so was limited to 1GB.
* The allocation was pessimistically sized according to table size.
* Lookup with binary search was slow because of poor CPU cache and
  branch prediction behavior.

This commit replaces that array with the TID store from commit
30e144287a.

Since the backing radix tree makes small allocations as needed, the
1GB limit is now gone. Further, the total memory used is now often
smaller by an order of magnitude or more, depending on the
distribution of blocks and offsets. These two features should make
multiple rounds of heap scanning and index cleanup an extremely rare
event. TID lookup during index cleanup is also several times faster,
even more so when index order is correlated with heap tuple order.

Since there is no longer a predictable relationship between the number
of dead tuples vacuumed and the space taken up by their TIDs, the
number of tuples no longer provides any meaningful insights for users,
nor is the maximum number predictable. For that reason this commit
also changes to byte-based progress reporting, with the relevant
columns of pg_stat_progress_vacuum renamed accordingly to
max_dead_tuple_bytes and dead_tuple_bytes.

For parallel vacuum, both the TID store and supplemental information
specific to vacuum are shared among the parallel vacuum workers. As
with the previous array, we don't take any locks on TidStore during
parallel vacuum since writes are still only done by the leader
process.

Bump catalog version.

Reviewed-by: John Naylor, (in an earlier version) Dilip Kumar
Discussion: https://postgr.es/m/CAD21AoAfOZvmfR0j8VmZorZjL7RhTiQdVttNuC4W-Shdc2a-AA%40mail.gmail.com
2024-04-02 10:15:37 +09:00
David Rowley d5d2205c8d Fix assert failure when planning setop subqueries with CTEs
66c0185a3 adjusted the UNION planner to request that union child queries
produce Paths correctly ordered to implement the UNION by way of
MergeAppend followed by Unique.  The code there made a bad assumption
that if the root->parent_root->parse had setOperations set that the
query must be the child subquery of a set operation.  That's not true
when it comes to planning a non-inlined CTE which is parented by a set
operation.  This causes issues as the CTE's targetlist has no
requirement to match up to the SetOperationStmt's groupClauses

Fix this by adding a new parameter to both subquery_planner() and
grouping_planner() to explicitly pass the SetOperationStmt only when
planning set operation child subqueries.

Thank you to Tom Lane for helping to rationalize the decision on the
best function signature for subquery_planner().

Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/242fc7c6-a8aa-2daf-ac4c-0a231e2619c1@gmail.com
2024-04-02 12:15:45 +13:00
Masahiko Sawada f5a227895e Add new COPY option LOG_VERBOSITY.
This commit adds a new COPY option LOG_VERBOSITY, which controls the
amount of messages emitted during processing. Valid values are
'default' and 'verbose'.

This is currently used in COPY FROM when ON_ERROR option is set to
ignore. If 'verbose' is specified, a NOTICE message is emitted for
each discarded row, providing additional information such as line
number, column name, and the malformed value. This helps users to
identify problematic rows that failed to load.

Author: Bharath Rupireddy
Reviewed-by: Michael Paquier, Atsushi Torikoshi, Masahiko Sawada
Discussion: https://www.postgresql.org/message-id/CALj2ACUk700cYhx1ATRQyRw-fBM%2BaRo6auRAitKGff7XNmYfqQ%40mail.gmail.com
2024-04-01 15:25:25 +09:00
Tom Lane b154d8a6d0 Add pg_basetype() function to extract a domain's base type.
This SQL-callable function behaves much like our internal utility
function getBaseType(), except it returns NULL rather than failing for
an invalid type OID.  (That behavior is modeled on our experience with
other catalog-inquiry functions such as the ACL checking functions.)
The key advantage over doing a join to pg_type is that it will loop
as needed to find the bottom base type of a nest of domains.

Steve Chavez, reviewed by jian he and others

Discussion: https://postgr.es/m/CAGRrpzZSX8j=MQcbCSEisFA=ic=K3bknVfnFjAv1diVJxFHJvg@mail.gmail.com
2024-03-30 13:57:19 -04:00
Dean Rasheed 0294df2f1f Add support for MERGE ... WHEN NOT MATCHED BY SOURCE.
This allows MERGE commands to include WHEN NOT MATCHED BY SOURCE
actions, which operate on rows that exist in the target relation, but
not in the data source. These actions can execute UPDATE, DELETE, or
DO NOTHING sub-commands.

This is in contrast to already-supported WHEN NOT MATCHED actions,
which operate on rows that exist in the data source, but not in the
target relation. To make this distinction clearer, such actions may
now be written as WHEN NOT MATCHED BY TARGET.

Writing WHEN NOT MATCHED without specifying BY SOURCE or BY TARGET is
equivalent to writing WHEN NOT MATCHED BY TARGET.

Dean Rasheed, reviewed by Alvaro Herrera, Ted Yu and Vik Fearing.

Discussion: https://postgr.es/m/CAEZATCWqnKGc57Y_JanUBHQXNKcXd7r=0R4NEZUVwP+syRkWbA@mail.gmail.com
2024-03-30 10:00:26 +00:00
Tom Lane c2df2ed90a Try to stabilize flappy test result.
This recently-added test case checks the plan of an inner join
between two identical tables.  It's just chance which join order
the planner will pick, and in the presence of any variation in
the underlying statistics, the displayed plan might change.
Add a WHERE condition to break the cost symmetry and hopefully
stabilize matters.

(We're still trying to understand exactly why the underlying
statistics aren't as stable as intended, but this seems like
a good change anyway, since this test would surely bite us
again in future.)

While here, clean up assorted comment spelling, grammar, and
whitespace problems.

Discussion: https://postgr.es/m/4168116.1711720146@sss.pgh.pa.us
2024-03-29 10:40:31 -04:00
Tom Lane 0075d78947 Allow "internal" subtransactions in parallel mode.
Allow use of BeginInternalSubTransaction() in parallel mode, so long
as the subtransaction doesn't attempt to acquire an XID or increment
the command counter.  Given those restrictions, the other parallel
processes don't need to know about the subtransaction at all, so
this should be safe.  The benefit is that it allows subtransactions
intended for error recovery, such as pl/pgsql exception blocks,
to be used in PARALLEL SAFE functions.

Another reason for doing this is that the API of
BeginInternalSubTransaction() doesn't allow reporting failure.
pl/python for one, and perhaps other PLs, copes very poorly with an
error longjmp out of BeginInternalSubTransaction().  The headline
feature of this patch removes the only easily-triggerable failure
case within that function.  There remain some resource-exhaustion
and similar cases, which we now deal with by promoting them to FATAL
errors, so that callers need not try to clean up.  (It is likely
that such errors would leave us with corrupted transaction state
inside xact.c, making recovery difficult if not impossible anyway.)

Although this work started because of a report of a pl/python crash,
we're not going to do anything about that in the back branches.
Back-patching this particular fix is obviously not very wise.
While we could contemplate some narrower band-aid, pl/python is
already an untrusted language, so it seems okay to classify this
as a "so don't do that" case.

Patch by me, per report from Hao Zhang.  Thanks to Robert Haas for
review.

Discussion: https://postgr.es/m/CALY6Dr-2yLVeVPhNMhuBnRgOZo1UjoTETgtKBx1B2gUi8yy+3g@mail.gmail.com
2024-03-28 12:43:10 -04:00
Alvaro Herrera e2395cdbe8
ALTER TABLE: rework determination of access method ID
Avoid setting an access method OID for relation kinds that don't take
one.  Code review for new feature added in 374c7a2290.

Author: Justin Pryzby <pryzby@telsasoft.com>
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/e5516ac1-5264-c3c0-d822-9e6f614ea93b@gmail.com
2024-03-28 16:51:20 +01:00
David Rowley d6a6957d53 Fix unstable aggregate regression test
Buildfarm member avocet has shown a plan change by switching the
finalize aggregate stage to use a GroupAggregate rather than a
HashAggregate.  This is consistent with autovacuum having triggered on
the table, per analysis by Alexander Lakhin.

Fix this by disabling autovacuum on the table.

Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/d4493a28-589a-5328-fed5-250f2d7d3e2a@gmail.com
Backpatch-through: 16, where this test was added.
2024-03-28 00:13:48 +13:00
Dean Rasheed e6341323a8 Add functions to generate random numbers in a specified range.
This adds 3 new variants of the random() function:

    random(min integer, max integer) returns integer
    random(min bigint, max bigint) returns bigint
    random(min numeric, max numeric) returns numeric

Each returns a random number x in the range min <= x <= max.

For the numeric function, the number of digits after the decimal point
is equal to the number of digits that "min" or "max" has after the
decimal point, whichever has more.

The main entry points for these functions are in a new C source file.
The existing random(), random_normal(), and setseed() functions are
moved there too, so that they can all share the same PRNG state, which
is kept private to that file.

Dean Rasheed, reviewed by Jian He, David Zhang, Aleksander Alekseev,
and Tomas Vondra.

Discussion: https://postgr.es/m/CAEZATCV89Vxuq93xQdmc0t-0Y2zeeNQTdsjbmV7dyFBPykbV4Q@mail.gmail.com
2024-03-27 10:12:39 +00:00
Amit Kapila 6d49c8d4b4 Change last_inactive_time to inactive_since in pg_replication_slots.
Commit a11f330b55 added last_inactive_time to show the last time the slot
was inactive. But, it tells the last time that a currently-inactive slot
previously *WAS* active. This could be unclear, so we changed the name to
inactive_since.

Reported-by: Robert Haas
Author: Bharath Rupireddy
Reviewed-by: Bertrand Drouvot, Shveta Malik, Amit Kapila
Discussion: https://postgr.es/m/CA+Tgmob_Ta-t2ty8QrKHBGnNLrf4ZYcwhGHGFsuUoFrAEDw4sA@mail.gmail.com
Discussion: https://postgr.es/m/CALj2ACUXS0SfbHzsX8bqo+7CZhocsV52Kiu7OWGb5HVPAmJqnA@mail.gmail.com
2024-03-27 09:27:44 +05:30
Tom Lane fad3b5b5ac Fix failure of ALTER FOREIGN TABLE SET SCHEMA to move sequences.
Ordinary ALTER TABLE SET SCHEMA will also move any owned sequences
into the new schema.  We failed to do likewise for foreign tables,
because AlterTableNamespaceInternal believed that only certain
relkinds could have indexes, owned sequences, or constraints.
We could simply add foreign tables to that relkind list, but it
seems likely that the same oversight could be made again in
future.  Instead let's remove the relkind filter altogether.
These functions shouldn't cost much when there are no objects
that they need to process, and surely this isn't an especially
performance-critical case anyway.

Per bug #18407 from Vidushi Gupta.  Back-patch to all supported
branches.

Discussion: https://postgr.es/m/18407-4fd07373d252c6a0@postgresql.org
2024-03-26 15:28:31 -04:00
Tom Lane a65724dfa7 Propagate pathkeys from CTEs up to the outer query.
If we know the sort order of a CTE's output, and it is relevant
to the outer query, label the CTE's outer-query access path using
those pathkeys.  This may enable optimizations such as avoiding
a sort in the outer query.

The code for hoisting pathkeys into the outer query already exists
for regular RTE_SUBQUERY subqueries, but it wasn't getting used for
CTEs, possibly out of concern for maintaining an optimization fence
between the CTE and the outer query.  However, on the same arguments
used for commit f7816aec2, there seems no harm in letting the outer
query know what the inner query decided to do.

In support of this, we now remember the best Path as well as Plan
for each subquery for the rest of the planner run.  There may be
future applications for having that at hand, and it surely costs
little to build one more List.

Richard Guo (minor mods by me)

Discussion: https://postgr.es/m/CAMbWs49xYd3f8CrE8-WW3--dV1zH_sDSDn-vs2DzHj81Wcnsew@mail.gmail.com
2024-03-26 13:05:51 -04:00
Alvaro Herrera 374c7a2290
Allow specifying an access method for partitioned tables
It's now possible to specify a table access method via
CREATE TABLE ... USING for a partitioned table, as well change it with
ALTER TABLE ... SET ACCESS METHOD.  Specifying an AM for a partitioned
table lets the value be used for all future partitions created under it,
closely mirroring the behavior of the TABLESPACE option for partitioned
tables.  Existing partitions are not modified.

For a partitioned table with no AM specified, any new partitions are
created with the default_table_access_method.

Also add ALTER TABLE ... SET ACCESS METHOD DEFAULT, which reverts to the
original state of using the default for new partitions.

The relcache of partitioned tables is not changed: rd_tableam is not
set, even if a partitioned table has a relam set.

Author: Justin Pryzby <pryzby@telsasoft.com>
Author: Soumyadeep Chakraborty <soumyadeep2007@gmail.com>
Author: Michaël Paquier <michael@paquier.xyz>
Reviewed-by: The authors themselves
Discussion: https://postgr.es/m/CAE-ML+9zM4wJCGCBGv01k96qQ3gFv4WFcFy=zqPHKeaEFwwv6A@mail.gmail.com
Discussion: https://postgr.es/m/20210308010707.GA29832%40telsasoft.com
2024-03-25 16:30:36 +01:00
Amit Kapila a11f330b55 Track last_inactive_time in pg_replication_slots.
This commit adds a new property called last_inactive_time for slots. It is
set to 0 whenever a slot is made active/acquired and set to the current
timestamp whenever the slot is inactive/released or restored from the disk.
Note that we don't set the last_inactive_time for the slots currently being
synced from the primary to the standby because such slots are typically
inactive as decoding is not allowed on those.

The 'last_inactive_time' will be useful on production servers to debug and
analyze inactive replication slots. It will also help to know the lifetime
of a replication slot - one can know how long a streaming standby, logical
subscriber, or replication slot consumer is down.

The 'last_inactive_time' will also be useful to implement inactive
timeout-based replication slot invalidation in a future commit.

Author: Bharath Rupireddy
Reviewed-by: Bertrand Drouvot, Amit Kapila, Shveta Malik
Discussion: https://www.postgresql.org/message-id/CALj2ACW4aUe-_uFQOjdWCEN-xXoLGhmvRFnL8SNw_TZ5nJe+aw@mail.gmail.com
2024-03-25 16:34:33 +05:30
David Rowley 66c0185a3d Allow planner to use Merge Append to efficiently implement UNION
Until now, UNION queries have often been suboptimal as the planner has
only ever considered using an Append node and making the results unique
by either using a Hash Aggregate, or by Sorting the entire Append result
and running it through the Unique operator.  Both of these methods
always require reading all rows from the union subqueries.

Here we adjust the union planner so that it can request that each subquery
produce results in target list order so that these can be Merge Appended
together and made unique with a Unique node.  This can improve performance
significantly as the union child can make use of the likes of btree
indexes and/or Merge Joins to provide the top-level UNION with presorted
input.  This is especially good if the top-level UNION contains a LIMIT
node that limits the output rows to a small subset of the unioned rows as
cheap startup plans can be used.

Author: David Rowley
Reviewed-by: Richard Guo, Andy Fan
Discussion: https://postgr.es/m/CAApHDvpb_63XQodmxKUF8vb9M7CxyUyT4sWvEgqeQU-GB7QFoQ@mail.gmail.com
2024-03-25 14:31:14 +13:00