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David Rowley 7e5d20bbd1 Disable run condition optimization for some WindowFuncs 
94985c210 added code to detect when WindowFuncs were monotonic and
allowed additional quals to be "pushed down" into the subquery to be
used as WindowClause runConditions in order to short-circuit execution
in nodeWindowAgg.c.

The Node representation of runConditions wasn't well selected and
because we do qual pushdown before planning the subquery, the planning
of the subquery could perform subquery pull-up of nested subqueries.
For WindowFuncs with args, the arguments could be changed after pushing
the qual down to the subquery.

This was made more difficult by the fact that the code duplicated the
WindowFunc inside an OpExpr to include in the WindowClauses runCondition
field.  This could result in duplication of subqueries and a pull-up of
such a subquery could result in another initplan parameter being issued
for the 2nd version of the subplan.  This could result in errors such as:

ERROR:  WindowFunc not found in subplan target lists

Here in the backbranches, we don't have the flexibility to improve the
Node representation to resolve this, so instead we just disable the
runCondition optimization for ntile() unless the argument is a Const,
(v16 only) and likewise for count(expr) (both v15 and v16).  count(*) is
unaffected.  All other window functions which support this optimization
all take zero arguments and therefore are unaffected.

Bug: #18170
Reported-by: Zuming Jiang
Discussion: https://postgr.es/m/18170-f1d17bf9a0d58b24@postgresql.org
Backpatch-through 15 (master will be fixed independently)
 		2024-05-01 16:35:37 +12:00
config Log LLVM library version in configure output. 2023-10-22 14:24:04 +13:00
contrib Make postgres_fdw request remote time zone 'GMT' not 'UTC'. 2024-04-21 13:46:20 -04:00
doc Doc: fix minor oversight in ALTER DEFAULT PRIVILEGES ref page. 2024-04-24 10:18:39 -04:00
src Disable run condition optimization for some WindowFuncs 2024-05-01 16:35:37 +12:00
.cirrus.star ci: Prepare to make compute resources for CI configurable 2023-08-23 15:15:29 -07:00
.cirrus.tasks.yml ci: macos: Choose python version 2024-03-25 13:14:31 -07:00
.cirrus.yml ci: Make compute resources for CI configurable 2023-08-23 15:15:29 -07:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.editorconfig Add .editorconfig 2019-12-18 09:13:13 +01:00
.git-blame-ignore-revs Backpatch addition of .git-blame-ignore-revs 2022-08-05 19:36:24 +02:00
.gitattributes Remove non-existing file from .gitattributes 2024-02-16 11:40:57 +01:00
.gitignore Add portlock directory to .gitignore 2022-11-26 07:47:01 -05:00
COPYRIGHT Update copyright for 2024 2024-01-03 20:49:04 -05:00
GNUmakefile.in Remove temporary portlock directory during make [dist]clean. 2022-11-26 10:30:46 -05:00
HISTORY Canonicalize some URLs 2020-02-10 20:47:50 +01:00
Makefile Dynamically find correct installation docs in Makefile. 2022-01-19 14:48:25 +01:00
README Canonicalize some URLs 2020-02-10 20:47:50 +01:00
README.git Canonicalize some URLs 2020-02-10 20:47:50 +01:00
aclocal.m4 Probe $PROVE not $PERL while checking for modules needed by TAP tests. 2021-11-22 12:54:52 -05:00
configure Stamp 15.6. 2024-02-05 16:43:21 -05:00
configure.ac Stamp 15.6. 2024-02-05 16:43:21 -05:00

README 

PostgreSQL Database Management System
=====================================

This directory contains the source code distribution of the PostgreSQL
database management system.

PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
transactions, foreign keys, subqueries, triggers, user-defined types
and functions.  This distribution also contains C language bindings.

PostgreSQL has many language interfaces, many of which are listed here:

	https://www.postgresql.org/download/

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
hardware platforms and contains information regarding any other
software packages that are required to build or run the PostgreSQL
system.  Copyright and license information can be found in the
file COPYRIGHT.  A comprehensive documentation set is included in this
distribution; it can be read as described in the installation
instructions.

The latest version of this software may be obtained at
https://www.postgresql.org/download/.  For more information look at our
web site located at https://www.postgresql.org/.