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Tom Lane b6423e92ab Doc: fix ancient mistake, or at least obsolete info, in rules example.
The example of expansion of multiple views claimed that the resulting
subquery nest would not get fully flattened because of an aggregate
function.  There's no aggregate in the example, though, only a user
defined function confusingly named MIN().  In a modern server, the
reason for the non-flattening is that MIN() is volatile, but I'm
unsure whether that was true back when this text was written.

Let's reduce the confusion level by using LEAST() instead (which
we didn't have at the time this example was created).  And then
we can just say that the planner will flatten the sub-queries, so
the rewrite system doesn't have to.

Noted by Paul Jungwirth.  This text is old enough to vote, so
back-patch to all supported branches.

Discussion: https://postgr.es/m/CA+renyXZFnmp9PcvX1EVR2dR=XG5e6E-AELr8AHCNZ8RYrpnPw@mail.gmail.com
2019-11-11 14:39:54 -05:00
config Simplify PGAC_STRUCT_TIMEZONE Autoconf macro 2019-10-07 16:47:23 +02:00
contrib Pass ItemPointer not HeapTuple to IndexBuildCallback. 2019-11-08 11:49:29 -08:00
doc Doc: fix ancient mistake, or at least obsolete info, in rules example. 2019-11-11 14:39:54 -05:00
src Further improve stability of partition_prune regression test. 2019-11-11 10:33:00 -05:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.gitattributes gitattributes: Remove entries for no longer existing files 2019-11-11 11:54:12 +01:00
.gitignore Support for optimizing and emitting code in LLVM JIT provider. 2018-03-22 11:05:22 -07:00
COPYRIGHT Update copyright for 2019 2019-01-02 12:44:25 -05:00
GNUmakefile.in Add "headerscheck" script to test header-file compilability under C. 2019-08-19 14:22:56 -04:00
HISTORY Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
Makefile Don't unset MAKEFLAGS in non-GNU Makefile. 2019-06-25 09:36:21 +12:00
README Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
README.git Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
aclocal.m4 Fix configure's AC_CHECK_DECLS tests to work correctly with clang. 2018-11-19 12:01:47 -05:00
configure Add backtrace support for error reporting 2019-11-08 15:44:20 -03:00
configure.in Add backtrace support for error reporting 2019-11-08 15:44:20 -03:00

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/.