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Tom Lane 1f542a2eac Prevent planagg.c from failing on queries containing CTEs.
The existing tests in preprocess_minmax_aggregates() usually prevent it
from trying to do anything with queries containing CTEs, but there's an
exception: a CTE could be present as a member of an appendrel, if we
flattened a UNION ALL that contains CTE references.  If it did try to
generate an optimized path for a query using a CTE, it failed with
"could not find plan for CTE", as reported by Torsten Förtsch.

The proximate cause is an unwise decision in commit 3fc6e2d7f to clear
subroot->cte_plan_ids in build_minmax_path().  That left the subroot's
cte_plan_ids list out of step with its parse->cteList.

Removing the "subroot->cte_plan_ids = NIL;" assignment is enough to let
the case work again, but really it's pretty silly to be expending any
cycles at all in this module when there are CTEs: we always treat their
outputs as unordered so there's no way for the optimization to win.
Hence, also add an early-exit test so we don't waste time like that.

Back-patch to 9.6 where the misbehavior was introduced.

Report: https://postgr.es/m/CAKkG4_=gjY5QiHtqSZyWMwDuTd_CftKoTaCqxjJ7uUz1-Gw=qw@mail.gmail.com
2016-12-13 13:20:37 -05:00
config Fix python shlib probe for Cygwin. 2016-10-07 11:27:34 -04:00
contrib Fix race condition in test_decoding "slot" test. 2016-12-12 14:32:13 -05:00
doc doc: Improve documentation related to table partitioning feature. 2016-12-13 08:18:00 -05:00
src Prevent planagg.c from failing on queries containing CTEs. 2016-12-13 13:20:37 -05:00
.dir-locals.el emacs: Set indent-tabs-mode in perl-mode 2015-04-12 23:53:23 -04:00
.gitattributes Fix whitespace and remove obsolete gitattributes entry 2016-03-13 16:03:13 -04:00
.gitignore Allow .so minor version numbers above 9 in .gitignore. 2016-08-15 17:35:35 -04:00
aclocal.m4 Replace our hacked version of ax_pthread.m4 with latest upstream version. 2015-07-08 20:36:06 +03:00
configure Fix broken autoconf test for random number source. 2016-12-12 09:26:42 +02:00
configure.in Fix broken autoconf test for random number source. 2016-12-12 09:26:42 +02:00
COPYRIGHT Update copyright for 2016 2016-01-02 13:33:40 -05:00
GNUmakefile.in Have "make coverage" recurse into contrib as well 2016-09-05 18:44:36 -03:00
HISTORY Improve text of stub HISTORY file. 2014-02-12 18:16:17 -05:00
Makefile Allow make check in PL directories 2011-02-15 06:52:12 +02:00
README Don't generate plain-text HISTORY and src/test/regress/README anymore. 2014-02-10 20:48:04 -05:00
README.git Don't generate plain-text HISTORY and src/test/regress/README anymore. 2014-02-10 20:48:04 -05:00

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:

	http://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
http://www.postgresql.org/download/.  For more information look at our
web site located at http://www.postgresql.org/.