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Etsuro Fujita 7cfdc77023 Disable support for partitionwise joins in problematic cases.
Commit f49842d, which added support for partitionwise joins, built the
child's tlist by applying adjust_appendrel_attrs() to the parent's.  So in
the case where the parent's included a whole-row Var for the parent, the
child's contained a ConvertRowtypeExpr.  To cope with that, that commit
added code to the planner, such as setrefs.c, but some code paths still
assumed that the tlist for a scan (or join) rel would only include Vars
and PlaceHolderVars, which was true before that commit, causing errors:

* When creating an explicit sort node for an input path for a mergejoin
  path for a child join, prepare_sort_from_pathkeys() threw the 'could not
  find pathkey item to sort' error.
* When deparsing a relation participating in a pushed down child join as a
  subquery in contrib/postgres_fdw, get_relation_column_alias_ids() threw
  the 'unexpected expression in subquery output' error.
* When performing set_plan_references() on a local join plan generated by
  contrib/postgres_fdw for EvalPlanQual support for a pushed down child
  join, fix_join_expr() threw the 'variable not found in subplan target
  lists' error.

To fix these, two approaches have been proposed: one by Ashutosh Bapat and
one by me.  While the former keeps building the child's tlist with a
ConvertRowtypeExpr, the latter builds it with a whole-row Var for the
child not to violate the planner assumption, and tries to fix it up later,
But both approaches need more work, so refuse to generate partitionwise
join paths when whole-row Vars are involved, instead.  We don't need to
handle ConvertRowtypeExprs in the child's tlists for now, so this commit
also removes the changes to the planner.

Previously, partitionwise join computed attr_needed data for each child
separately, and built the child join's tlist using that data, which also
required an extra step for adding PlaceHolderVars to that tlist, but it
would be more efficient to build it from the parent join's tlist through
the adjust_appendrel_attrs() transformation.  So this commit builds that
list that way, and simplifies build_joinrel_tlist() and placeholder.c as
well as part of set_append_rel_size() to basically what they were before
partitionwise join went in.

Back-patch to PG11 where partitionwise join was introduced.

Report by Rajkumar Raghuwanshi.  Analysis by Ashutosh Bapat, who also
provided some of regression tests.  Patch by me, reviewed by Robert Haas.

Discussion: https://postgr.es/m/CAKcux6ktu-8tefLWtQuuZBYFaZA83vUzuRd7c1YHC-yEWyYFpg@mail.gmail.com
2018-08-31 20:34:06 +09:00
config Remove test for VA_ARGS, implied by C99. 2018-08-24 10:41:45 -07:00
contrib Disable support for partitionwise joins in problematic cases. 2018-08-31 20:34:06 +09:00
doc pg_verify_checksums: rename -d to --verbose 2018-08-30 06:35:55 -03:00
src Disable support for partitionwise joins in problematic cases. 2018-08-31 20:34:06 +09:00
.dir-locals.el Update documentation editor setup instructions 2018-07-13 21:23:41 +02:00
.gitattributes Remove contrib/tsearch2. 2017-02-13 11:06:11 -05:00
.gitignore Support for optimizing and emitting code in LLVM JIT provider. 2018-03-22 11:05:22 -07:00
aclocal.m4 Add configure infrastructure (--with-llvm) to enable LLVM support. 2018-03-20 17:26:25 -07:00
configure Remove test for VA_ARGS, implied by C99. 2018-08-24 10:41:45 -07:00
configure.in Remove test for VA_ARGS, implied by C99. 2018-08-24 10:41:45 -07:00
COPYRIGHT Update copyright for 2018 2018-01-02 23:30:12 -05:00
GNUmakefile.in Remove unwanted "garbage cleanup" logic in Makefiles. 2018-08-08 14:32:29 -04:00
HISTORY Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
Makefile Fix non-GNU makefiles for AIX make. 2017-11-30 00:57:22 -08:00
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

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
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system.  Copyright and license information can be found in the
file COPYRIGHT.  A comprehensive documentation set is included in this
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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/.