mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-09-28 00:11:53 +02:00
d25ea01275
If an EquivalenceClass member expression includes variables from multiple appendrels, then instead of producing one substituted expression per child relation as intended, we'd create additional child expressions for combinations of children of different appendrels. This happened because the child expressions generated while considering the first appendrel were taken as sources during substitution of the second appendrel, and so on. The extra expressions are useless, and are harmless unless there are too many of them --- but if you have several appendrels with a thousand or so members each, it gets bad fast. To fix, consider only original (non-em_is_child) EC members as candidates to be expanded. This requires the ability to substitute directly from a top parent relation's Vars to those of an indirect descendant relation, but we already have that in adjust_appendrel_attrs_multilevel(). Per bug #15847 from Feike Steenbergen. This is a longstanding misbehavior, but it's only worth worrying about when there are more appendrel children than we've historically considered wise to use. So I'm not going to take the risk of back-patching this. Discussion: https://postgr.es/m/15847-ea3734094bf8ae61@postgresql.org |
||
|---|---|---|
| config | ||
| contrib | ||
| doc | ||
| src | ||
| .dir-locals.el | ||
| .gitattributes | ||
| .gitignore | ||
| aclocal.m4 | ||
| configure | ||
| configure.in | ||
| COPYRIGHT | ||
| GNUmakefile.in | ||
| HISTORY | ||
| Makefile | ||
| README | ||
| README.git | ||
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/.