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Previously, in set_append_rel_size(), we generated tlists and EC members for dummy children for possible use by partition-wise join, even if partition-wise join was disabled or the top parent was not a partitioned table, but adding such EC members causes noticeable planning speed degradation for queries with certain kinds of join quals like "(foo.x + bar.y) = constant" where foo and bar are partitioned tables in cases where there are lots of dummy children, as the EC members lists grow huge, especially for the ECs derived from such join quals, which makes the search for the parent EC members in add_child_rel_equivalences() very time-consuming. Postpone the work until such children are actually involved in a partition-wise join. Reported-by: Sanyo Capobiango Analyzed-by: Justin Pryzby and Alvaro Herrera Author: Amit Langote, with a few additional changes by me Reviewed-by: Ashutosh Bapat Backpatch-through: v11 where partition-wise join was added Discussion: https://postgr.es/m/CAO698qZnrxoZu7MEtfiJmpmUtz3AVYFVnwzR%2BpqjF%3DrmKBTgpw%40mail.gmail.com
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/.