45f6240a8f
Instead of palloc'ing each HashJoinTuple individually, allocate 32kB chunks and pack the tuples densely in the chunks. This avoids the AllocChunk header overhead, and the space wasted by standard allocator's habit of rounding sizes up to the nearest power of two. This doesn't contain any planner changes, because the planner's estimate of memory usage ignores the palloc overhead. Now that the overhead is smaller, the planner's estimates are in fact more accurate. Tomas Vondra, reviewed by Robert Haas.
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/.