8ae35e9180
The code originally just doubled the size of the tuple-pointer array so long as that would fit in allowedMem. This could result in failing to use as much as half of allowedMem, if (as is typical) the last doubling attempt didn't quite fit. Worse, we might double the array size but be unable to use most of the added slots, because there was no room left within the allowedMem limit for tuples the slots should point to. To fix, double only so long as we've used less than half of allowedMem in total. Then do one more array enlargement, but scale it based on total memory consumption so far. This will work nicely as long as the average tuple size is reasonably stable, and in any case should be better than the old method. This change will result in large sort operations consuming a larger fraction of work_mem than they typically did in the past. The release notes should mention that users may want to revisit their work_mem settings, if they'd tuned those settings based on the old behavior of sorting. Jeff Janes, reviewed by Peter Geoghegan and Robert Haas |
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| GNUmakefile.in | ||
| Makefile | ||
| README | ||
| README.git | ||
| aclocal.m4 | ||
| configure | ||
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README
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. Changes between all PostgreSQL releases are recorded in the file HISTORY. 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/.