f60d176a5e
SearchCatCacheList and ReleaseCatCacheList. Previously, we incremented and decremented the refcounts of list member tuples along with the list itself, but that's unnecessary, and very expensive when the list is big. It's cheaper to change only the list refcount. When we are considering deleting a cache entry, we have to check not only its own refcount but its parent list's ... but it's easy to arrange the code so that this check is not made in any commonly-used paths, so the cost is really nil. The bigger gain though is to refrain from DLMoveToFront'ing each individual member tuple each time the list is referenced. To keep some semblance of fair space management, lists are just marked as used or not since the last cache cleanout search, and we do a MoveToFront pass only when about to run a cleanout. In combination, these changes reduce the costs of SearchCatCacheList and ReleaseCatCacheList from about 4.5% of pgbench runtime to under 1%, according to my gprof results.
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. The JDBC, ODBC, C++, Python, and Tcl interfaces have been moved to the PostgreSQL Projects Web Site at http://gborg.postgresql.org for separate maintenance. A Perl DBI/DBD driver is available from CPAN. 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 ftp://ftp.postgresql.org/pub/. For more information look at our web site located at http://www.postgresql.org/.