fd31cd2651
Commit a892234f830e832110f63fc0a2afce2fb21d1584 gave us enough infrastructure to avoid vacuuming pages where every tuple on the page is already frozen. So, replace the notion of a scan_all or whole-table vacuum with the less onerous notion of an "aggressive" vacuum, which will pages that are all-visible, but still skip those that are all-frozen. This should greatly reduce the cost of anti-wraparound vacuuming on large clusters where the majority of data is never touched between one cycle and the next, because we'll no longer have to read all of those pages only to find out that we don't need to do anything with them. Patch by me, reviewed by Masahiko Sawada.
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/.