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Instead of having one hash table entry per relation/fork/segment, just have one per relation, and use bitmapsets to represent which specific segments need to be fsync'd. This eliminates the need to scan the whole hash table to implement FORGET_RELATION_FSYNC, which fixes the O(N^2) behavior recently demonstrated by Jeff Janes for cases involving lots of TRUNCATE or DROP TABLE operations during a single checkpoint cycle. Per an idea from Robert Haas. (FORGET_DATABASE_FSYNC still sucks, but since dropping a database is a pretty expensive operation anyway, we'll live with that.) In passing, improve the delayed-unlink code: remove the pass over the list in mdpreckpt, since it wasn't doing anything for us except supporting a useless Assert in mdpostckpt, and fix mdpostckpt so that it will absorb fsync requests every so often when clearing a large backlog of deletion requests.
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/.