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Alvaro Herrera 279628a0a7 Accelerate end-of-transaction dropping of relations
When relations are dropped, at end of transaction we need to remove the
files and clean the buffer pool of buffers containing pages of those
relations.  Previously we would scan the buffer pool once per relation
to clean up buffers.  When there are many relations to drop, the
repeated scans make this process slow; so we now instead pass a list of
relations to drop and scan the pool once, checking each buffer against
the passed list.  When the number of relations is larger than a
threshold (which as of this patch is being set to 20 relations) we sort
the array before starting, and bsearch the array; when it's smaller, we
simply scan the array linearly each time, because that's faster.  The
exact optimal threshold value depends on many factors, but the
difference is not likely to be significant enough to justify making it
user-settable.

This has been measured to be a significant win (a 15x win when dropping
100,000 relations; an extreme case, but reportedly a real one).

Author: Tomas Vondra, some tweaks by me
Reviewed by: Robert Haas, Shigeru Hanada, Andres Freund, Álvaro Herrera
2013-01-17 16:13:17 -03:00
config Improve handling of ereport(ERROR) and elog(ERROR). 2013-01-13 18:40:09 -05:00
contrib Improve handling of ereport(ERROR) and elog(ERROR). 2013-01-13 18:40:09 -05:00
doc Make pg_receivexlog and pg_basebackup -X stream work across timeline switches. 2013-01-17 20:23:00 +02:00
src Accelerate end-of-transaction dropping of relations 2013-01-17 16:13:17 -03:00
.gitignore Add gitignore for mingw/cygwin build outputs 2011-06-09 18:11:47 +02:00
aclocal.m4
configure Improve handling of ereport(ERROR) and elog(ERROR). 2013-01-13 18:40:09 -05:00
configure.in Improve handling of ereport(ERROR) and elog(ERROR). 2013-01-13 18:40:09 -05:00
COPYRIGHT Update copyrights for 2013 2013-01-01 17:15:01 -05:00
GNUmakefile.in Make init-po and update-po recursive make targets 2012-06-29 14:01:54 +03:00
Makefile Allow make check in PL directories 2011-02-15 06:52:12 +02:00
README
README.git

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/.