Tom Lane dab52ab13d Improve ExecStoreTuple to be smarter about replacing the contents of
a TupleTableSlot: instead of calling ExecClearTuple, inline the needed
operations, so that we can avoid redundant steps.  In particular, when
the old and new tuples are both on the same disk page, avoid releasing
and re-acquiring the buffer pin --- this saves work in both the bufmgr
and ResourceOwner modules.  To make this improvement actually useful,
partially revert a change I made on 2004-04-21 that caused SeqNext
et al to call ExecClearTuple before ExecStoreTuple.  The motivation
for that, to avoid grabbing the BufMgrLock separately for releasing
the old buffer and grabbing the new one, no longer applies.  My
profiling says that this saves about 5% of the CPU time for an
all-in-memory seqscan.
2005-11-25 04:24:48 +00:00
2005-11-24 04:40:27 +00:00
2005-11-05 16:42:02 +00:00
2005-11-05 16:42:02 +00:00
2004-12-31 22:04:05 +00:00

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/.
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