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Tom Lane 6c82d8d1fd Further reduce overhead for passing plpgsql variables to the executor. 
This builds on commit 21dcda2713 by keeping
a plpgsql function's shared ParamListInfo's entries for simple variables
(PLPGSQL_DTYPE_VARs) valid at all times.  That adds a few cycles to each
assignment to such variables, but saves significantly more cycles each time
they are used; so except in the pathological case of many dead stores, this
should always be a win.  Initial testing says it's good for about a 10%
speedup of simple calculations; more in large functions with many datums.

We can't use this method for row/record references unfortunately, so what
we do for those is reset those ParamListInfo slots after use; which we
can skip doing unless some of them were actually evaluated during the
previous evaluation call.  So this should frequently be a win as well,
while worst case is that it's similar cost to the previous approach.

Also, closer study suggests that the previous method of instantiating a
new ParamListInfo array per evaluation is actually probably optimal for
cursor-opening executor calls.  The reason is that whatever is visible in
the array is going to get copied into the cursor portal via copyParamList.
So if we used the function's main ParamListInfo for those calls, we'd end
up with all of its DTYPE_VAR vars getting copied, which might well include
large pass-by-reference values that the cursor actually has no need for.
To avoid a possible net degradation in cursor cases, go back to creating
and filling a private ParamListInfo in those cases (which therefore will be
exactly the same speed as before 21dcda2713).  We still get some benefit
out of this though, because this approach means that we only have to defend
against copyParamList's try-to-fetch-every-slot behavior in the case of an
unshared ParamListInfo; so plpgsql_param_fetch() can skip testing
expr->paramnos in the common case.

To ensure that the main ParamListInfo's image of a DTYPE_VAR datum is
always valid, all assignments to such variables are now funneled through
assign_simple_var().  But this makes for cleaner and shorter code anyway.
 		2015-07-05 12:57:17 -04:00
config Replace obsolete autoconf macros with their modern replacements. 2015-07-02 19:21:23 +03:00
contrib Add an optional missing_ok argument to SQL function current_setting(). 2015-07-02 16:41:07 -04:00
doc Fix bad grammar in brin.sgml. 2015-07-05 12:08:15 -04:00
src Further reduce overhead for passing plpgsql variables to the executor. 2015-07-05 12:57:17 -04:00
.dir-locals.el emacs: Set indent-tabs-mode in perl-mode 2015-04-12 23:53:23 -04:00
.gitattributes Add functions for dealing with PGP armor header lines to pgcrypto. 2014-10-01 16:03:39 +03:00
.gitignore Improve speed of make check-world 2015-04-23 08:59:52 -04:00
COPYRIGHT Update copyright for 2015 2015-01-06 11:43:47 -05:00
GNUmakefile.in Fix distclean/maintainer-clean targets to remove top-level tmp_install dir. 2015-05-13 18:48:05 -04:00
HISTORY Improve text of stub HISTORY file. 2014-02-12 18:16:17 -05:00
Makefile Allow make check in PL directories 2011-02-15 06:52:12 +02:00
README Don't generate plain-text HISTORY and src/test/regress/README anymore. 2014-02-10 20:48:04 -05:00
README.git Don't generate plain-text HISTORY and src/test/regress/README anymore. 2014-02-10 20:48:04 -05:00
aclocal.m4 Remove cvs keywords from all files. 2010-09-20 22:08:53 +02:00
configure Make numeric form of PG version number readily available in Makefiles. 2015-07-02 17:24:36 -04:00
configure.in Make numeric form of PG version number readily available in Makefiles. 2015-07-02 17:24:36 -04:00

README 

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/.