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Tom Lane 602a9ef5a7 Make LOAD of an already-loaded library into a no-op, instead of attempting
to unload and re-load the library.

The difficulty with unloading a library is that we haven't defined safe
protocols for doing so.  In particular, there's no safe mechanism for
getting out of a "hook" function pointer unless libraries are unloaded
in reverse order of loading.  And there's no mechanism at all for undefining
a custom GUC variable, so GUC would be left with a pointer to an old value
that might or might not still be valid, and very possibly wouldn't be in
the same place anymore.

While the unload and reload behavior had some usefulness in easing
development of new loadable libraries, it's of no use whatever to normal
users, so just disabling it isn't giving up that much.  Someday we might
care to expend the effort to develop safe unload protocols; but even if
we did, there'd be little certainty that every third-party loadable module
was following them, so some security restrictions would still be needed.

Back-patch to 8.2; before that, LOAD was superuser-only anyway.

Security: unprivileged users could crash backend.  CVE not assigned yet
2009-09-03 22:11:07 +00:00
config Update of install-sh, mkinstalldirs, and associated configury 2009-08-26 22:24:44 +00:00
contrib Derived files that are shipped in the distribution used to be built in the 2009-08-28 20:26:19 +00:00
doc Make LOAD of an already-loaded library into a no-op, instead of attempting 2009-09-03 22:11:07 +00:00
src Make LOAD of an already-loaded library into a no-op, instead of attempting 2009-09-03 22:11:07 +00:00
COPYRIGHT Update copyright for 2009. 2009-01-01 17:24:05 +00:00
GNUmakefile.in Be able to easily figure out the target directory of "make dist". 2009-08-14 21:37:18 +00:00
Makefile Remove remains of old depend target. 2007-01-20 17:16:17 +00:00
README Point to our download URL, rather than listing interface in the README 2008-05-06 22:02:12 +00:00
README.CVS Fix the makefiles to fail cleanly if Perl is needed but not present. This 2009-06-23 03:46:00 +00:00
aclocal.m4 Add new auto-detection of thread flags. 2004-04-23 18:15:55 +00:00
configure Update of install-sh, mkinstalldirs, and associated configury 2009-08-26 22:24:44 +00:00
configure.in Update of install-sh, mkinstalldirs, and associated configury 2009-08-26 22:24:44 +00:00

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.  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/.