We have seen one too many reports of people trying to use 9.1 extension
files in the old-fashioned way of sourcing them in psql.  Not only does
that usually not work (due to failure to substitute for MODULE_PATHNAME
and/or @extschema@), but if it did work they'd get a collection of loose
objects not an extension.  To prevent this, insert an \echo ... \quit
line that prints a suitable error message into each extension script file,
and teach commands/extension.c to ignore lines starting with \echo.
That should not only prevent any adverse consequences of loading a script
file the wrong way, but make it crystal clear to users that they need to
do it differently now.

Tom Lane, following an idea of Andrew Dunstan's.  Back-patch into 9.1
... there is not going to be much value in this if we wait till 9.2.

Added a new option --extra-install to pg_regress to arrange installing
the respective contrib directory into the temporary installation.
This is currently not yet supported for Windows MSVC builds.

Updated the .gitignore files for contrib modules to ignore the
leftovers of a temp-install check run.

Changed the exit status of "make check" in a pgxs build (which still
does nothing) to 0 from 1.

Added "make check" in contrib to top-level "make check-world".

Using DEFAULT_COLLATION_OID in the comparePartial functions was not only
a lame hack, but outright wrong, because the compare functions for
collation-aware types were already responding to the declared index
collation.  So comparePartial would have the wrong expectation about
the index's sort order, possibly leading to missing matches for prefix
searches.

Since collation is effectively an argument, not a property of the function,
FmgrInfo is really the wrong place for it; and this becomes critical in
cases where a cached FmgrInfo is used for varying purposes that might need
different collation settings.  Fix by passing it in FunctionCallInfoData
instead.  In particular this allows a clean fix for bug #5970 (record_cmp
not working).  This requires touching a bit more code than the original
method, but nobody ever thought that collations would not be an invasive
patch...

It was never terribly consistent to use OR REPLACE (because of the lack of
comparable functionality for data types, operators, etc), and
experimentation shows that it's now positively pernicious in the extension
world.  We really want a failure to occur if there are any conflicts, else
it's unclear what the extension-ownership state of the conflicted object
ought to be.  Most of the time, CREATE EXTENSION will fail anyway because
of conflicts on other object types, but an extension defining only
functions can succeed, with bad results.

This isn't fully tested as yet, in particular I'm not sure that the
"foo--unpackaged--1.0.sql" scripts are OK.  But it's time to get some
buildfarm cycles on it.

sepgsql is not converted to an extension, mainly because it seems to
require a very nonstandard installation process.

Dimitri Fontaine and Tom Lane

This adds collation support for columns and domains, a COLLATE clause
to override it per expression, and B-tree index support.

Peter Eisentraut
reviewed by Pavel Stehule, Itagaki Takahiro, Robert Haas, Noah Misch

Also do some further work in the back branches, where quite a bit wasn't
covered by Magnus' original back-patch.

we're not going to support that anymore.

I did keep the 64-bit-CRC-with-32-bit-arithmetic code, since it has a
performance excuse to live.  It's a bit moot since that's all ifdef'd
out, of course.

Add bytea.h inclusions as needed.  Some of the contrib regression tests
need to be de-hexified, too.  Per buildfarm.

provided by Andrew.

Teodor Sigaev and Oleg Bartunov