The underlying C code still needs work, but this at least gets its
current regression test passing again.

in pg_largeobject_metadata).

because the old and new values are identical.

which is stored in pg_largeobject_metadata.

No backpatch to 9.0 because you can't migrate from 9.0 to 9.0 with the
same catversion (because of tablespace conflict), and a pre-9.0
migration to 9.0 has not large object permissions to migrate.

Toast tables have identical pg_class.oid and pg_class.relfilenode, but
for clarity it is good to preserve the pg_class.oid.

Update comments regarding what is preserved, and do some
variable/function renaming for clarity.

Per my recent proposal(s).  Null key datums can now be returned by
extractValue and extractQuery functions, and will be stored in the index.
Also, placeholder entries are made for indexable items that are NULL or
contain no keys according to extractValue.  This means that the index is
now always complete, having at least one entry for every indexed heap TID,
and so we can get rid of the prohibition on full-index scans.  A full-index
scan is implemented much the same way as partial-match scans were already:
we build a bitmap representing all the TIDs found in the index, and then
drive the results off that.

Also, introduce a concept of a "search mode" that can be requested by
extractQuery when the operator requires matching to empty items (this is
just as cheap as matching to a single key) or requires a full index scan
(which is not so cheap, but it sure beats failing or giving wrong answers).
The behavior remains backward compatible for opclasses that don't return
any null keys or request a non-default search mode.

Using these features, we can now make the GIN index opclass for anyarray
behave in a way that matches the actual anyarray operators for &&, <@, @>,
and = ... which it failed to do before in assorted corner cases.

This commit fixes the core GIN code and ginarrayprocs.c, updates the
documentation, and adds some simple regression test cases for the new
behaviors using the array operators.  The tsearch and contrib GIN opclass
support functions still need to be looked over and probably fixed.

Another thing I intend to fix separately is that this is pretty inefficient
for cases where more than one scan condition needs a full-index search:
we'll run duplicate GinScanEntrys, each one of which builds a large bitmap.
There is some existing logic to merge duplicate GinScanEntrys but it needs
refactoring to make it work for entries belonging to different scan keys.

Note that most of gin.h has been split out into a new file gin_private.h,
so that gin.h doesn't export anything that's not supposed to be used by GIN
opclasses or the rest of the backend.  I did quite a bit of other code
beautification work as well, mostly fixing comments and choosing more
appropriate names for things.

functions.

handling.  (metadata user ids still an open issue).

up pg_dump's calling of pg_upgrade_support functions.

servers because, like pg_largeobject, it is a system table whose
contents are not dumped by pg_dump --schema-only.

Foreign tables are a core component of SQL/MED.  This commit does
not provide a working SQL/MED infrastructure, because foreign tables
cannot yet be queried.  Support for foreign table scans will need to
be added in a future patch.  However, this patch creates the necessary
system catalog structure, syntax support, and support for ancillary
operations such as COMMENT and SECURITY LABEL.

Shigeru Hanada, heavily revised by Robert Haas

pointers, which simplifies the code.  This was not possible in 9.0 because
everything was in a single nested struct, but is possible now.

Per suggestion from Tom.

Don't insist on pg_dumpall and psql being present in the old cluster,
since they are not needed.  Do insist on pg_resetxlog being present
(in both old and new), since we need it.  Also check for pg_config,
but only in the new cluster.  Remove the useless attempt to call
pg_config in the old cluster; we don't need to know the old value of
--pkglibdir.  (In the case of a stripped-down migration installation
there might be nothing there to look at anyway, so any future change
that might reintroduce that need would have to be considered carefully.)

Per my attempts to build a minimal previous-version installation to support
pg_upgrade.

It appears that this will be faster for all but the shortest strings;
at least one some platforms, memcmp() can use word-at-a-time comparisons.

Noah Misch, somewhat pared down.

After parsing a parenthesized subexpression, we must pop all pending
ANDs and NOTs off the stack, just like the case for a simple operand.
Per bug #5793.

Also fix clones of this routine in contrib/intarray and contrib/ltree,
where input of types query_int and ltxtquery had the same problem.

Back-patch to all supported versions.

This patch replaces Guttman's generalized split method with a simple
sort-by-center-points algorithm.  Since the data is only one-dimensional
we don't really need the slow and none-too-stable Guttman method.

This is in part a bug fix, since seg has the same size_alpha versus
size_beta typo that was recently fixed in contrib/cube.  It seems
prudent to apply this rather aggressive fix only in HEAD, though.
Back branches will just get the typo fix.

Alexander Korotkov, reviewed by Yeb Havinga

documentation.  (Many were left over from the old pg_migrator naming.)

1. Don't reimplement S_ISDIR() and S_ISREG() badly.
2. Don't reimplement access() badly.

This code appears to have been copied from ancient versions of the
corresponding backend routines, and not patched to incorporate subsequent
fixes (see my commits of 2008-03-31 and 2010-01-14 respectively).
It might be a good idea to change it to just *call* those routines,
but for now I'll just transpose these fixes over.

Teodor Sigaev, with some revision by Tom

Fujii Masao

KaiGai Kohei, with a few changes by me.

Most of the functions that execute XPath queries leaked the data structures
created by libxml2.  This memory would not be recovered until end of
session, so it mounts up pretty quickly in any serious use of the feature.
Per report from Pavel Stehule, though this isn't his patch.

Back-patch to all supported branches.

except creating new connections.

This eliminates the need for inefficient implementions of this
functionality in both contrib/dblink and contrib/tablefunc, so remove
them.  The upcoming patch implementing an in-core format() function
will also require this functionality.

In passing, add some regression tests.

Alexander Korotkov

Itagaki Takahiro, with slight modifications.