http://archives.postgresql.org/pgsql-hackers/2007-10/msg01470.php

Throw an error for actual stop words, rather than a warning.  This fixes
problems with cache reloading causing warning messages.

Re-enable stop words in regression tests;  was disabled by Tom.

Document "?" as API change.

NOTICE.

per suggestion from Tom Lane. This fixes crash-bug reported by Stefan
Schwarzer.

a plpgsql keyword.  This avoids springing a new reserved word on plpgsql
programmers.
For consistency, handle RETURN NEXT the same way.

locale, which sorts a bit differently.  Per recent gripe from Magnus.

behavior of wchar2char/char2wchar; this should resolve bug #3730.  Avoid
excess computations of pg_mblen in t_isalpha and friends.  Const-ify
APIs where possible.

out that it's actually quite likely that a string that is an extension of
the given prefix will sort as larger than the "greater" string our previous
code created.  To provide some defense against that, do the comparisons
against a modified string instead of just the bare prefix.  We tack on
"Z", "z", "y", or "9", whichever is seen as largest in the current locale.
Testing suggests that this is sufficient at least for cases involving
ASCII data.

to validate the realm of the connecting user. By default
it's empty meaning no verification, which is the way
Kerberos authentication has traditionally worked in
PostgreSQL.

section.

those being exactly "xml".  Bug #3735 from Ben Leslie

whole table instead, to ensure that it goes away when the table is dropped.
Per bug #3723 from Sam Mason.

Backpatch as far as 7.4; AFAICT 7.3 does not have the issue, because it doesn't
have general-purpose expression indexes and so there must be at least one
column referenced by an index.

predictable manner; in particular that if you say ORDER BY output-column-ref,
it will in fact sort by that specific column even if there are multiple
syntactic matches.  An example is
	SELECT random() AS a, random() AS b FROM ... ORDER BY b, a;
While the use-case for this might be a bit debatable, it worked as expected
in earlier releases, so we should preserve the behavior for 8.3.  Per my
recent proposal.

While at it, fix convert_subquery_pathkeys() to handle RelabelType stripping
in both directions; it needs this for the same reasons make_sort_from_pathkeys
does.

to be able to discard top-level RelabelType nodes on *both* sides of the
equivalence-class-to-target-list comparison, since make_pathkey_from_sortinfo
might either add or remove a RelabelType.  Also fix the latter to do the
removal case cleanly.  Per example from Peter.

table to docs.

it seems more logical there.

make_greater_string() try harder to generate a string that's actually greater
than its input string.  Before we just assumed that making a string that was
memcmp-greater was enough, but it is easy to generate examples where this is
not so when the locale is not C.  Instead, loop until the relevant comparison
function agrees that the generated string is greater than the input.

Unfortunately this is probably not enough to guarantee that the generated
string is greater than all extensions of the input, so we cannot relax the
restriction to C locale for the LIKE/regex index optimization.  But it should
at least improve the odds of getting a useful selectivity estimate in
prefix_selectivity().  Per example from Guillaume Smet.

Backpatch to 8.1, mainly because that's what the complainant is using...

negated-match operators.  patternsel had been using the supplied operator as
though it were a positive-match operator, and thus obtaining a wrong result,
which was even more wrong after the caller subtracted it from 1.  Seems
cleanest to give patternsel an explicit "negate" argument so that it knows
what's going on.  Also install the same factorization scheme for pattern
join selectivity estimators; even though they are just stubs at the
moment, this may keep someone from making the same type of mistake when
they get filled out.  Per report from Greg Mullane.

Backpatch to 8.2 --- previous releases do not show the problem because
patternsel() doesn't actually use the operator directly.

practice also.