to reduce chattiness of logs.  Per discussion.
Simon Riggs

subtlety that this function only returns a null terminator if it's
fed input that includes one; which, in the usage here, it's not.
This probably fixes bugs reported by Thomas Haegi.

Windows-specific MultiByteToWideChar/WideCharToMultiByte calls.

missed in possible future partial-drop scenarios.  Improve comment.
Per report from Zoltan Boszormenyi.

clauselist_selectivity skip some analysis that's useless when there's only
one clause in the given list.  Actually this can win even for not-so-simple
queries, because we also apply clauselist_selectivity to sublists such as the
quals matching an index; which are likely to have only a single entry even
when the total query is quite complicated.

it is needed --- basically don't remember the previous 'search_path'
after a drop schema because it might have failed but be created later.

if the locale has the thousands separator as "".  This now matches the
to_char and psql numericlocale behavior.  (Previously this data type was
basically useless for such setups.)

where rtoffset == 0.  In that case there is no need to change Var nodes,
and since filling in unset opfuncid fields is always safe, scribbling on the
input tree to that extent is not objectionable.  This brings the cost of this
operation back down to what it was in 8.2 for simple queries.  Per
investigation of performance gripe from Guillaume Smet.

where the EquivalenceClass machinery is unable to deduce anything more from a
simple "var = const" qual clause.  There are probably some more cases where
this could be done, but this seems to take care of most of the added overhead
for simple queries.  Per gripe from Guillaume Smet.

In passing, fix a problem that was exposed by this change:
reconsider_outer_join_clause and friends were passing the wrong relids to
build_implied_join_equality, resulting in RestrictInfos with the wrong
required_relids.  This mistake was masked in typical cases since the bogus
RestrictInfos would never have escaped from the EquivalenceClass machinery,
but I think there might be corner cases involving "broken" ECs where there
would have been a visible failure even without the new optimization.  In any
case the code was certainly not operating as intended.

'ssymbol' as used in previous function.

< * Prevent long-lived temporary tables from causing frozen-Xid advancement
> * Prevent long-lived temporary tables from causing frozen-xid advancement
>
>    The problem is that autovacuum cannot vacuum them to set frozen xids;
>    only the session that created them can do that.
>
>
>

relying on stringinfo.c.  This fixes a problem reported by Marko Kreen, but I
didn't use his patch, per subsequent discussion.

ItemPointerData.

opfuncid of an OpExpr initially, considering that it has the information
at hand already.  We'll still treat opfuncid as a cache rather than a
guaranteed-valid value, but this change saves one more syscache lookup
in the normal code path.

OpExpr and related nodes.  We're going to have to set the opfuncid of
such nodes eventually (if we haven't already), so we might as well
exploit the opportunity to cache the function OID.  Buys back some
of the extra planner overhead noted by Guillaume Smet, though I still
need to fool with equivclass.c to really respond to that.

"bool" into plperl.c.  This has always been a hazard since Perl allows a
platform-specific choice to define bool as int rather than char, but
evidently this didn't happen on any platform we support ... until OS X 10.5.
Per report from Brandon Maust.

Back-patch as far as 8.0 --- a bit arbitrary, but it seems unlikely anyone
will be trying to port 7.x onto new platforms.

used.

(conflicting values).

so new thousands separator doesn't match decimal symbol.

happened to be right up against the end of memory, per report from
Matt Magoffin.  While at it, avoid useless multiple copying of string
by not depending on xmlStrncatNew.

release notes.

Adjust contrib/tsearch2 regression results to use XML tag and XML entity descriptions, as now used by core text search default parser.

Re-order some items as migration changes.

Allow tag and entity names that follow XML rules. Provide for hexadecimal
as well as decimal numeric entities. Adjust code names to coincide with
new descriptions.