After a patch originally submitted by Nobuhiro Iwamatsu, but corrected
(I think) to match our guidelines for safe use of asm fragments.
This should be considered untested ...

We should not try to load old statistics when re-attaching to existing
shared memory.  Per bug #4941.

Itagaki Takahiro

This is a simple test to see whether COSTS OFF will help much with getting
EXPLAIN output that's sufficiently platform-independent for use in the
regression tests.  The planner does have some freedom of choice in these
examples (plain via bitmap indexscan), so I'm not sure what will happen.

The original syntax made it difficult to add options without making them
into reserved words.  This change parenthesizes the options to avoid that
problem, and makes provision for an explicit (and perhaps non-Boolean)
value for each option.  The original syntax is still supported, but only
for the two original options ANALYZE and VERBOSE.

As a test case, add a COSTS option that can suppress the planner cost
estimates.  This may be useful for including EXPLAIN output in the regression
tests, which are otherwise unable to cope with cross-platform variations in
cost estimates.

Robert Haas

QUOTE * as a variety of FORCE QUOTE, and update psql documentation to include
the option.  (The actual psql code doesn't seem to need any changes.)

This is believed to not change the output at all, with one known exception:
"Subquery Scan foo" becomes "Subquery Scan on foo".  (We can fix that if
anyone complains, but it would be a wart, because the old code was clearly
inconsistent.)  The main intention is to remove duplicate coding and
provide a cleaner base for subsequent EXPLAIN patching.

Robert Haas

that memory allocated by starting third party DLLs doesn't end up
conflicting with it.

Hopefully this solves the long-time issue with "could not reattach
to shared memory" errors on Win32.

Patch from Tsutomu Yamada and me, based on idea from Trevor Talbot.

The fact that \dg and \du take the + option was missing in the documentation.

backpatched to 8.4

Author: Andreas Wenk <a.wenk@netzmeister-st-pauli.de>

sockopt(SO_NOSIGPIPE) or the MSG_NOSIGNAL flag to send().

We assume these features are available if (1) the symbol is defined at
compile time and (2) the kernel doesn't reject the call at runtime.
It might turn out that there are some platforms where (1) and (2) are
true and yet the signal isn't really blocked, in which case applications
would die on server crash.  If that sort of thing gets reported, then
we'll have to add additional defenses of some kind.

Jeremy Kerr

Taro Minowa (Higepon)

a physical tuple in do_tup_output().  A virtual tuple is easier to set up
and also easier for most tuple receivers to process.  Per my comment on
Robert Haas' recent patch in this code.

of individually pfree'ing pass-by-reference transition values.  This should
be at least as fast as the prior coding, and it has the major advantage of
clearing out any working data an aggregate function may have stored in or
underneath the aggcontext.  This avoids memory leakage when an aggregate
such as array_agg() is used in GROUP BY mode.  Per report from Chris Spotts.

Back-patch to 8.4.  In principle the problem could arise in prior versions,
but since they didn't have array_agg the issue seems not critical.

for the case that the semijoin was implemented within either input by
unique-ifying its RHS before we test to see if it appears to match the current
join situation.  The previous coding would select semijoin logic in situations
where we'd already unique-ified the RHS and joined it to some unrelated
relation(s), and then came to join it to the semijoin's LHS.  That still gave
the right answer as far as the semijoin itself was concerned, but would lead
to incorrectly examining only an arbitrary one of the matchable rows from the
unrelated relation(s).  The cause of this thinko was incorrect unification of
the pre-8.4 logic for IN joins and OUTER joins --- the comparable case for
outer joins can be handled after making the match test, but that's because
there is nothing like the unique-ification escape hatch for outer joins.
Per bug #4934 from Benjamin Reed.

found by "Vesa-Matti J Kari" <vmkari@cc.helsinki.fi>

so it doesn't go through BuildTupleFromCStrings.  This is more or less a
wash for current uses, but will avoid inefficiency for planned changes to
EXPLAIN.

Robert Haas

Replace redundant PLpgSQL_dstring functionality with StringInfo.
Patch by Pavel Stehule. Review by Joe Conway.

not forced out-of-line unless that is necessary to make the row fit on a
page.  Previously, they were forced out-of-line if needed to get the row
down to the default target size (1/4th page).

Kevin Grittner

In passing, make invocations of lo_xxx functions a bit more schema-safe.

Itagaki Takahiro

It appears that, for no particularly good reason, pg_listener.h deviates from
the usual convention for declaring attribute number constants.  Normally, it's

#define Anum_{catalog-name}_{column-name}  {attribute-number}

pg_listener.h, however substitutes a different string that is similar, but not
the same as, the column name.  This change fixes that.

Author: Robert Haas <robertmhaas@gmail.com>

by using a lookup table instead of a naive shift-and-count loop.  Based on
code originally posted by Sean Eron Anderson at
http://graphics.stanford.edu/%7eseander/bithacks.html.
Greg Stark did the research and benchmarking to show that this is what
we should use.  Jeremy Kerr first noticed that this is a hotspot that
could be optimized, though we ended up not using his suggestion of
platform-specific bit-searching code.

The English FAQ has been moved to the wiki, so the translated versions should
have been removed at that point as well.

The FAQ_MINGW.html should have been removed when the platform FAQs were
integrated into the documentation (or earlier).

applied to both 8.4 and 8.5

tabs in the documentation source.

reorder a semijoin into or out of the righthand side of another semijoin,
but actually it doesn't work to reorder it into or out of the righthand
side of a left or antijoin, either.  Per bug #4906 from Mathieu Fenniak.

This was sloppy thinking on my part.  This identity does work:

	( A left join B on (Pab) ) semijoin C on (Pac)
==
	( A semijoin C on (Pac) ) left join B on (Pab)

but I failed to see that that doesn't mean this does:

	( A left join B on (Pab) ) semijoin C on (Pbc)
!=
	A left join ( B semijoin C on (Pbc) ) on (Pab)

Backpatch to 8.4.X.

The original coding was not dealing specially with this file being a symlink,
with the end result that it was not installed in VPATH builds.  Oddly enough,
the clean target does know about it ...

Error messages from PL/Python now always mention the function name in the
CONTEXT: field.  This also obsoletes the few places that tried to do the
same manually.

Regression test files are updated to work with Python 2.4-2.6.  I don't have
access to older versions right now.

column names to be found in a sequence.  Per gripe from Bruce.

foo <> false, along with its previous duties of simplifying foo = true
and foo = false.  (All of these are equivalent to just foo or NOT foo
as the case may be.)  It's not clear how often this is really useful;
but it costs almost nothing to do, and it seems some people think we
should be smart about such cases.  Per recent bug report.

sequence, even when the input "tour" doesn't lead directly to such a sequence.
The stack logic that was added in 2004 only supported cases where relations
that had to be joined to each other (due to join order restrictions) were
adjacent in the tour.  However, relying on a random search to figure that out
is tremendously inefficient in large join problems, and could even fail
completely (leading to "failed to make a valid plan" errors) if
random_init_pool ran out of patience.  It seems better to make the
tour-to-plan transformation a little bit fuzzier so that every tour can form
a legal plan, even though this means that apparently different tours will
sometimes yield the same plan.

In the same vein, get rid of the logic that knew that tours (a,b,c,d,...)
are the same as tours (b,a,c,d,...), and therefore insisted the latter
are invalid.  The chance of generating two tours that differ only in
this way isn't that high, and throwing out 50% of possible tours to
avoid such duplication seems more likely to waste valuable genetic-
refinement generations than to do anything useful.

This leaves us with no cases in which geqo_eval will deem a tour invalid,
so get rid of assorted kluges that tried to deal with such cases, in
particular the undocumented assumption that DBL_MAX is an impossible
plan cost.

This is all per testing of Robert Haas' lets-remove-the-collapse-limits
patch.  That idea has crashed and burned, at least for now, but we still
got something useful out of it.

It's possible we should back-patch this change, since the "failed to make a
valid plan" error can happen in existing releases; but I'd rather not until
it has gotten more testing.

by unique-ifying the RHS and then inner-joining to some other relation,
that is not grounds for violating the RHS of some other outer join.
Noticed while regression-testing new GEQO code, which will blindly follow
any path that join_is_legal says is legal, and then complain later if that
leads to a dead end.

I'm not certain that this can result in any visible failure in 8.4: the
mistake may always be masked by the fact that subsequent attempts to join
the rest of the RHS of the other join will fail.  But I'm not certain it
can't, either, and it's definitely not operating as intended.  So back-patch.

The added regression test depends on the new no-failures-allowed logic
that I'm about to commit in GEQO, so no point back-patching that.

memory leakage in error recovery.  We were calling FreeExprContext, and
therefore invoking ExprContextCallback callbacks, in both normal and error
exits from subtransactions.  However this isn't very safe, as shown in
recent trouble report from Frank van Vugt, in which releasing a tupledesc
refcount failed.  It's also unnecessary, since the resources that callbacks
might wish to release should be cleaned up by other error recovery mechanisms
(ie the resource owners).  We only really want FreeExprContext to release
memory attached to the exprcontext in the error-exit case.  So, add a bool
parameter to FreeExprContext to tell it not to call the callbacks.

A more general solution would be to pass the isCommit bool parameter on to
the callbacks, so they could do only safe things during error exit.  But
that would make the patch significantly more invasive and possibly break
third-party code that registers ExprContextCallback callbacks.  We might want
to do that later in HEAD, but for now I'll just do what seems reasonable to
back-patch.