This commit fixes psql, pg_dump, and the information schema to be
consistent with the backend changes which I made as part of commit
be90032e, and also includes a
related documentation tweak.

Shigeru Hanada, with slight adjustment.

The code to assemble ldap_get_values_len's output into a single string
wrote the terminating null one byte past where it should.  Fix that,
and make some other cosmetic adjustments to make the code a trifle more
readable and more in line with usual Postgres coding style.

Also, free the "result" string when done with it, to avoid a permanent
memory leak.

Bug report and patch by Albe Laurenz, cosmetic adjustments by me.

Failure to distinguish these cases is the real cause behind the recent
reports of Windows builds crashing on 'infinity'::timestamp, which was
directly due to failure to establish a value of timezone_abbreviations
in postmaster child processes.  The postmaster had the desired value,
but write_one_nondefault_variable() didn't transmit it to backends.

To fix that, invent a new value PGC_S_DYNAMIC_DEFAULT, and be sure to use
that or PGC_S_ENV_VAR (as appropriate) for "default" settings that are
computed during initialization.  (We need both because there's at least
one variable that could receive a value from either source.)

This commit also fixes ProcessConfigFile's failure to restore the correct
default value for certain GUC variables if they are set in postgresql.conf
and then removed/commented out of the file.  We have to recompute and
reinstall the value for any GUC variable that could have received a value
from PGC_S_DYNAMIC_DEFAULT or PGC_S_ENV_VAR sources, and there were a
number of oversights.  (That whole thing is a crock that needs to be
redesigned, but not today.)

However, I intentionally didn't make it work "exactly right" for the cases
of timezone and log_timezone.  The exactly right behavior would involve
running select_default_timezone, which we'd have to do independently in
each postgres process, causing the whole database to become entirely
unresponsive for as much as several seconds.  That didn't seem like a good
idea, especially since the variable's removal from postgresql.conf might be
just an accidental edit.  Instead the behavior is to adopt the previously
active setting as if it were default.

Note that this patch creates an ABI break for extensions that use any of
the PGC_S_XXX constants; they'll need to be recompiled.

Use ColLabel in place of ColId, so that reserved words are accepted as if
they were not reserved.  Also, remove BCONST and XCONST, which were never
documented as allowed.  Allowing those exposes to users an implementation
detail, namely the format in which the lexer outputs such constants, that
seems unwise to expose.

No documentation change needed, since this just makes the code act more
like you'd expect from reading the CREATE TRIGGER man page.

Per complaint from Szymon Guz and subsequent discussion.

just check that it's not running and PANIC if it was, but that can rightfully
happen if recovery stops at recovery target.

Normally nel == 0 works okay because the initial value of "last" will be
less than "base"; but if "base" is zero then the calculation wraps around
and we have a very large (unsigned) value for "last", so that the loop can
be entered and we get a SIGSEGV on a bogus pointer.

This is certainly the proximate cause of the recent reports of Windows
builds crashing on 'infinity'::timestamp --- evidently, they're either not
setting an active timezonetktbl, or setting an empty one.  It's not yet
clear to me why it's only happening on Windows and not happening on any
buildfarm member.  But even if that's due to some bug elsewhere, it seems
wise for this function to not choke on the powerup values of
timezonetktbl/sztimezonetktbl.

I also changed the copy of this code in ecpglib, although I am not sure
whether it's exposed to a similar hazard.

Per report and stack trace from Richard Broersma.

shared description table for pg_database comments.

Also update comments about database name selection.

Foremost, it should go to stdout.

The recent cleanup of GUC assign hooks got rid of the kludge of using
"unknown" as a magic value for timezone and log_timezone.  But I forgot
to update the documentation to match, as noted by Martin Pitt.

Discard any collation aliases that match the built-in pg_collation entries
(ie, "default", "C", "POSIX").  Such aliases would be refused by a CREATE
COLLATION command, but since initdb is injecting them via a simple INSERT,
it has to make the corresponding check for itself.  Per Martin Pitt's
report of funny behavior in a machine that had a bogus "C.UTF-8" locale.

Also, use E'' syntax for the output of escape_quotes, as per its header
comment.

that we report the libpq connection failure string.  Per suggestion from
Robert Haas.

three-value boolean logic.

Backpatch to 9.0.X since we just got another bug report about this
today.

This doesn't work as expected because the isolationtester program requires
libpq to already be installed.  While it works when you've already installed
libpq, having to already have done "make install" defeats most of the point
of a check with a temp installation.  And there are weird corner cases if
the dynamic linker picks up an old libpq.so from system library directories.
Remove the target (or more precisely, make it print a helpful message) so
people don't expect the case to work.

by 3, but that is it OK.

Remove random system #includes in favor of using postgres_fe.h.  (The
alternative to that is letting this module grow its own configuration
testing ability...)

Also fix the "make clean" target to actually clean things up.

Per local testing.

README.links to explain xref properly.

Also report the error message when the post-pg_ctl connection fails.

Per private bug report from EnterpriseDB.

Dan Ports, per head-scratching from Simon Riggs and myself.

Also adjust some error message capitalization for consistency.

KaiGai Kohei

With some compilers such as Clang and ICC emulating GCC, using a
version string of the form "GCC $version" can be quite misleading.
Also, a great while ago, the version output from gcc --version started
including the string "gcc", so it is redundant to repeat that.  In
order to support ancient GCC versions, we now prefix the result with
"GCC " only if the version output does not start with a letter.

The SSI patch inserted a call of RegisterPredicateLockingXid into
GetNewTransactionId, which was a bad idea on a couple of grounds.  First,
it's not necessary to hold XidGenLock while manipulating that shared
memory, and doing so is bad because XidGenLock is a high-contention lock
that should be held for as short a time as possible.  (Not to mention that
it adds an entirely unnecessary deadlock hazard, since we must take
SerializableXactHashLock as well.)  Second, the specific place where it was
put was between extending CLOG and advancing nextXid, which could result in
unpleasant behavior in case of a failure there.  Pull the call out to
AssignTransactionId, which is much safer and arguably better from a
modularity standpoint too.

There is more work to do to clean up the failure-before-advancing-nextXid
issue, but that is a separate change that will need to be back-patched.
So for the moment I just want to make GetNewTransactionId look the same as
it did in prior versions.

These were labeled with precedences just to avoid attaching explicit
precedences to the productions in which they were the last terminal symbol.
Since a terminal symbol precedence marking can affect many other things
too, it seems like better practice to attach precedence labels to the
productions, and not mark the terminal symbols.

Ideally we'd also remove the precedence attached to NULL_P, but it turns
out that we are actually depending on that having a precedence higher than
POSTFIXOP, else we get a shift/reduce conflict for postfix operators in
b_expr.  (Which more or less proves my point about these markings having a
high risk of unexpected consequences.)  For the moment, move NULL_P into
the set of keywords grouped with IDENT, so that at least it will act
similarly to non-keywords; and document the interaction.