As Tom Lane pointed out, "const Relation foo" doesn't guarantee that you
can't modify the data the "foo" pointer points to. It just means that you
can't change the pointer to point to something else within the function,
which is not very useful.

This involves two main changes from the previous behavior.  First,
when we set a bit in the visibility map, emit a new WAL record of type
XLOG_HEAP2_VISIBLE.  Replay sets the page-level PD_ALL_VISIBLE bit and
the visibility map bit.  Second, when inserting, updating, or deleting
a tuple, we can no longer get away with clearing the visibility map
bit after releasing the lock on the corresponding heap page, because
an intervening crash might leave the visibility map bit set and the
page-level bit clear.  Making this work requires a bit of interface
refactoring.

In passing, a few minor but related cleanups: change the test in
visibilitymap_set and visibilitymap_clear to throw an error if the
wrong page (or no page) is pinned, rather than silently doing nothing;
this case should never occur.  Also, remove duplicate definitions of
InvalidXLogRecPtr.

Patch by me, review by Noah Misch.

Josh Kupershmidt

This is just like serial and bigserial, except it generates an int2
column rather than int4 or int8.

Mike Pultz, reviewed by Brar Piening and Josh Kupershmidt

This allows deadlock_timeout to be reduced for transactions that are
particularly likely to be involved in a deadlock, thus detecting it
more quickly.  It is also potentially useful as a poor-man's deadlock
priority mechanism: a transaction with a high deadlock_timeout is less
likely to be chosen as the victim than one with a low
deadlock_timeout.  Since that could be used to game the system, we
make this PGC_SUSET rather than PGC_USERSET.

At some point, it might be worth thinking about a more explicit
priority mechanism, since using this is far from fool-proof.  But
let's see whether there's enough use case to justify the additional
work before we go down that route.

Noah Misch, reviewed by Shigeru Hanada

Initially, we use this only to eliminate calls to the varchar()
function in cases where the length is not being reduced and, therefore,
the function call is equivalent to a RelabelType operation.  The most
significant effect of this is that we can avoid a table rewrite when
changing a varchar(X) column to a varchar(Y) column, where Y > X.

Noah Misch, reviewed by me and Alexey Klyukin

Kevin Grittner, with additional wordsmithing by me.

Fix some grammatical issues, try to clarify a couple of proofs, make the
terminology more consistent.

A password containing a character with the high bit set was misprocessed
on machines where char is signed (which is most).  This could cause the
preceding one to three characters to fail to affect the hashed result,
thus weakening the password.  The result was also unportable, and failed
to match some other blowfish implementations such as OpenBSD's.

Since the fix changes the output for such passwords, upstream chose
to provide a compatibility hack: password salts beginning with $2x$
(instead of the usual $2a$ for blowfish) are intentionally processed
"wrong" to give the same hash as before.  Stored password hashes can
thus be modified if necessary to still match, though it'd be better
to change any affected passwords.

In passing, sync a couple other upstream changes that marginally improve
performance and/or tighten error checking.

Back-patch to all supported branches.  Since this issue is already
public, no reason not to commit the fix ASAP.

used when max_prepared_transactions=0, for the recent changes in the test
case.

already been marked as PREPARED cannot be killed. Kill the current
transaction instead.

One of the prepared_xacts regression tests actually hits this bug. I
removed the anomaly from the duplicate-gids test so that it fails in the
intended way, and added a new test to check serialization failures with
a prepared transaction.

Dan Ports

MARKED_FOR_DEATH flags into one. We still need the ROLLED_BACK flag to
mark transactions that are in the process of being rolled back. To be
precise, ROLLED_BACK now means that a transaction has already been
discounted from the count of transactions with the oldest xmin, but not
yet removed from the list of active transactions.

Dan Ports

Also be more careful about markup: use & not just &.

When recursing after an optimization in pull_up_sublinks_qual_recurse, the
available_rels value passed down must include only the relations that are
in the righthand side of the new SEMI or ANTI join; it's incorrect to pull
up a sub-select that refers to other relations, as seen in the added test
case.  Per report from BangarRaju Vadapalli.

While at it, rethink the idea of recursing below a NOT EXISTS.  That is
essentially the same situation as pulling up ANY/EXISTS sub-selects that
are in the ON clause of an outer join, and it has the same disadvantage:
we'd force the two joins to be evaluated according to the syntactic nesting
order, because the lower join will most likely not be able to commute with
the ANTI join.  That could result in having to form a rather large join
product, whereas the handling of a correlated subselect is not quite that
dumb.  So until we can handle those cases better, #ifdef NOT_USED that
case.  (I think it's okay to pull up in the EXISTS/ANY cases, because SEMI
joins aren't so inflexible about ordering.)

Back-patch to 8.4, same as for previous patch in this area.  Fortunately
that patch hadn't made it into any shipped releases yet.

Some callers were creating copies of tuple descriptors to pass to that
function, stating in code comments that it was necessary because it
modified the passed descriptor.  Code inspection reveals this not to be
true, and indeed not all callers are passing copies in the first place.
So remove the extra ones and the misleading comments about this behavior
as well.

Applied patch by Christoph Berg <cb@df7cb.de> to replace placeholder "%s" by
correct string.

The release notes may contain non-ASCII characters (for contributor
names), which lynx converts to the encoding determined by the current
locale.  The get output that is deterministic and easily readable by
everyone, we make lynx produce LATIN1 and then convert that to ASCII
with transliteration for the non-ASCII characters.

I mis-simplified the test where ANALYZE decided if it could get away
without doing anything: under the new regime, that's never allowed.  Per
bug #6068 from Jeff Janes.  Back-patch to 8.4, just like previous patch.

Since we now have a global rule in the root .gitignore,
there's no need to keep directory-specific ones as well.

Noted by Peter Eisentraut

This is a dangerous example to provide because on machines with GNU cp,
it will silently do the wrong thing and risk archive corruption.  Worse,
during the 9.0 cycle somebody "improved" the discussion by removing the
warning that used to be there about that, and instead leaving the
impression that the command would work as desired on most Unixen.
It doesn't.  Try to rectify the damage by providing an example that is safe
most everywhere, and then noting that you can try cp -i if you want but
you'd better test that.

In back-patching this to all supported branches, I also added an example
command for Windows, which wasn't provided before 9.0.

Per gripe from Tom Lane. I have tested this with VC 2008, and assume
it will work with earlier versions.

For some reason, when we (I) added table lock acquisition to pg_dump,
we didn't think about making it happen as soon as possible after the
start of the transaction.  What with subsequent additions, there was
actually quite a lot going on before we got around to that; which sort
of defeats the purpose.  Rearrange the order of calls in dumpSchema()
to close the risk window as much as we easily can.  Back-patch to all
supported branches.

The previous code went into an infinite loop after overflow.  In fact,
an overflow is not really an error; it just means that the current
value is the last one we need to return.  So, just arrange to stop
immediately when overflow is detected.

Back-patch all the way.

The code that created the init fork neglected to make sure that the
relation was open at the smgr level before attempting to invoke smgr.
This didn't happen every time; only when the relcache entry was rebuilt
along the way.

Per report from Garick Hamlin.

There's no need to add space for startupBufferPinWaitBufId, because
it's part of the PROC_HDR object for which this function already
allocates space.

This has been wrong for a while, but the only consequence is that our
shared memory allocation is increased by 4 bytes, so no back-patch.

Per Josh Kupershmidt and Tom Lane.

We had already converted most places to this style, but this patch gets the
last few that were still doing it the old way.  The main advantage is that
this exposes a greppable name for each target column, rather than having
to rely on comments (which a couple of places failed to provide anyhow).

Richard Hopkins, additional work by me to clean up update_attstats() too

gcc 4.6 complains about these because of the new option
-Wunused-but-set-variable which comes in with -Wall, so cast them to
void, which avoids the warning.

Flexible array members are a C99 feature that avoids "cheating" in the
declaration of variable-length arrays at the end of structs.  With
Autoconf support, this should be transparent for older compilers.

We start with one use in gist.h because gcc 4.6 started to raise a
warning there.  Over time, it can be expanded to other places in the
source, but they will likely need some review of sizeof and offsetof
usage.  The current change in gist.h appears to be safe in this
regard.

SSI is based on, as well as the optimizations about relative commit times
and read-only transactions. Plus a bunch of other misc fixes and
improvements.

Dan Ports

Kevin Grittner

Btree pages were recycled after VACUUM deletes all records on a
page and then a subsequent VACUUM occurs after the RecentXmin
horizon is reached. Using RecentXmin meant that we did not respond
correctly to the user controls provide to avoid Hot Standby
conflicts and so spurious conflicts could be generated in some
workload combinations. We now reuse pages only when we reach
RecentGlobalXmin, which can be much later in the presence of long
running queries and is also controlled by vacuum_defer_cleanup_age
and hot_standby_feedback.

Noah Misch and Simon Riggs

Per recommendation from Peter.  Neither choice is bulletproof, but this
is the existing style and it does help prevent unexpected environment
variable substitution.