Several versions of the perl that comes with the Msys DTK have been
found to have a bug that fails to recognize a ' before a multiline $ in
some circumstances. To work around the problem, use a character class
for the '. Another solution would have been to use \n instead of $, but
that would have changed the test semantics very slightly.

Commit 2834855c added a not-very-carefully-thought-out isolation test
to check a BRIN index bug fix.  The test depended on the availability
of the pageinspect contrib module, which meant it did not work in
several common testing scenarios such as "make check-world".  It's not
clear whether we want a core test depending on a contrib module like
that, but in any case, failing to deal with the possibility that the
module isn't present in the installation-under-test is not acceptable.

Remove that test pending some better solution.

There's no reason not to expose both restart_lsn and confirmed_flush
since they have rather distinct meanings. The former is the oldest WAL
still required and valid for both physical and logical slots, whereas
the latter is the location up to which a logical slot's consumer has
confirmed receiving data. Most of the time a slot will require older
WAL (i.e. restart_lsn) than the confirmed
position (i.e. confirmed_flush_lsn).

Author: Marko Tiikkaja, editorialized by me
Discussion: 559D110B.1020109@joh.to

XLogRecPtr was compared with InvalidTransactionId instead of
InvalidXLogRecPtr. As both are defined to the same value this doesn't
cause any actual problems, but it's still wrong.

Backpatch: 9.4-master, bug was introduced in 9.4

Immediately starting to stream after --create-slot is inconvenient in a
number of situations (e.g. when configuring a slot for use in
recovery.conf) and it's easy to just call pg_receivexlog twice in the
rest of the cases.

Author: Michael Paquier
Discussion: CAB7nPqQ9qEtuDiKY3OpNzHcz5iUA+DUX9FcN9K8GUkCZvG7+Ew@mail.gmail.com
Backpatch: 9.5, where the option was introduced

The allowed syntax for OVERLAPS, viz "row OVERLAPS row", is sufficiently
constrained that we don't actually need a precedence declaration for
OVERLAPS; indeed removing this declaration does not change the generated
gram.c file at all.  Let's remove it to avoid confusion about whether
OVERLAPS has precedence or not.  If we ever generalize what we allow for
OVERLAPS, we might need to put back a precedence declaration for it,
but we might want some other level than what it has today --- and leaving
the declaration there would just risk confusion about whether that would
be an incompatible change.

Likewise, remove OVERLAPS from the documentation's precedence table.

Per discussion with Noah Misch.  Back-patch to 9.5 where we hacked up some
nearby precedence decisions.

Reported by William Meitzen

commit 9043Fe390f4f0b4586cfe59cbd22314b9c3e2957 broke multibyte
regression tests because the commit removes the warning message when
temporary hash indexes is created, which has been added by commit
07af5238.

Back patched to 9.5 stable tree.

Report by Dean Rasheed

Patch by Dean Rasheed

Backpatch through 9.5

Report by Robert Haas, Andres Freund

Backpatch through 9.5

In de6fd1c8 I moved the the work around from 53f73879 into the aix
template. The previous location was removed in the former commit, and I
thought that it would be nice to emit a warning when running configure.

That didn't turn out to work because at the point the template is
included we don't know whether we're compiling a 32/64 bit binary and
it's possible to install compilers for both on a 64 bit kernel/OS.

So go back to a less ambitious approach and define
PG_FORCE_DISABLE_INLINE in port/aix.h, without emitting a warning. We
could try a more fancy approach, but it doesn't seem worth it.

This requires moving the check for PG_FORCE_DISABLE_INLINE in c.h to
after including the system headers included from therein which isn't
perfect, as it seems slightly more robust to include all system headers
in a similar environment. Oh well.

Discussion: 20150807132000.GC13310@awork2.anarazel.de

A removed check in ba3deeef made all threads but the main one busy-loop
when -P was used. All threads computed the time to the next time the
progress report should be printed, but only the main thread did so and
re-scheduled it only for the future.

Reported-By: Jesper Pedersen
Discussion: 55C4E190.3050104@redhat.com

A new test case from Andreas Seltenreich showed that we were still a bit
confused about removing PlaceHolderVars during join removal.  Specifically,
remove_rel_from_query would remove a PHV that was used only underneath
the removable join, even if the place where it's used was the join partner
relation and not the join clause being deleted.  This would lead to a
"too late to create a new PlaceHolderInfo" error later on.  We can defend
against that by checking ph_eval_at to see if the PHV could possibly be
getting used at some partner rel.

Also improve some nearby LATERAL-related logic.  I decided that the check
on ph_lateral needed to take precedence over the check on ph_needed, in
case there's a lateral reference underneath the join being considered.
(That may be impossible, but I'm not convinced of it, and it's easy enough
to defend against the case.)  Also, I realized that remove_rel_from_query's
logic for updating LateralJoinInfos is dead code, because we don't build
those at all until after join removal.

Back-patch to 9.3.  Previous versions didn't have the LATERAL issues, of
course, and they also didn't attempt to remove PlaceHolderInfos during join
removal.  (I'm starting to wonder if changing that was really such a great
idea.)

Spotted by Antonin Houska.

Some frontend code like e.g. pg_xlogdump or pg_resetxlog, has to use
backend headers. Unfortunately until now that code includes most of the
locking code. It's generally not nice to expose such low level details,
but de6fd1c8 made that a hard problem. We fall back to defining
'inline' away if the compiler doesn't support it - that can cause linker
errors like on buildfarm animal pademelon if a inline function
references backend only code.

To fix that problem separate definitions from lock.h that are required
from frontend code into lockdefs.h and use it in the relevant
places. I've only removed the minimal amount of necessary definitions
for now - it might turn out that we want more for other reasons.

To avoid such details being exposed again put some checks against being
included from frontend code into atomics.h, lock.h, lwlock.h and
s_lock.h. It's otherwise fairly easy to indirectly include these
headers.

Discussion: 20150806070902.GE12214@awork2.anarazel.de

Amit reviewed the replication origins patch and made some good
points. Address them. This fixes typos in error messages, docs and
comments and adds a missing error check (although in a
should-never-happen scenario).

Discussion: CAA4eK1JqUBVeWWKwUmBPryFaje4190ug0y-OAUHWQ6tD83V4xg@mail.gmail.com
Backpatch: 9.5, where replication origins were introduced.

Report by Andres Freund and Jeff Janes

Backpatch through 9.5

Commit 9e7e29c7 introduced an Assert that
join removal didn't reduce the eval_at set of any PlaceHolderVar to empty.
At first glance it looks like join_is_removable ensures that's true --- but
actually, the loop in join_is_removable skips PlaceHolderVars that are not
referenced above the join due to be removed.  So, if we don't want any
empty eval_at sets, the right thing to do is to delete any now-unreferenced
PlaceHolderVars from the data structure entirely.

Per fuzz testing by Andreas Seltenreich.  Back-patch to 9.3 where the
aforesaid Assert was added.

Report by Peter Geoghegan

Backpatch through 9.5

Formerly, this function would always return "true" for an appendrel child
relation, because it would think that the appendrel parent was a potential
join target for the child.  In principle that should only lead to some
inefficiency in planning, but fuzz testing by Andreas Seltenreich disclosed
that it could lead to "could not find pathkey item to sort" planner errors
in odd corner cases.  Specifically, we would think that all columns of a
child table's multicolumn index were interesting pathkeys, causing us to
generate a MergeAppend path that sorts by all the columns.  However, if any
of those columns weren't actually used above the level of the appendrel,
they would not get added to that rel's targetlist, which would result in
being unable to resolve the MergeAppend's sort keys against its targetlist
during createplan.c.

Backpatch to 9.3.  In older versions, columns of an appendrel get added
to its targetlist even if they're not mentioned above the scan level,
so that the failure doesn't occur.  It might be worth back-patching this
fix to older versions anyway, but I'll refrain for the moment.

Report by Andres Freund

Backpatch through 9.5

Report by Andres Freund

Backpatch through 9.5

Report by Dean Rasheed

Backpatch through 9.5

Further testing revealed that commit f69b4b94 was still a few
bricks shy of a load: minor tweaking of the previous test cases resulted
in the same wrong-outer-join-order problem coming back.  After study
I concluded that my previous changes in make_outerjoininfo() were just
accidentally masking the problem, and should be reverted in favor of
forcing syntactic join order whenever an upper outer join's predicate
doesn't mention a lower outer join's LHS.  This still allows the
chained-outer-joins style that is the normally optimizable case.

I also tightened things up some more in join_is_legal().  It seems to me
on review that what's really happening in the exception case where we
ignore a mismatched special join is that we're allowing the proposed join
to associate into the RHS of the outer join we're comparing it to.  As
such, we should *always* insist that the proposed join be a left join,
which eliminates a bunch of rather dubious argumentation.  The case where
we weren't enforcing that was the one that was already known buggy anyway
(it had a violatable Assert before the aforesaid commit) so it hardly
deserves a lot of deference.

Back-patch to all active branches, like the previous patch.  The added
regression test case failed in all branches back to 9.1, and I think it's
only an unrelated change in costing calculations that kept 9.0 from
choosing a broken plan.

If some, but not all, of the length word has already been read, and the
next attempt to read sees exactly the number of bytes needed to complete
the length word, or fewer, then we'll incorrectly read less than all of
the available data.

Antonin Houska

When a write transaction commits, it must clear its XID advertised via
the ProcArray, which requires that we hold ProcArrayLock in exclusive
mode in order to prevent concurrent processes running GetSnapshotData
from seeing inconsistent results.  When many processes try to commit
at once, ProcArrayLock must change hands repeatedly, with each
concurrent process trying to commit waking up to acquire the lock in
turn.  To make things more efficient, when more than one backend is
trying to commit a write transaction at the same time, have just one
of them acquire ProcArrayLock in exclusive mode and clear the XIDs of
all processes in the group.  Benchmarking reveals that this is much
more efficient at very high client counts.

Amit Kapila, heavily revised by me, with some review also from Pavan
Deolasee.

Commit e5550d5f added some new
tests for ALTER TABLE which involved table scans.  When
default_transaction_isolation = 'serializable' these acquire
relation-level SIReadLocks.  The test results didn't cope with
that.  Add SIReadLock as the minimum lock level for purposes of
these tests.

This could also be fixed by excluding this type of lock from the
my_locks view, but it would be a bug for SIReadLock to show up for
a relation which was not otherwise locked, so do it this way to
allow that sort of condition to cause a regression test failure.

There is some question whether we could avoid taking SIReadLocks
during these operations, but confirming the safety of that and
figuring out how to avoid the locks is not trivial, and would be
a separate patch.

Backpatch to 9.4 where the new tests were added.

pg_resetxlog.h contained two superfluous includes, origin.h superfluously
depended on logical.h, and pg_xlogdump's rmgrdesc.h only indirectly
included origin.h.

Backpatch: 9.5, where replication origins were introduced.

A few of the discrepancies had semantic significance, but I did not
track down the resulting user-visible bugs, if any.  Back-patch to 9.5,
where all but one discrepancy appeared.  The _equalCreateEventTrigStmt()
situation dates to 9.3 but does not affect semantics.

catversion bump due to readfuncs.c field order changes.

Commit 0ffc201a included this object
unconditionally.  Being unprepared for that, most external, single-file
modules failed to build.  This better aligns the GNU make build system
with the heuristic in the MSVC build's Project::AddDirResourceFile().
In-tree, installed modules set PGFILEDESC, so they will see no change.
Also, under PGXS, omit the nonfunctioning rule to build win32ver.rc.
Back-patch to 9.5, where the aforementioned commit first appeared.

Older versions have rmtree but not remove_tree. The one-argument forms
of these are equivalent, so replace remove_tree with rmtree. This allows
the tests to be run on oldish Msys systems.

These were causing spurious test failures.

For correctness of summarization results, it is critical that the
snapshot used during the summarization scan is able to see all tuples
that are live to all transactions -- including tuples inserted or
deleted by in-progress transactions.  Otherwise, it would be possible
for a transaction to insert a tuple, then idle for a long time while a
concurrent transaction executes summarization of the range: this would
result in the inserted value not being considered in the summary.
Previously we were trying to use a MVCC snapshot in conjunction with
adding a "placeholder" tuple in the index: the snapshot would see all
committed tuples, and the placeholder tuple would catch insertions by
any new inserters.  The hole is that prior insertions by transactions
that are still in progress by the time the MVCC snapshot was taken were
ignored.

Kevin Grittner reported this as a bogus error message during vacuum with
default transaction isolation mode set to repeatable read (because the
error report mentioned a function name not being invoked during), but
the problem is larger than that.

To fix, tweak IndexBuildHeapRangeScan to have a new mode that behaves
the way we need using SnapshotAny visibility rules.  This change
simplifies the BRIN code a bit, mainly by removing large comments that
were mistaken.  Instead, rely on the SnapshotAny semantics to provide
what it needs.  (The business about a placeholder tuple needs to remain:
that covers the case that a transaction inserts a a tuple in a page that
summarization already scanned.)

Discussion: https://www.postgresql.org/message-id/20150731175700.GX2441@postgresql.org

In passing, remove a couple of unused declarations from brin.h and
reword a comment to be proper English.  This part submitted by Kevin
Grittner.

Backpatch to 9.5, where BRIN was introduced.

Per the discussion in optimizer/README, it's unsafe to reassociate anything
into or out of the RHS of a SEMI or ANTI join.  An example from Piotr
Stefaniak showed that join_is_legal() wasn't sufficiently enforcing this
rule, so lock it down a little harder.

I couldn't find a reasonably simple example of the optimizer trying to
do this, so no new regression test.  (Piotr's example involved the random
search in GEQO accidentally trying an invalid case and triggering a sanity
check way downstream in clause selectivity estimation, which did not seem
like a sequence of events that would be useful to memorialize in a
regression test as-is.)

Back-patch to all active branches.

Per buildfarm members mandrill and hornet.

So far we have worked around the fact that some very old compilers do
not support 'inline' functions by only using inline functions
conditionally (or not at all). Since such compilers are very rare by
now, we have decided to rely on inline functions from 9.6 onwards.

To avoid breaking these old compilers inline is defined away when not
supported. That'll cause "function x defined but not used" type of
warnings, but since nobody develops on such compilers anymore that's
ok.

This change in policy will allow us to more easily employ inline
functions.

I chose to remove code previously conditional on PG_USE_INLINE as it
seemed confusing to have code dependent on a define that's always
defined.

Blacklisting of compilers, like in c53f7387, now has to be done
differently. A platform template can define PG_FORCE_DISABLE_INLINE to
force inline to be defined empty.

Discussion: 20150701161447.GB30708@awork2.anarazel.de

Previously the message erroneously printed the same LSN twice as the
assignment to the start_lsn variable was before the message. Correct
that.

Reported-By: Marko Tiikkaja
Author: Marko Tiikkaja
Backpatch: 9.5, where logical decoding was introduced