It seems some people are bothered by the outdated MD5 appearing in
example code.  So replace it with more modern alternatives or by
a different example function.
Reported-by: Jon Wolski <jonwolski@gmail.com>

Add the user-callable functions sha224, sha256, sha384, sha512.  We
already had these in the C code to support SCRAM, but there was no test
coverage outside of the SCRAM tests.  Adding these as user-callable
functions allows writing some tests.  Also, we have a user-callable md5
function but no more modern alternative, which led to wide use of md5 as
a general-purpose hash function, which leads to occasional complaints
about using md5.

Also mark the existing md5 functions as leak-proof.
Reviewed-by: Michael Paquier <michael@paquier.xyz>

It's not necessary to fully initialize the executor data structures
for partitions to which no tuples are ever routed.  Consider, for
example, an INSERT statement that inserts only one row: it only cares
about the partition to which that one row is routed.  The new function
ExecInitPartitionInfo performs the initialization in question only
when a particular partition is about to receive a tuple. This includes
creating, validating, and saving a pointer to the ResultRelInfo,
setting up for speculative insertions, translating WCOs and
initializing the resulting expressions, translating returning lists
and building the appropriate projection information, and setting up a
tuple conversion map.

One thing that's not deferred is locking the child partitions; that
seems desirable but would need more thought.  Still, testing shows
that this makes single-row inserts significantly faster on a table
with many partitions without harming the bulk-insert case.

Amit Langote, reviewed by Etsuro Fujita, with a few changes by me

Discussion: http://postgr.es/m/8975331d-d961-cbdd-f862-fdd3d97dc2d0@lab.ntt.co.jp

Etsuro Fujita

Discussion: http://postgr.es/m/5A8EAF74.5010905@lab.ntt.co.jp

Commit f49842d1 introduced the
concept of a child join, but did not update this code accordingly.

Ashutosh Bapat, with cosmetic changes by me

Discussion: http://postgr.es/m/CAFjFpRf=J_KPOtw+bhZeURYkbizr8ufSaXg6gPEF6DKpgH-t6g@mail.gmail.com

Peter Geoghegan, per buildfarm member skink and Andres Freund

Discussion: http://postgr.es/m/20180221053426.gp72lw67yfpzkw7a@alap3.anarazel.de

Commit 7d8ac981 adjusted these
tests in the hope of preserving the plan shape, but I failed to
notice that the three partitions were, on my local machine, choosing
two different plan shapes.  This is probably related to the fact
that all three tables have exactly the same row count.  Try to
improve the situation by making pht1_e about half as large as
the other two.

Per Tom Lane and the buildfarm.

Discussion: http://postgr.es/m/25380.1519277713@sss.pgh.pa.us

Previously, Append didn't charge anything at all, and MergeAppend
charged only cpu_operator_cost, about half the value used here.  This
change might make MergeAppend plans slightly more likely to be chosen
than before, since this commit increases the assumed cost for Append
-- with default values -- by 0.005 per tuple but MergeAppend by only
0.0025 per tuple.  Since the comparisons required by MergeAppend are
costed separately, it's not clear why MergeAppend needs to be
otherwise more expensive than Append, so hopefully this is OK.

Prior to partition-wise join, it didn't really matter whether or not
an Append node had any cost of its own, because every plan had to use
the same number of Append or MergeAppend nodes and in the same places.
Only the relative cost of Append vs. MergeAppend made a difference.
Now, however, it is possible to avoid some of the Append nodes using a
partition-wise join, so it's worth making an effort.  Pending patches
for partition-wise aggregate care too, because an Append of Aggregate
nodes will incur the Append overhead fewer times than an Aggregate
over an Append.  Although in most cases this change will favor the use
of partition-wise techniques, it does the opposite when the join
cardinality is greater than the sum of the input cardinalities.  Since
this situation arises in an existing regression test, I [rhaas]
adjusted it to keep the overall plan shape approximately the same.

Jeevan Chalke, per a suggestion from David Rowley.  Reviewed by
Ashutosh Bapat.  Some changes by me.  The larger patch series of which
this patch is a part was also reviewed and tested by Antonin Houska,
Rajkumar Raghuwanshi, David Rowley, Dilip Kumar, Konstantin Knizhnik,
Pascal Legrand, Rafia Sabih, and me.

Discussion: http://postgr.es/m/CAKJS1f9UXdk6ZYyqbJnjFO9a9hyHKGW7B=ZRh-rxy9qxfPA5Gw@mail.gmail.com

This oversight led to data corruption in matviews, manifesting as
"could not access status of transaction" before our most recent releases,
and "found xmin from before relfrozenxid" errors since then.

The proximate cause of the problem seems to have been confusion between
the task of preserving dropped-column status and the task of preserving
frozenxid status.  Those are required for distinct sets of relkinds,
and the reasoning was entirely undocumented in the source code.  In hopes
of forestalling future errors of the same kind, try to improve the
commentary in this area.

In passing, also improve the remarkably unhelpful comments around
pg_upgrade's set_frozenxids().  That's not actually buggy AFAICS,
but good luck figuring out what it does from the old comments.

Per report from Claudio Freire.  It appears that bug #14852 from Alexey
Ermakov is an earlier report of the same issue, and there may be other
cases that we failed to identify at the time.

Patch by me based on analysis by Andres Freund.  The bug dates back
to the introduction of matviews, so back-patch to all supported branches.

Discussion: https://postgr.es/m/CAGTBQpbrY9CdRGGhyBZ9yqY4jWaGC85rUF4X+R7d-aim=mBNsw@mail.gmail.com
Discussion: https://postgr.es/m/20171013115320.28049.86457@wrigleys.postgresql.org

Commit bf6c614a broke the sepgsql test
due to a new invocation of the function access hook during grouping
equal initialization.

The new behaviour seems at least as correct as the old one, so try
adapt the tests. As I've no working sepgsql setup here, this is just
going from buildfarm results.

Author: Andres Freund
Discussion: https://postgr.es/m/20180217000337.lfsdvro3l6ccsksp@alap3.anarazel.de

Previously tts_off was, for unknown reasons, of type long. For one
that's unnecessary as tuples are restricted in length, for another
long would be a bad choice of type even if that weren't the case, as
it's not reliably wider than an int. Also HeapTupleHeader->t_len is a
uint32.

This is split off from a larger patch implementing JITed tuple
deforming. Seems like an independent improvement, as tiny as it is.

Author: Andres Freund

The previous coding here applied atoi() to strings that could represent
values too large to fit in an int.  If the overflowed value happened to
match one of the cases it was looking for, it would drop that limit
value from the output, leading to incorrect restoration of the sequence.

Avoid the unsafe behavior, and also make the logic cleaner by explicitly
calculating the default min/max values for the appropriate kind of
sequence.

Reported and patched by Alexey Bashtanov, though I whacked his patch
around a bit.  Back-patch to v10 where the faulty logic was added.

Discussion: https://postgr.es/m/cb85a9a5-946b-c7c4-9cf2-6cd6e25d7a33@imap.cc

Move the "additional restrictions" comment to ALTER TABLE ADD
CONSTRAINT instead of ADD CONSTRAINT USING INDEX; and in the latter
instead indicate that partitioned tables are unsupported

Noted by David G. Johnston
Discussion: https://postgr.es/m/CAKFQuwY4Ld7ecxL_KAmaxwt0FUu5VcPPN2L4dh+3BeYbrdBa5g@mail.gmail.com

Author: Masahiko Sawada

We were trying to use a LSN variable after releasing its containing slot
structure.

Reported by: tushar
Author: amul sul
Reviewed-by: Petr Jelinek, Masahiko Sawada
Discussion: https://postgr.es/m/94ba999c-f76a-0423-6523-b8d531dfe4c7@enterprisedb.com

An updating query that reads a CTE within an InitPlan or SubPlan could get
incorrect results if it updates rows that are concurrently being modified.
This is caused by CteScanNext supposing that nothing inside its recursive
ExecProcNode call could change which read pointer is selected in the CTE's
shared tuplestore.  While that's normally true because of scoping
considerations, it can break down if an EPQ plan tree gets built during the
call, because EvalPlanQualStart builds execution trees for all subplans
whether they're going to be used during the recheck or not.  And it seems
like a pretty shaky assumption anyway, so let's just reselect our own read
pointer here.

Per bug #14870 from Andrei Gorita.  This has been broken since CTEs were
implemented, so back-patch to all supported branches.

Discussion: https://postgr.es/m/20171024155358.1471.82377@wrigleys.postgresql.org

If we restrict unique constraints on partitioned tables so that they
must always include the partition key, then our standard approach to
unique indexes already works --- each unique key is forced to exist
within a single partition, so enforcing the unique restriction in each
index individually is enough to have it enforced globally.  Therefore we
can implement unique indexes on partitions by simply removing a few
restrictions (and adding others.)

Discussion: https://postgr.es/m/20171222212921.hi6hg6pem2w2t36z@alvherre.pgsql
Discussion: https://postgr.es/m/20171229230607.3iib6b62fn3uaf47@alvherre.pgsql
Reviewed-by: Simon Riggs, Jesper Pedersen, Peter Eisentraut, Jaime
	Casanova, Amit Langote

While this is not illegal C, project style is to put "extern" only on
declarations not definitions.

David Rowley

Discussion: https://postgr.es/m/CAKJS1f9RKLWXcMBQhvDYhmsMEo+ALuNgA-NE+AX5Uoke9DJ2Xg@mail.gmail.com

In what was doubtless a typo, commit bf6c614a introduced a duplicate
initialization of a local variable.  This made Coverity unhappy, as well
as pretty much anybody reading the code.  We don't even have a real use
for the local variable, so just remove it.

The previous code didn't compile, because static_assert() must end with
a semicolon.  To fix, wrap it in a block, similar to the C code.

Introduce a new format_type_extended, with a flags bitmask argument that
can modify the default behavior.  A few compatibility and readability
wrappers remain:
	format_type_be
	format_type_be_qualified
	format_type_with_typemod
while format_type_with_typemod_qualified, which had a single caller, is
removed.

Author: Michael Paquier, some revisions by me
Discussion: 20180213035107.GA2915@paquier.xyz

This makes it more explicit exactly what is going on, for further
proposed behavior changes.

Discussion: https://postgr.es/m/20180214212624.hm7of76flesodamf@alvherre.pgsql

The reason for doing so is that it will allow expression evaluation to
optimize based on the underlying tupledesc. In particular it will
allow to JIT tuple deforming together with the expression itself.

For that expression initialization needs to be moved after the
relevant slots are initialized - mostly unproblematic, except in the
case of nodeWorktablescan.c.

After doing so there's no need for ExecAssignResultType() and
ExecAssignResultTypeFromTL() anymore, as all former callers have been
converted to create a slot with a fixed descriptor.

When creating a slot with a fixed descriptor, tts_values/isnull can be
allocated together with the main slot, reducing allocation overhead
and increasing cache density a bit.

Author: Andres Freund
Discussion: https://postgr.es/m/20171206093717.vqdxe5icqttpxs3p@alap3.anarazel.de

This has a performance benefit on own, although not hugely so. The
primary benefit is that it will allow for to JIT tuple deforming and
comparator invocations.

Large parts of this were previously committed (773aec7a), but the
commit contained an omission around cross-type comparisons and was
thus reverted.

Author: Andres Freund
Discussion: https://postgr.es/m/20171129080934.amqqkke2zjtekd4t@alap3.anarazel.de

elog(FATAL) would end up calling PortalCleanup(), which would call
executor shutdown code, which could fail and crash, especially under
parallel query.  This was introduced by
8561e484, which did not want to mark an
active portal as failed by a normal transaction abort anymore.  But we
do need to do that for an elog(FATAL) exit.  Introduce a variable
shmem_exit_inprogress similar to the existing proc_exit_inprogress, so
we can tell whether we are in the FATAL exit scenario.
Reported-by: Andres Freund <andres@anarazel.de>

Other header files should never #include postgres.h (nor postgres_fe.h,
nor c.h), per project policy.  Also, there's no need for any backend .c
file to explicitly include elog.h or palloc.h, because postgres.h pulls
those in already.

Extracted from a larger patch by Kyotaro Horiguchi.  The rest of the
removals he suggests require more study, but these are no-brainers.

Discussion: https://postgr.es/m/20180215.200447.209320006.horiguchi.kyotaro@lab.ntt.co.jp

Discussion: https://www.postgresql.org/message-id/flat/ad24e4f4-6481-066e-e3fb-6ef4a3121882%402ndquadrant.com

This reverts commit 773aec7a.

There's an unresolved issue in the reverted commit: It only creates
one comparator function, but in for the nodeSubplan.c case we need
more (c.f. FindTupleHashEntry vs LookupTupleHashEntry calls in
nodeSubplan.c).

This isn't too difficult to fix, but it's not entirely trivial
either. The fact that the issue only causes breakage on 32bit systems
shows that the current test coverage isn't that great.  To avoid
turning half the buildfarm red till those two issues are addressed,
revert.

This has a performance benefit on own, although not hugely so. The
primary benefit is that it will allow for to JIT tuple deforming and
comparator invocations.

Author: Andres Freund
Discussion: https://postgr.es/m/20171129080934.amqqkke2zjtekd4t@alap3.anarazel.de

If a plpgsql function is declared to return a domain type, and the domain's
constraints forbid a null value, it was nonetheless possible to return
NULL, because we didn't bother to check the constraints for a null result.
I'd noticed this while fooling with domains-over-composite, but had not
gotten around to fixing it immediately.

Add a regression test script exercising this and various other domain
cases, largely borrowed from the plpython_types test.

Although this is clearly a bug fix, I'm not sure whether anyone would
thank us for changing the behavior in stable branches, so I'm inclined
not to back-patch.

One example in create_table.sgml claimed to be showing table constraint
syntax, but it was really column constraint syntax due to the omission
of a comma.  This is both wrong and confusing, so fix it in all
supported branches.

Per report from neil@postgrescompare.com.

Discussion: https://postgr.es/m/151871659877.1393.2431103178451978795@wrigleys.postgresql.org

Seems a bit silly that many (in fact all, as of today) uses of
StaticAssertExpr would need to cast it to void to avoid warnings from
pickier compilers.  Let's just do the cast right in the macro, instead.

In passing, change StaticAssertExpr to StaticAssertStmt in one
place where that seems more apropos.

Discussion: https://postgr.es/m/16161.1518715186@sss.pgh.pa.us

This is the logical conclusion of our decision to support Assert()
in both frontend and backend code: it should be possible to use that
after including just c.h.  But as things were arranged before, if
you wanted to use Assert() in code that might be compiled for either
environment, you had to include postgres.h for the backend case.
Let's simplify that.

Per buildfarm, some of whose members started throwing warnings after
commit 0c62356c added an Assert in src/port/snprintf.c.

It's possible that some other src/port files that use the stanza

#ifndef FRONTEND
#include "postgres.h"
#else
#include "postgres_fe.h"
#endif

could now be simplified to just say '#include "c.h"'.  I have not
tested for that, though, and it'd be unlikely to apply for more
than a small number of them.