The CREATE INDEX CONCURRENTLY bug can only be triggered by row updates,
not inserts, since the problem would arise from an update incorrectly
being made HOT.  Noted by Alvaro.

Backpatch-through: certain files through 9.2

That was written when we still had "crypt" authentication, and it was
referring to the fact that an older client might support "crypt"
authentication but not "md5". But we haven't supported "crypt" for years.
(As soon as we add a new authentication mechanism that doesn't work with
MD5 hashes, we'll need a similar notice again. But this text as it's worded
now is just wrong.)

Backpatch to all supported versions.

Discussion: https://www.postgresql.org/message-id/9a7263eb-0980-2072-4424-440bb2513dc7@iki.fi

Must use HH24 not HH to read a hour value exceeding 12.

This was already fixed in HEAD in commit d3cd36a1, but I didn't think
of backpatching it.

Report: https://postgr.es/m/20161229170043.10139.21416@wrigleys.postgresql.org

In addition to space accounted for by tuple_len, dead_tuple_len and
free_space, the table_len includes page overhead, the item pointers
table and padding bytes.

Backpatch to live branches.

output file naming.

Patch by Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com>

When there is both a serialization failure and a unique violation,
throw the former rather than the latter.  When initially pushed,
this was viewed as a feature to assist application framework
developers, so that they could more accurately determine when to
retry a failed transaction, but a test case presented by Ian
Jackson has shown that this patch can prevent serialization
anomalies in some cases where a unique violation is caught within a
subtransaction, the work of that subtransaction is discarded, and
no error is thrown.  That makes this a bug fix, so it is being
back-patched to all supported branches where it is not already
present (i.e., 9.2 to 9.5).

Discussion: https://postgr.es/m/1481307991-16971-1-git-send-email-ian.jackson@eu.citrix.com
Discussion: https://postgr.es/m/22607.56276.807567.924144@mariner.uk.xensource.com

If the PAGER environment variable is set but contains an empty string,
psql would pass it to "sh" which would silently exit, causing whatever
query output we were printing to vanish entirely.  This is quite
mystifying; it took a long time for us to figure out that this was the
cause of Joseph Brenner's trouble report.  Rather than allowing that
to happen, we should treat this as another way to specify "no pager".
(We could alternatively treat it as selecting the default pager, but
it seems more likely that the former is what the user meant to achieve
by setting PAGER this way.)

Nonempty, but all-white-space, PAGER values have the same behavior, and
it's pretty easy to test for that, so let's handle that case the same way.

Most other cases of faulty PAGER values will result in the shell printing
some kind of complaint to stderr, which should be enough to diagnose the
problem, so we don't need to work harder than this.  (Note that there's
been an intentional decision not to be very chatty about apparent failure
returns from the pager process, since that may happen if, eg, the user
quits the pager with control-C or some such.  I'd just as soon not start
splitting hairs about which exit codes might merit making our own report.)

libpq's old PQprint() function was already on board with ignoring empty
PAGER values, but for consistency, make it ignore all-white-space values
as well.

It's been like this a long time, so back-patch to all supported branches.

Discussion: https://postgr.es/m/CAFfgvXWLOE2novHzYjmQK8-J6TmHz42G8f3X0SORM44+stUGmw@mail.gmail.com

Per bug #14441 from Mark Pether, the documentation could be misread,
mainly because some of the examples failed to show what happens with
a multicharacter "characters to trim" string.  Also, while the text
description in most of these entries was fairly clear that the
"characters" argument is a set of characters not a substring to match,
some of them used variant wording that was a bit less clear.
trim() itself suffered from both deficiencies and was thus pretty
misinterpretable.

Also fix failure to explain which of LEADING/TRAILING/BOTH is the
default.

Discussion: https://postgr.es/m/20161130011710.6539.53657@wrigleys.postgresql.org

The documentation around the -b/--blobs option to pg_dump seemed to
imply that it might be possible to add blobs to a "schema-only" dump or
similar.  Clarify that blobs are data and therefore will only be
included in dumps where data is being included, even when -b is used to
request blobs be included.

The -b option has been around since before 9.2, so back-patch to all
supported branches.

Discussion: https://postgr.es/m/20161119173316.GA13284@tamriel.snowman.net

Create a section specifically for the syntactic rules around whole-row
variable usage, such as expansion of "foo.*".  This was previously
documented only haphazardly, with some critical info buried in
unexpected places like xfunc-sql-composite-functions.  Per repeated
questions in different mailing lists.

Discussion: <16288.1479610770@sss.pgh.pa.us>

There are assorted references to RETURNING in Part II, but nothing
that would qualify as an explanation of the feature, which seems
like an oversight considering how useful it is.  Add something.

Noted while looking for a place to point a cross-reference to ...

For a very long time, pltcl's spi_exec and spi_execp commands have had
a behavior of storing the current row number as an element of output
arrays, but this was never documented.  Fix that.

For an equally long time, pltcl_trigger_handler had a behavior of silently
ignoring ".tupno" as an output column name, evidently so that the result
of spi_exec could be used directly as a trigger result tuple.  Not sure
how useful that really is, but in any case it's bad that it would break
attempts to use ".tupno" as an actual column name.  We can fix it by not
checking for ".tupno" until after we check for a column name match.  This
comports with the effective behavior of spi_exec[p] that ".tupno" is only
magic when you don't have an actual column named that.

In passing, wordsmith the description of returning modified tuples from
a pltcl trigger.

Noted while working on Jim Nasby's patch to support composite results
from pltcl.  The inability to return trigger tuples using ".tupno" as
a column name is a bug, so back-patch to all supported branches.

Replace "Full path to ..." with "Full path name of ...".  At least one
user has misinterpreted the existing wording as meaning "Directory
containing ...".

Evidently an oversight in commit 72920557.  Back-patch to 9.2 where
privileges for types were introduced.

Report: <20160922173517.8214.88959@wrigleys.postgresql.org>

These worked as-is until around 7.0, but fail in newer versions because
there are more operators named "#".  Besides it's a bit inconsistent that
only two of the examples on this page lack type names on their constants.

Report: <20160923081530.1517.75670@wrigleys.postgresql.org>

based on patch from Takeshi Ideriha <iderihatakeshi@gmail.com>

The existing example threw an error.

From: gabrielle <gorthx@gmail.com>

Previously, we threw an error if a dynamic timezone abbreviation did not
match any abbreviation recorded in the referenced IANA time zone entry.
That seemed like a good consistency check at the time, but it turns out
that a number of the abbreviations in the IANA database are things that
Olson and crew made up out of whole cloth.  Their current policy is to
remove such names in favor of using simple numeric offsets.  Perhaps
unsurprisingly, a lot of these made-up abbreviations have varied in meaning
over time, which meant that our commit b2cbced9 and later changes made
them into dynamic abbreviations.  So with newer IANA database versions
that don't mention these abbreviations at all, we fail, as reported in bug
#14307 from Neil Anderson.  It's worse than just a few unused-in-the-wild
abbreviations not working, because the pg_timezone_abbrevs view stops
working altogether (since its underlying function tries to compute the
whole view result in one call).

We considered deleting these abbreviations from our abbreviations list, but
the problem with that is that we can't stay ahead of possible future IANA
changes.  Instead, let's leave the abbreviations list alone, and treat any
"orphaned" dynamic abbreviation as just meaning the referenced time zone.
It will behave a bit differently than it used to, in that you can't any
longer override the zone's standard vs. daylight rule by using the "wrong"
abbreviation of a pair, but that's better than failing entirely.  (Also,
this solution can be interpreted as adding a small new feature, which is
that any abbreviation a user wants can be defined as referencing a time
zone name.)

Back-patch to all supported branches, since this problem affects all
of them when using tzdata 2016f or newer.

Report: <20160902031551.15674.67337@wrigleys.postgresql.org>
Discussion: <6189.1472820913@sss.pgh.pa.us>

Previous contents of adminpack.sgml were rather far short of project norms.
Not to mention being outright wrong about the signature of pg_file_read().

Per discussion with David Johnston.

Security: CVE-2016-5423, CVE-2016-5424

The decision to reuse values of parameters from a previous connection
has been based on whether the new target is a conninfo string.  Add this
means of overriding that default.  This feature arose as one component
of a fix for security vulnerabilities in pg_dump, pg_dumpall, and
pg_upgrade, so back-patch to 9.1 (all supported versions).  In 9.3 and
later, comment paragraphs that required update had already-incorrect
claims about behavior when no connection is open; fix those problems.

Security: CVE-2016-5424

If ANALYZE found no repeated non-null entries in its sample, it set the
column's stadistinct value to -1.0, intending to indicate that the entries
are all distinct.  But what this value actually means is that the number
of distinct values is 100% of the table's rowcount, and thus it was
overestimating the number of distinct values by however many nulls there
are.  This could lead to very poor selectivity estimates, as for example
in a recent report from Andreas Joseph Krogh.  We should discount the
stadistinct value by whatever we've estimated the nulls fraction to be.
(That is what will happen if we choose to use a negative stadistinct for
a column that does have repeated entries, so this code path was just
inconsistent.)

In addition to fixing the stadistinct entries stored by several different
ANALYZE code paths, adjust the logic where get_variable_numdistinct()
forces an "all distinct" estimate on the basis of finding a relevant unique
index.  Unique indexes don't reject nulls, so there's no reason to assume
that the null fraction doesn't apply.

Back-patch to all supported branches.  Back-patching is a bit of a judgment
call, but this problem seems to affect only a few users (else we'd have
identified it long ago), and it's bad enough when it does happen that
destabilizing plan choices in a worse direction seems unlikely.

Patch by me, with documentation wording suggested by Dean Rasheed

Report: <VisenaEmail.26.df42f82acae38a58.156463942b8@tc7-visena>
Discussion: <16143.1470350371@sss.pgh.pa.us>

These were probably copied in by accident.

From: Clément Prévost <prevostclement@gmail.com>

Discussion: 20160702155517.GD18610@momjian.us

Reviewed-by: Christoph Berg

Backpatch-through: 9.1

The help message for pg_basebackup specifies that the numbers 0 through 9
are accepted as valid values of -Z option. But, previously -Z 0 was rejected
as an invalid compression level.

Per discussion, it's better to make pg_basebackup treat 0 as valid
compression level meaning no compression, like pg_dump.

Back-patch to all supported versions.

Reported-By: Jeff Janes
Reviewed-By: Amit Kapila
Discussion: CAMkU=1x+GwjSayc57v6w87ij6iRGFWt=hVfM0B64b1_bPVKRqg@mail.gmail.com

This text was added by commit ff213239, and not long thereafter obsoleted
by commit 4adc2f72 (which made the test depend on NBuffers instead); but
nobody noticed the need for an update.  Commit 9563d5b5 adds some further
dependency on maintenance_work_mem, but the existing verbiage seems to
cover that with about as much precision as we really want here.  Let's
just take it all out rather than leaving ourselves open to more errors of
omission in future.  (That solution makes this change back-patchable, too.)

Noted by Peter Geoghegan.

Discussion: <CAM3SWZRVANbj9GA9j40fAwheQCZQtSwqTN1GBTVwRrRbmSf7cg@mail.gmail.com>

Head patch was 42ec6c2d.

Reported-by: Alexander Law

Discussion: 5785FBE7.7060508@gmail.com

Backpatch-through: 9.1

The docs failed to explain that LIKE INCLUDING INDEXES would not preserve
the names of indexes and associated constraints.  Also, it wasn't mentioned
that EXCLUDE constraints would be copied by this option.  The latter
oversight seems enough of a documentation bug to justify back-patching.

In passing, do some minor copy-editing in the same area, and add an entry
for LIKE under "Compatibility", since it's not exactly a faithful
implementation of the standard's feature.

Discussion: <20160728151154.AABE64016B@smtp.hushmail.com>

The description of udt_privileges view contained an incorrect copy-pasted word.

Back-patch to 9.2 where udt_privileges view was added.

Author: Alexander Law

The SQL standard appears to specify that IS [NOT] NULL's tests of field
nullness are non-recursive, ie, we shouldn't consider that a composite
field with value ROW(NULL,NULL) is null for this purpose.
ExecEvalNullTest got this right, but eval_const_expressions did not,
leading to weird inconsistencies depending on whether the expression
was such that the planner could apply constant folding.

Also, adjust the docs to mention that IS [NOT] DISTINCT FROM NULL can be
used as a substitute test if a simple null check is wanted for a rowtype
argument.  That motivated reordering things so that IS [NOT] DISTINCT FROM
is described before IS [NOT] NULL.  In HEAD, I went a bit further and added
a table showing all the comparison-related predicates.

Per bug #14235.  Back-patch to all supported branches, since it's certainly
undesirable that constant-folding should change the semantics.

Report and patch by Andrew Gierth; assorted wordsmithing and revised
regression test cases by me.

Report: <20160708024746.1410.57282@wrigleys.postgresql.org>

From: Alexander Law <exclusion@gmail.com>

Document that index storage is dependent on the operating system's
collation library ordering, and any change in that ordering can create
invalid indexes.

Discussion: 20160617154311.GB19359@momjian.us

Backpatch-through: 9.1