psql's \s (print command history) doesn't work at all with recent libedit
versions when printing to the terminal, because libedit tries to do an
fchmod() on the target file which will fail if the target is /dev/tty.
(We'd already noted this in the context of the target being /dev/null.)
Even before that, it didn't work pleasantly, because libedit likes to
encode the command history file (to ensure successful reloading), which
renders it nigh unreadable, not to mention significantly different-looking
depending on exactly which libedit version you have.  So let's forget using
write_history() for this purpose, and instead print the data ourselves,
using logic similar to that used to iterate over the history for newline
encoding/decoding purposes.

While we're at it, insert the ability to use the pager when \s is printing
to the terminal.  This has been an acknowledged shortcoming of \s for many
years, so while you could argue it's not exactly a back-patchable bug fix
it still seems like a good improvement.  Anyone who's seriously annoyed
at this can use "\s /dev/tty" or local equivalent to get the old behavior.

Experimentation with this showed that the history iteration logic was
actually rather broken when used with libedit.  It turns out that with
libedit you have to use previous_history() not next_history() to advance
to more recent history entries.  The easiest and most robust fix for this
seems to be to make a run-time test to verify which function to call.
We had not noticed this because libedit doesn't really need the newline
encoding logic: its own encoding ensures that command entries containing
newlines are reloaded correctly (unlike libreadline).  So the effective
behavior with recent libedits was that only the oldest history entry got
newline-encoded or newline-decoded.  However, because of yet other bugs in
history_set_pos(), some old versions of libedit allowed the existing loop
logic to reach entries besides the oldest, which means there may be libedit
~/.psql_history files out there containing encoded newlines in more than
just the oldest entry.  To ensure we can reload such files, it seems
appropriate to back-patch this fix, even though that will result in some
incompatibility with older psql versions (ie, multiline history entries
written by a psql with this fix will look corrupted to a psql without it,
if its libedit is reasonably up to date).

Stepan Rutz and Tom Lane

The old claim is from my commit d06ebdb8 of
2000-07-17, but it seems to have been a plain old thinko; sum(float4) has
been distinct from sum(float8) since Berkeley days.  Noted by KaiGai Kohei.

While at it, mention the existence of sum(money), which is also of
embarrassingly ancient vintage.

Back-patch to all supported branches.

Per bug #11335 from Haruka Takatsuka

Errors detected using Topy (https://github.com/intgr/topy), all
changes verified by hand and some manual tweaks added.

Marti Raudsepp

Individual changes backpatched, where applicable, as far as 9.0.

In commit 45e02e32, we intentionally
disallowed updates on individual elements of oidvector columns.  While that
still seems like a sane idea in the abstract, we (I) forgot that citext's
"upgrade from unpackaged" script did in fact perform exactly such updates,
in order to fix the problem that citext indexes should have a collation
but would not in databases dumped or upgraded from pre-9.1 installations.

Even if we wanted to add casts to allow such updates, there's no practical
way to do so in the back branches, so the only real alternative is to make
citext's kluge even klugier.  In this patch, I cast the oidvector to text,
fix its contents with regexp_replace, and cast back to oidvector.  (Ugh!)

Since the aforementioned commit went into all active branches, we have to
fix this in all branches that contain the now-broken update script.

Per report from Eric Malm.

Some of the many error messages introduced in 458857cc missed 'FROM
unpackaged'. Also e016b724 and 45ffeb7e forgot to quote extension
version numbers.

Backpatch to 9.1, just like 458857cc which introduced the messages. Do
so because the error messages thrown when the wrong command is copy &
pasted aren't easy to understand.

Backpatch as discussed in 20140702192641.GD22738@awork2.anarazel.de
ff. as the error messages are user facing and possibly confusing.

Original commit: 6f9e39bc

Programs need execute permission on a DLL file to load it.  MSYS
"install" ignores the mode argument, and our Cygwin build statically
links libpq into programs.  That explains the lack of buildfarm trouble.
Back-patch to 9.0 (all supported versions).

The old text explained what happened if we didn't have working int64
arithmetic.  Since that case has been explicitly rejected by configure
since 8.4.3, documenting it in the 9.x branches can only produce confusion.

PG_RETURN_BOOL() should only be used in functions following the V1 SQL
function API.  This coding accidentally fails to fail since letting the
compiler coerce the Datum representation of bool back to plain bool
does give the right answer; but that doesn't make it a good idea.

Back-patch to older branches just to avoid unnecessary code divergence.

FreeBSD hasn't made any use of kern.ipc.semmap since 1.1, and newer
releases reject attempts to set it altogether; so stop recommending
that it be adjusted.  Per bug #11161.

Back-patch to all supported branches.  Before 9.3, also incorporate
commit 7a42dff4, which touches the same text and for some reason
was not back-patched at the time.

Specifically this commit updates forkname_to_number() so that the HINT
message includes "init" fork, and also adds the description of "init" fork
into pg_relation_size() document.

This is a part of the commit 2d001904
which has fixed the same oversight in master and 9.4. Back-patch to
9.1 where "init" fork was added.

The initialization fork was added in 9.1, but has not been taken into
consideration in documents of get_raw_page function in pageinspect and
storage layout. This commit fixes those oversights.

get_raw_page can read not only a table but also an index, etc. So it
should be documented that the function can read any relation. This commit
also fixes the document of pageinspect that way.

Back-patch to 9.1 where those oversights existed.

Vik Fearing, review by MauMau

The user documentation was vague and not entirely accurate about how
we treat domain inputs for ambiguous operators/functions.  Clarify
that, and add an example and some commentary.  Per a recent question
from Adam Mackler.

It's acted like this ever since we added domains, so back-patch
to all supported branches.

In commit 0ca6bda8, I rewrote the json.c
code that decided how to convert SQL data types into JSON values, so that
it no longer relied on typcategory which is a pretty untrustworthy guide
to the output format of user-defined datatypes.  However, I overlooked the
fact that CREATE DOMAIN inherits typcategory from the base type, so that
the old coding did have the desirable property of treating domains like
their base types --- but only in some cases, because not all its decisions
turned on typcategory.  The version of the patch that went into 9.4 and
up did a getBaseType() call to ensure that domains were always treated
like their base types, but I omitted that from the older branches, because
it would result in a behavioral change for domains over json or hstore;
a change that's arguably a bug fix, but nonetheless a change that users
had not asked for.  What I overlooked was that this meant that domains
over numerics and boolean were no longer treated like their base types,
and that we *did* get a complaint about, ie bug #11103 from David Grelaud.
So let's do the getBaseType() call in the older branches as well, to
restore their previous behavior in these cases.  That means 9.2 and 9.3
will now make these decisions just like 9.4.  We could probably kluge
things to still ignore the domain's base type if it's json etc, but that
seems a bit silly.

Such cases are disallowed by the SQL spec, and even if we wanted to allow
them, the semantics seem ambiguous: how should the FK columns be matched up
with the columns of a unique index?  (The matching could be significant in
the presence of opclasses with different notions of equality, so this issue
isn't just academic.)  However, our code did not previously reject such
cases, but instead would either fail to match to any unique index, or
generate a bizarre opclass-lookup error because of sloppy thinking in the
index-matching code.

David Rowley

When autovacuum is nominally off, we will still launch autovac workers
to vacuum tables that are at risk of XID wraparound.  But after we'd done
that, an autovac worker would proceed to autovacuum every table in the
targeted database, if they meet the usual thresholds for autovacuuming.
This is at best pretty unexpected; at worst it delays response to the
wraparound threat.  Fix it so that if autovacuum is nominally off, we
*only* do forced vacuums and not any other work.

Per gripe from Andrey Zhidenkov.  This has been like this all along,
so back-patch to all supported branches.

There were several oversights in recovery code where COMMIT/ABORT PREPARED
records were ignored:

* pg_last_xact_replay_timestamp() (wasn't updated for 2PC commits)
* recovery_min_apply_delay (2PC commits were applied immediately)
* recovery_target_xid (recovery would not stop if the XID used 2PC)

The first of those was reported by Sergiy Zuban in bug #11032, analyzed by
Tom Lane and Andres Freund. The bug was always there, but was masked before
commit d19bd29f, because COMMIT PREPARED
always created an extra regular transaction that was WAL-logged.

Backpatch to all supported versions (older versions didn't have all the
features and therefore didn't have all of the above bugs).

unix_socket_directories was introduced in 9.3, but the document
in older versions wrongly have mentioned it. This commit replaces
it with the correct older name unix_socket_directory.

This is applied to only 9.2 and older supported versions.

Guillaume Lelarge

findDependencyLoops() was not bright about cases where there are multiple
dependency paths between the same two dumpable objects.  In most scenarios
this did not hurt us too badly; but since the introduction of section
boundary pseudo-objects in commit a1ef01fe,
it was possible for this code to take unreasonable amounts of time (tens
of seconds on a database with a couple thousand objects), as reported in
bug #11033 from Joe Van Dyk.  Joe's particular problem scenario involved
"pg_dump -a" mode with long chains of foreign key constraints, but I think
that similar problems could arise with other situations as long as there
were enough objects.  To fix, add a flag array that lets us notice when we
arrive at the same object again while searching from a given start object.
This simple change seems to be enough to eliminate the performance problem.

Back-patch to 9.1, like the patch that introduced section boundary objects.

Spotted by Tom Lane.

Break the list of available options into an <itemizedlist> instead of
inline sentences.  This is mostly motivated by wanting to ensure that the
cross-references to the FSM and VM docs don't cross page boundaries in PDF
format; but it seems to me to read more easily this way anyway.  I took the
liberty of editorializing a bit further while at it.

Per complaint from Magnus about 9.0.18 docs not building in A4 format.
Patch all active branches so we don't get blind-sided by this particular
issue again in future.

This is consistent with the POSIX verdict that kill() shall not report
ESRCH for a zombie process.  Back-patch to 9.0 (all supported versions).
Test code from commit d7cdf6ee depends
on it, and log messages about kill() reporting "Invalid argument" will
cease to appear for this not-unexpected condition.

Commit d7cdf6ee introduced a usage
thereof.  Back-patch to 9.0, like that commit.

get_raw_page tried to validate the supplied block number against
RelationGetNumberOfBlocks(), which of course is only right when
accessing the main fork.  In most cases, the main fork is longer
than the others, so that the check was too weak (allowing a
lower-level error to be reported, but no real harm to be done).
However, very small tables could have an FSM larger than their heap,
in which case the mistake prevented access to some FSM pages.
Per report from Torsten Foertsch.

In passing, make the bad-block-number error into an ereport not elog
(since it's certainly not an internal error); and fix sloppily
maintained comment for RelationGetNumberOfBlocksInFork.

This has been wrong since we invented relation forks, so back-patch
to all supported branches.

With OpenLDAP versions 2.4.24 through 2.4.31, inclusive, PostgreSQL
backends can crash at exit.  Raise a warning during "configure" based on
the compile-time OpenLDAP version number, and test the crash scenario in
the dblink test suite.  Back-patch to 9.0 (all supported versions).

In commit 631dc390, we started to handle
simple numeric timezone offsets via the zic library instead of the old
CTimeZone/HasCTZSet kluge.  However, we overlooked the fact that the zic
code will reject UTC offsets exceeding a week (which seems a bit arbitrary,
but not because it's too tight ...).  This led to possibly setting
session_timezone to NULL, which results in crashes in most timezone-related
operations as of 9.4, and crashes in a small number of places even before
that.  So check for NULL return from pg_tzset_offset() and report an
appropriate error message.  Per bug #11014 from Duncan Gillis.

Back-patch to all supported branches, like the previous patch.
(Unfortunately, as of today that no longer includes 8.4.)

Rather remarkable that this has been wrong since 9.1 and nobody noticed.

DST law changes in Crimea, Egypt, Morocco.  New zone Antarctica/Troll
for Norwegian base in Queen Maud Land.

~/.pgpass is a sound choice everywhere, and "peer" authentication is
safe on every platform it supports.  Cease to recommend "trust"
authentication, the safety of which is deeply configuration-specific.
Back-patch to 9.0, where pg_upgrade was introduced.

If pg_regcomp failed after having invoked markst/cleanst, it would leak any
"struct subre" nodes it had created.  (We've already detected all regex
syntax errors at that point, so the only likely causes of later failure
would be query cancel or out-of-memory.)  To fix, make sure freesrnode
knows the difference between the pre-cleanst and post-cleanst cleanup
procedures.  Add some documentation of this less-than-obvious point.

Also, newlacon did the wrong thing with an out-of-memory failure from
realloc(), so that the previously allocated array would be leaked.

Both of these are pretty low-probability scenarios, but a bug is a bug,
so patch all the way back.

Per bug #10976 from Arthur O'Dwyer.

Trying to reassign objects owned by a user that had text search
dictionaries or configurations used to fail with:
ERROR:  unexpected classid 3600
or
ERROR:  unexpected classid 3602

Fix by adding cases for those object types in a switch in pg_shdepend.c.

Both REASSIGN OWNED and text search objects go back all the way to 8.1,
so backpatch to all supported branches.  In 9.3 the alter-owner code was
made generic, so the required change in recent branches is pretty
simple; however, for 9.2 and older ones we need some additional
reshuffling to enable specifying objects by OID rather than name.

Text search templates and parsers are not owned objects, so there's no
change required for them.

Per bug #9749 reported by Michal Novotný

If walsender has xmin of standby then ensure we
reset the value to 0 when we change from hot_standby_feedback=on
to hot_standby_feedback=off.

From: Josh Kupershmidt <schmiddy@gmail.com>

Adds support for autocomplete of LC_COLLATE and LC_CTYPE to
the CREATE DATABASE command in psql.

ExecEvalWholeRowVar incorrectly supposed that it could "bless" the source
TupleTableSlot just once per query.  But if the input is coming from an
Append (or, perhaps, other cases?) more than one slot might be returned
over the query run.  This led to "record type has not been registered"
errors when a composite datum was extracted from a non-blessed slot.

This bug has been there a long time; I guess it escaped notice because when
dealing with subqueries the planner tends to expand whole-row Vars into
RowExprs, which don't have the same problem.  It is possible to trigger
the problem in all active branches, though, as illustrated by the added
regression test.