We had code that supposed that some platforms might offer a nonstandard
version of getpwuid_r() with only four arguments.  However, the 5-argument
definition has been standardized at least since the Single Unix Spec v2,
which is our normal reference for what's portable across all Unix-oid
platforms.  (What's more, this wasn't the only pre-standardization version
of getpwuid_r(); my old HPUX 10.20 box has still another signature.)
So let's just get rid of the now-useless configure step.

Some users run their applications in chroot environments that lack an
/etc/passwd file.  This means that the current UID's user name and home
directory are not obtainable.  libpq used to be all right with that,
so long as the database role name to use was specified explicitly.
But commit a4c8f143 broke such cases by
causing any failure of pg_fe_getauthname() to be treated as a hard error.
In any case it did little to advance its nominal goal of causing errors
in pg_fe_getauthname() to be reported better.  So revert that and instead
put some real error-reporting code in place.  This requires changes to the
APIs of pg_fe_getauthname() and pqGetpwuid(), since the latter had
departed from the POSIX-specified API of getpwuid_r() in a way that made
it impossible to distinguish actual lookup errors from "no such user".

To allow such failures to be reported, while not failing if the caller
supplies a role name, add a second call of pg_fe_getauthname() in
connectOptions2().  This is a tad ugly, and could perhaps be avoided with
some refactoring of PQsetdbLogin(), but I'll leave that idea for later.
(Note that the complained-of misbehavior only occurs in PQsetdbLogin,
not when using the PQconnect functions, because in the latter we will
never bother to call pg_fe_getauthname() if the user gives a role name.)

In passing also clean up the Windows-side usage of GetUserName(): the
recommended buffer size is 257 bytes, the passed buffer length should
be the buffer size not buffer size less 1, and any error is reported
by GetLastError() not errno.

Per report from Christoph Berg.  Back-patch to 9.4 where the chroot
failure case was introduced.  The generally poor reporting of errors
here is of very long standing, of course, but given the lack of field
complaints about it we won't risk changing these APIs further back
(even though they're theoretically internal to libpq).

If the compiler/arch combination does not provide compiler barriers,
provide a fallback. That fallback simply consists out of a function
call into a externally defined function.  That should guarantee
compiler barrierer semantics except for compilers that do inter
translation unit/global optimization - those better provide an actual
compiler barrier.

Hopefully this fixes Tom's report of linker failures due to
pg_compiler_barrier_impl not being provided.

I'm not backpatching this commit as it builds on the new atomics
infrastructure. If we decide an equivalent fix needs to be
backpatched, I'll do so in a separate commit.

Discussion: 27746.1420930690@sss.pgh.pa.us

Per report from Tom Lane.

I failed to recognize that pg_atomic_uint64 wasn't guaranteed to be 8
byte aligned on some 32bit platforms - which it has to be on some
platforms to guarantee the desired atomicity and which we assert.

As this is all compiler specific code anyway we can just rely on
compiler specific tricks to enforce alignment.

I've been unable to find concrete documentation about the version that
introduce the sunpro alignment support, so that might need additional
guards.

I've verified that this works with gcc x86 32bit, but I don't have
access to any other 32bit environment.

Discussion: op.xpsjdkil0sbe7t@vld-kuci

Per report from Vladimir Koković.

Report by Jeff Davis

Report by Tatsuo Ishii, Coverity

Wee -> We.

Pointed out by Etsuro Fujita.

For some reason I overlooked in GETTEXT_TRIGGERS that the right argument
be read by gettext in 7fcbf6a4.  This
will drop the translation percentages for the backend all the way back
to 9.3 ...

Problem reported by Heikki.

The event trigger test for rowsecurity can cause problems for other
tests which are run in parallel with it.  Instead of running that test
in the rowsecurity set, move it to the event_trigger set, which runs
isolated from other tests.

Also reverts 7161b082, which moved rowsecurity into its own test group.
That's no longer necessary, now that the event trigger test is gone from
the rowsecurity set of tests.

Pointed out by Tom.

Noticed by Amit Kapila

I'd accidentally written the comment besides the read barrier, instead
of the full barrier, implementation.

Noticed by Oskari Saarenmaa

The new logging introduced in 35192f06 made the incorrect assumption
that scan_all vacuums would always wait for buffer pins; but they only
do so if the page actually needs to be frozen.

Fix that inaccuracy by removing the difference in log output based on
scan_all and just always remove the same message.  I chose to keep the
split log message from the original commit for now, it seems likely
that it'll be of use in the future.

Also merge the line about buffer pins in autovacuum's log output into
the existing "pages: ..." line. It seems odd to have a separate line
about pins, without the "topic: " prefix others have.

Also rename the new 'pinned_pages' variable to 'pinskipped_pages'
because it actually tracks the number of pages that could *not* be
pinned.

Discussion: 20150104005324.GC9626@awork2.anarazel.de

The previous commit introduced its report at LOG level to avoid
surprises at minor release upgrade time.  Compel users deploying the
next major release to also deploy the reported workaround.

Darwin --enable-nls builds use a substitute setlocale() that may start a
thread.  Buildfarm member orangutan experienced BackendList corruption
on account of different postmaster threads executing signal handlers
simultaneously.  Furthermore, a multithreaded postmaster risks undefined
behavior from sigprocmask() and fork().  Emit LOG messages about the
problem and its workaround.  Back-patch to 9.0 (all supported versions).

Typical server invocations already achieved that.  Invalid locale
settings in the initial postmaster environment interfered, as could
malloc() failure.  Setting "LC_MESSAGES=pt_BR.utf8 LC_ALL=invalid" in
the postmaster environment will now choose C-locale messages, not
Brazilian Portuguese messages.  Most localized programs, including all
PostgreSQL frontend executables, do likewise.  Users are unlikely to
observe changes involving locale categories other than LC_MESSAGES.
CheckMyDatabase() ensures that we successfully set LC_COLLATE and
LC_CTYPE; main() sets the remaining three categories to locale "C",
which almost cannot fail.  Back-patch to 9.0 (all supported versions).

vacuum()'s static variable handling makes it non-reentrant; an ensuing
null pointer deference crashed the backend.  Back-patch to 9.0 (all
supported versions).

Since commit ba94518a, we used XLogFileOpen to open the next segment for
writing, but if the end-of-recovery happens exactly at a segment boundary,
the new segment might not exist yet. (Before ba94518a, XLogFileOpen was
correct, because we would open the previous segment if the switch happened
at the boundary.)

Instead of trying to create it if necessary, it's simpler to not bother
opening the segment at all. XLogWrite() will open or create it soon anyway,
after writing the checkpoint or end-of-recovery record.

Reported by Andres Freund.

Previously, the xml value resulting from an xpath query would not have
namespace declarations if the namespace declarations were attached to
an ancestor element in the input xml value.  That means the output value
was not correct XML.  Fix that by running the result value through
xmlCopyNode(), which produces the correct namespace declarations.

Author: Ali Akbar <the.apaan@gmail.com>

When using a historic snapshot for logical decoding it can validly
happen that a relation that's in the relcache isn't visible to that
historic snapshot.  E.g. if a newly created relation is referenced in
the query that uses the SQL interface for logical decoding and a
sinval reset occurs.

The earlier commit that fixed the error handling for that corner case
already improves the situation as a ERROR is better than hitting an
assertion... But it's obviously not good enough.  So additionally
allow that case without an error if a historic snapshot is set up -
that won't allow an invalid entry to stay in the cache because it's a)
already marked invalid and will thus be rebuilt during the next access
b) the syscaches will be reset at the end of decoding.

There might be prettier solutions to handle this case, but all that we
could think of so far end up being much more complex than this quite
simple fix.

This fixes the assertion failures reported by the buildfarm (markhor,
tick, leech) after the introduction of new regression tests in
89fd41b3. The failure there weren't actually directly caused by
CLOBBER_CACHE_ALWAYS but the extraordinary long runtimes due to it
lead to sinval resets triggering the behaviour.

Discussion: 22459.1418656530@sss.pgh.pa.us

Backpatch to 9.4 where logical decoding was introduced.

The corner case where a relcache invalidation tried to rebuild the
entry for a referenced relation but couldn't find it in the catalog
wasn't correct.

The code tried to RelationCacheDelete/RelationDestroyRelation the
entry. That didn't work when assertions are enabled because the latter
contains an assertion ensuring the refcount is zero. It's also more
generally a bad idea, because by virtue of being referenced somebody
might actually look at the entry, which is possible if the error is
trapped and handled via a subtransaction abort.

Instead just error out, without deleting the entry. As the entry is
marked invalid, the worst that can happen is that the invalid (and at
some point unused) entry lingers in the relcache.

Discussion: 22459.1418656530@sss.pgh.pa.us

There should be no way to hit this case < 9.4 where logical decoding
introduced a bug that can hit this. But since the code for handling
the corner case is there it should do something halfway sane, so
backpatch all the the way back.  The logical decoding bug will be
handled in a separate commit.

Report by Stefan Kaltenbrunner

Backpatch certain files through 9.0

This never worked, I think.  Per report from Marc Munro.

In passing, fix funny spacing in the COMMENT ON command as a result of
excess space in the "label" string.

A oversight in 2c0a4858 causes 'could not create archive status file
"...": No such file or directory' errors in pg_receivexlog if the
target directory doesn't happen to contain a archive_status
directory. That's due to a stupidly left over 'true' constant instead
of mark_done being passed down to ProcessXLogDataMsg().

The bug is only present in the master branch, and luckily wasn't
released.

Spotted by Fujii Masao.

Report by Amit Kapila

Commit 0e5680f4 contained a thinko
mixing LOCKMODE with LockTupleMode.  This caused misbehavior in the case
where a tuple is marked with a multixact with at most a FOR SHARE lock,
and another transaction tries to acquire a FOR NO KEY EXCLUSIVE lock;
this case should block but doesn't.

Include a new isolation tester spec file to explicitely try all the
tuple lock combinations; without the fix it shows the problem:

    starting permutation: s1_begin s1_lcksvpt s1_tuplock2 s2_tuplock3 s1_commit
    step s1_begin: BEGIN;
    step s1_lcksvpt: SELECT * FROM multixact_conflict FOR KEY SHARE; SAVEPOINT foo;
    a

    1
    step s1_tuplock2: SELECT * FROM multixact_conflict FOR SHARE;
    a

    1
    step s2_tuplock3: SELECT * FROM multixact_conflict FOR NO KEY UPDATE;
    a

    1
    step s1_commit: COMMIT;

With the fixed code, step s2_tuplock3 blocks until session 1 commits,
which is the correct behavior.

All other cases behave correctly.

Backpatch to 9.3, like the commit that introduced the problem.

These calls are pretty much guaranteed not to fail unless something
has gone horribly wrong, and even in that case we'd just error out a
short time later.  But since several code checkers complain about the
missing check it seems worthwile to fix it nonetheless.

Pointed out by Coverity.

Previously the computation of the total test duration, measured in
microseconds, accidentally overflowed due to accidentally using signed
32bit arithmetic.  As the only consequence is that pg_test_timing
invocations with such, overly large, durations never finished the
practical consequences of this bug are minor.

Pointed out by Coverity.

Backpatch to 9.2 where pg_test_timing was added.

In the unlikely case of stdin (fd 0) being closed, the off-by-one
would lead to pg_xlogdump failing to open files.

Spotted by Coverity.

Backpatch to 9.3 where pg_xlogdump was introduced.

Pointed out by Coverity.

Since this is mere, and debatable, cosmetics I'm not backpatching
this.

Pointed out by Coverity.

Backpatch to all supported branches, the code has been that way for a
long while.

As every error in mark_file_as_archived() will lead to a failure of
pg_basebackup the FD leak couldn't ever lead to a real problem.  It
seems better to fix the leak anyway though, rather than silence
Coverity, as the usage of the function might get extended or copied at
some point in the future.

Pointed out by Coverity.

Backpatch to 9.2, like the relevant part of the previous patch.

WAL (and timeline history) files created by pg_basebackup did not
maintain the new base backup's archive status. That's currently not a
problem if the new node is used as a standby - but if that node is
promoted all still existing files can get archived again.  With a high
wal_keep_segment settings that can happen a significant time later -
which is quite confusing.

Change both the backend (for the -x/-X fetch case) and pg_basebackup
(for -X stream) itself to always mark WAL/timeline files included in
the base backup as .done. That's in line with walreceiver.c doing so.

The verbosity of the pg_basebackup changes show pretty clearly that it
needs some refactoring, but that'd result in not be backpatchable
changes.

Backpatch to 9.1 where pg_basebackup was introduced.

Discussion: 20141205002854.GE21964@awork2.anarazel.de

Backpatch to 9.3 where src/common was introduce, because a bugfix that
needs to be backpatched, requires the function. Earlier branches will
have to duplicate the code.

At one point in the development of this feature, it was claimed that
allowing negative values would be useful to compensate for timezone
differences between master and slave servers.  That was based on a mistaken
assumption that commit timestamps are recorded in local time; but of course
they're in UTC.  Nor is a negative apply delay likely to be a sane way of
coping with server clock skew.  However, the committed patch still treated
negative delays as doing something, and the timezone misapprehension
survived in the user documentation as well.

If recovery_min_apply_delay were a proper GUC we'd just set the minimum
allowed value to be zero; but for the moment it seems better to treat
negative settings as if they were zero.

In passing do some extra wordsmithing on the parameter's documentation,
including correcting a second misstatement that the parameter affects
processing of Restore Point records.

Issue noted by Michael Paquier, who also provided the code patch; doc
changes by me.  Back-patch to 9.4 where the feature was introduced.

The system file is always in the absolute path /etc/, not relative.

David Fetter