The test case that Autoconf uses to discover whether a function has
been declared doesn't work reliably with clang, because clang reports
a warning not an error if the name is a known built-in function.
On some platforms, this results in a lot of compile-time warnings about
strlcpy and related functions not having been declared.
There is a fix for this (by Noah Misch) in the upstream Autoconf sources,
but since they've not made a release in years and show no indication of
doing so anytime soon, let's just absorb their fix directly. We can
revert this when and if we update to a newer Autoconf release.
Back-patch to all supported branches.
Discussion: https://postgr.es/m/26819.1542515567@sss.pgh.pa.us
The solution arrived at in commit e74dd00f5 presumes that the compiler
has a suitable default -isysroot setting ... but further experience
shows that in many combinations of macOS version, XCode version, Xcode
command line tools version, and phase of the moon, Apple's compiler
will *not* supply a default -isysroot value.
We could potentially go back to the approach used in commit 68fc227dd,
but I don't have a lot of faith in the reliability or life expectancy of
that either. Let's just revert to the approach already shipped in 11.0,
namely specifying an -isysroot switch globally. As a partial response to
the concerns raised by Jakob Egger, adjust the contents of Makefile.global
to look like
CPPFLAGS = -isysroot $(PG_SYSROOT) ...
PG_SYSROOT = /path/to/sysroot
This allows overriding the sysroot path at build time in a relatively
painless way.
Add documentation to installation.sgml about how to use the PG_SYSROOT
option. I also took the opportunity to document how to work around
macOS's "System Integrity Protection" feature.
As before, back-patch to all supported versions.
Discussion: https://postgr.es/m/20840.1537850987@sss.pgh.pa.us
To avoid the sorts of problems complained of by Jakob Egger, it'd be
best if configure didn't emit any references to the sysroot path at all.
In the case of PL/Tcl, we can do that just by keeping our hands off the
TCL_INCLUDE_SPEC string altogether. In the case of PL/Perl, we need to
substitute -iwithsysroot for -I in the compile commands, which is easily
handled if we change to using a configure output variable that includes
the switch not only the directory name. Since PL/Tcl and PL/Python
already do it like that, this seems like good consistency cleanup anyway.
Hence, this replaces the advice given to Perl-related extensions in commit
5e2217131; instead of writing "-I$(perl_archlibexp)/CORE", they should
just write "$(perl_includespec)". (The old way continues to work, but not
on recent macOS.)
It's still the case that configure needs to be aware of the sysroot
path internally, but that's cleaner than what we had before.
As before, back-patch to all supported versions.
Discussion: https://postgr.es/m/20840.1537850987@sss.pgh.pa.us
Rethink the solution applied in commit 5e2217131 to get PL/Tcl to
build on macOS Mojave. I feared that adding -isysroot globally might
have undesirable consequences, and sure enough Jakob Egger reported
one: it complicates building extensions with a different Xcode version
than was used for the core server. (I find that a risky proposition
in general, but apparently it works most of the time, so we shouldn't
break it if we don't have to.)
We'd already adopted the solution for PL/Perl of inserting the sysroot
path directly into the -I switches used to find Perl's headers, and we
can do the same thing for PL/Tcl by changing the -iwithsysroot switch
that Apple's tclConfig.sh reports. This restricts the risks to PL/Perl
and PL/Tcl themselves and directly-dependent extensions, which is a lot
more pleasing in general than a global -isysroot switch.
Along the way, tighten the test to see if we need to inject the sysroot
path into $perl_includedir, as I'd speculated about upthread but not
gotten round to doing.
As before, back-patch to all supported versions.
Discussion: https://postgr.es/m/20840.1537850987@sss.pgh.pa.us
The method we've traditionally used, of redeclaring strerror_r() to
see if the compiler complains of inconsistent declarations, turns out
not to work reliably because some compilers only report a warning,
not an error. Amazingly, this has gone undetected for years, even
though it certainly breaks our detection of whether strerror_r
succeeded.
Let's instead test whether the compiler will take the result of
strerror_r() as a switch() argument. It's possible this won't
work universally either, but it's the best idea I could come up with
on the spur of the moment.
Back-patch of commit 751f532b9. Buildfarm results indicate that only
icc-on-Linux actually has an issue here; perhaps the lack of field
reports indicates that people don't build PG for production that way.
Discussion: https://postgr.es/m/10877.1537993279@sss.pgh.pa.us
Apple's latest rearrangements of the system-supplied headers have broken
building of PL/Perl and PL/Tcl. The only practical way to fix PL/Tcl is to
start using the "-isysroot" compiler flag to point to SDK-supplied headers,
as Apple expects. We must also start distinguishing where to find Perl's
headers from where to find its shared library; but that seems like good
cleanup anyway.
Extensions that formerly did something like -I$(perl_archlibexp)/CORE
should now do -I$(perl_includedir)/CORE instead. perl_archlibexp
is still the place to look for libperl.so, though.
If for some reason you don't like the default -isysroot setting, you can
override that by setting PG_SYSROOT in configure's arguments. I don't
currently think people would need to do so, unless maybe for cross-version
build purposes.
In addition, teach configure where to find tclConfig.sh. Our traditional
method of searching $auto_path hasn't worked for the last couple of macOS
releases, and it now seems clear that Apple's not going to change that.
The workaround of manually specifying --with-tclconfig was annoying
already, but Mojave's made it a lot more so because the sysroot path now
has to be included as well. Let's just wire the knowledge into configure
instead. To avoid breaking builds against non-default Tcl installations
(e.g. MacPorts) wherein the $auto_path method probably still works,
arrange to try the additional case only after all else has failed.
Back-patch to all supported versions, since at least the buildfarm
cares about that. The changes are set up to not do anything on macOS
releases that are old enough to not have functional sysroot trees.
As clang currently doesn't support -fexcess-precision=standard,
compiling x86-32 code with SSE2 disabled, can lead to problems with
floating point overflow checks and the like.
This issue was noticed because clang, on at least some BSDs, defaults
to i386 compatibility, whereas it defaults to pentium4 on Linux. Our
forced usage of __builtin_isinf() lead to some overflow checks not
triggering when compiling for i386, e.g. when the result of the
calculation didn't overflow in 80bit registers, but did so in 64bit.
While we could just fall back to a non-builtin isinf, it seems likely
that the use of 80bit registers leads to other problems (which is why
we force the flag for GCC already). Therefore error out when
detecting clang in that situation.
Reported-By: Victor Wagner
Analyzed-By: Andrew Gierth and Andres Freund
Author: Andres Freund
Discussion: https://postgr.es/m/20180905005130.ewk4xcs5dgyzcy45@alap3.anarazel.de
Backpatch: 9.3-, all supported versions are affected
gcc 8 has started emitting some warnings that are largely useless for
our purposes, particularly since they complain about code following
the project-standard coding convention that path names are assumed
to be shorter than MAXPGPATH. Even if we make the effort to remove
that assumption in some future release, the changes wouldn't get
back-patched. Hence, just suppress these warnings, on compilers that
have these switches.
Backpatch to all supported branches.
Discussion: https://postgr.es/m/1524563856.26306.9.camel@gunduz.org
Ancient HPUX, for one, does this. We hadn't noticed due to the lack
of regression tests that required a working strtoll.
(I was slightly tempted to remove the other historical spelling,
strto[u]q, since it seems we have no buildfarm members testing that case.
But I refrained.)
Discussion: https://postgr.es/m/151935568942.1461.14623890240535309745@wrigleys.postgresql.org
Buildfarm member dromedary is still unhappy about the recently-added
ecpg "long long" tests. The reason turns out to be that it includes
"-ansi" in its CFLAGS, and in their infinite wisdom Apple have decided
to hide the declarations of strtoll/strtoull in C89-compliant builds.
(I find it pretty curious that they hide those function declarations
when you can nonetheless declare a "long long" variable, but anyway
that is their behavior, both on dromedary's obsolete macOS version and
the newest and shiniest.) As a result, gcc assumes these functions
return "int", leading naturally to wrong results.
(Looking at dromedary's past build results, it's evident that this
problem also breaks pg_strtouint64() on 32-bit platforms; but we
evidently have no regression tests that exercise that function with
values above 32 bits.)
To fix, supply declarations for these functions when the platform
provides the functions but not the declarations, using the same type
of mechanism as we use for some other similar cases.
Discussion: https://postgr.es/m/151935568942.1461.14623890240535309745@wrigleys.postgresql.org
On Sparc64, use of __attribute__(aligned(8)) with __int128 causes faulty
code generation in gcc versions at least through 5.5.0. We can work around
that by disabling use of __int128, so teach configure to test for the bug.
This solution doesn't fix things for the case of cross-compiling with a
buggy compiler; to support that nicely, we'd need to add a manual disable
switch. Unless more such cases turn up, it doesn't seem worth the work.
Affected users could always edit pg_config.h manually.
In passing, fix some typos in the existing configure test for __int128.
They're harmless because we only compile that code not run it, but
they're still confusing for anyone looking at it closely.
This is needed in support of commit 751804998, so back-patch to 9.5
as that was.
Marina Polyakova, Victor Wagner, Tom Lane
Discussion: https://postgr.es/m/0d3a9fa264cebe1cb9966f37b7c06e86@postgrespro.ru
This is necessary for ActivePerl 5.18 onwards and for Strawberry Perl.
It is not sufficient for 32-bit builds with newer Visual Studio; these
fail with error LINK2026. Back-patch to 9.3 (all supported versions).
Reported by Victor Wagner.
Discussion: https://postgr.es/m/20160326154321.7754ab8f@wagner.wagner.home
Our initial work with int128 neglected alignment considerations, an
oversight that came back to bite us in bug #14897 from Vincent Lachenal.
It is unsurprising that int128 might have a 16-byte alignment requirement;
what's slightly more surprising is that even notoriously lax Intel chips
sometimes enforce that.
Raising MAXALIGN seems out of the question: the costs in wasted disk and
memory space would be significant, and there would also be an on-disk
compatibility break. Nor does it seem very practical to try to allow some
data structures to have more-than-MAXALIGN alignment requirement, as we'd
have to push knowledge of that throughout various code that copies data
structures around.
The only way out of the box is to make type int128 conform to the system's
alignment assumptions. Fortunately, gcc supports that via its
__attribute__(aligned()) pragma; and since we don't currently support
int128 on non-gcc-workalike compilers, we shouldn't be losing any platform
support this way.
Although we could have just done pg_attribute_aligned(MAXIMUM_ALIGNOF) and
called it a day, I did a little bit of extra work to make the code more
portable than that: it will also support int128 on compilers without
__attribute__(aligned()), if the native alignment of their 128-bit-int
type is no more than that of int64.
Add a regression test case that exercises the one known instance of the
problem, in parallel aggregation over a bigint column.
Back-patch of commit 751804998. The code known to be affected only exists
in 9.6 and later, but we do have some stuff using int128 in 9.5, so patch
back to 9.5.
Discussion: https://postgr.es/m/20171110185747.31519.28038@wrigleys.postgresql.org
Upon further review, our Bonjour code doesn't actually work with the
Avahi not-too-compatible compatibility library. While you can get it
to work on non-macOS platforms if you link to Apple's own mDNSResponder
code, there don't seem to be many people who care about that. Leaving in
the AC_SEARCH_LIBS call seems more likely to encourage people to build
broken configurations than to do anything very useful.
Hence, remove the AC_SEARCH_LIBS call and put in a warning comment instead.
Discussion: https://postgr.es/m/2D8331C5-D64F-44C1-8717-63EDC6EAF7EB@brightforge.com
On macOS the relevant functions require no special library, but elsewhere
we need to pull in libdns_sd.
Back-patch to supported branches. No docs change since the docs do not
suggest that this is a Mac-only feature.
Luke Lonergan
Discussion: https://postgr.es/m/2D8331C5-D64F-44C1-8717-63EDC6EAF7EB@brightforge.com
configure computed PG_VERSION_NUM incorrectly. (Coulda sworn I tested
that logic back when, but it had an obvious thinko.)
pg_upgrade had not been taught about the new dispensation with just
one part in the major version number.
Both things accidentally failed to fail with 10.0, but with 10.1 we
got the wrong results.
Per buildfarm.
On Linux, shared memory segments created with shm_open() are backed by
swap files created in tmpfs. If the swap file needs to be extended,
but there's no tmpfs space left, you get a very unfriendly SIGBUS trap.
To avoid this, force allocation of the full request size when we create
the segment. This adds a few cycles, but none that we wouldn't expend
later anyway, assuming the request isn't hugely bigger than the actual
need.
Make this code #ifdef __linux__, because (a) there's not currently a
reason to think the same problem exists on other platforms, and (b)
applying posix_fallocate() to an FD created by shm_open() isn't very
portable anyway.
Back-patch to 9.4 where the DSM code came in.
Thomas Munro, per a bug report from Amul Sul
Discussion: https://postgr.es/m/1002664500.12301802.1471008223422.JavaMail.yahoo@mail.yahoo.com
Instead of using a cast to force the constant to be the right width,
assume we can plaster on an L, UL, LL, or ULL suffix as appropriate.
The old approach to this is very hoary, dating from before we were
willing to require compilers to have working int64 types.
This fix makes the PG_INT64_MIN, PG_INT64_MAX, and PG_UINT64_MAX
constants safe to use in preprocessor conditions, where a cast
doesn't work. Other symbolic constants that might be defined using
[U]INT64CONST are likewise safer than before.
Also fix the SIZE_MAX macro to be similarly safe, if we are forced
to provide a definition for that. The test added in commit 2e70d6b5e
happens to do what we want even with the hack "(size_t) -1" definition,
but we could easily get burnt on other tests in future.
Back-patch to all supported branches, like the previous commits.
Discussion: https://postgr.es/m/15883.1504278595@sss.pgh.pa.us
Commit 3c163a7fc's original choice to ignore all #define symbols whose
names begin with underscore turns out to be too simplistic. On Windows,
some Perl installations are built with -D_USE_32BIT_TIME_T, and we must
absorb that or we get the wrong result for sizeof(PerlInterpreter).
This effectively re-reverts commit ef58b87df, which injected that symbol
in a hacky way, making it apply to all of Postgres not just PL/Perl.
More significantly, it did so on *all* 32-bit Windows builds, even when
the Perl build to be used did not select this option; so that it fails
to work properly with some newer Perl builds.
By making this change, we would be introducing an ABI break in 32-bit
Windows builds; but fortunately we have not used type time_t in any
exported Postgres APIs in a long time. So it should be OK, both for
PL/Perl itself and for third-party extensions, if an extension library
is built with a different _USE_32BIT_TIME_T setting than the core code.
Patch by me, based on research by Ashutosh Sharma and Robert Haas.
Back-patch to all supported branches, as commit 3c163a7fc was.
Discussion: https://postgr.es/m/CANFyU97OVQ3+Mzfmt3MhuUm5NwPU=-FtbNH5Eb7nZL9ua8=rcA@mail.gmail.com
Various bugs can cause crashes, so don't use that function before ICU
53. It will fall back to the code path used for other encodings.
Since we now tie the function availability to an ICU version, we don't
need the configure test anymore. That also resolves the issue that the
test result was previously hardcoded for Windows.
researched by Daniel Verite <daniel@manitou-mail.org>, Peter Geoghegan
<pg@bowt.ie>, Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/f1438ec6-22aa-4029-9a3b-26f79d330e72%40manitou-mail.org
The check for IPC::Run we added in commit c254970ad is useful in simple
cases, but there are real use-cases where "prove" is coming from a
different Perl installation than the "perl" we want to use to build.
In such cases asking whether "perl" knows about IPC::Run is irrelevant
and can cause an unnecessary configure failure. Hence, if user has
specified a value for PROVE, skip the IPC::Run check. Per discussion
with Andrew Dunstan.
Discussion: https://postgr.es/m/E1dcE5n-0005Sk-UE@gemulon.postgresql.org
Without ICU's header files, "configure --with-icu" would succeed anyway,
at least when using the non-pkgconfig-based setup. Then you got a bunch of
ugly failures at build. Add an explicit header check to tighten that up.
Peter Eisentraut noted that commit 40b9f1921 had broken a configure
behavior that some people might rely on: AC_CHECK_PROGS(FOO,...) will
allow the search to be overridden by specifying a value for FOO on
configure's command line or in its environment, but AC_PATH_PROGS(FOO,...)
accepts such an override only if it's an absolute path. We had worked
around that behavior for some, but not all, of the pre-existing uses
of AC_PATH_PROGS by just skipping the macro altogether when FOO is
already set. Let's standardize on that workaround for all uses of
AC_PATH_PROGS, new and pre-existing, by wrapping AC_PATH_PROGS in a
new macro PGAC_PATH_PROGS. While at it, fix a deficiency of the old
workaround code by making sure we report the setting to configure's log.
Eventually I'd like to improve PGAC_PATH_PROGS so that it converts
non-absolute override inputs to absolute form, eg "PYTHON=python3"
becomes, say, PYTHON = /usr/bin/python3. But that will take some
nontrivial coding so it doesn't seem like a thing to do in late beta.
Discussion: https://postgr.es/m/90a92a7d-938e-507a-3bd7-ecd2b4004689@2ndquadrant.com
Previously we had a mix of uses of AC_CHECK_PROG[S] and AC_PATH_PROG[S].
The only difference between those macros is that the latter emits the
full path to the program it finds, eg "/usr/bin/prove", whereas the
former emits just "prove". Let's standardize on always emitting the
full path; this is better for documentation of the build, and it might
prevent some types of failures if later build steps are done with
a different PATH setting.
I did not touch the AC_CHECK_PROG[S] calls in ax_pthread.m4 and
ax_prog_perl_modules.m4. There seems no need to make those diverge from
upstream, since we do not record the programs sought by the former, while
the latter's call to AC_CHECK_PROG(PERL,...) will never be reached.
Discussion: https://postgr.es/m/25937.1501433410@sss.pgh.pa.us
The Perl documentation is very clear that stuff calling libperl should
be built with the compiler switches shown by Perl's $Config{ccflags}.
We'd been ignoring that up to now, and mostly getting away with it,
but recent Perl versions contain ABI compatibility cross-checks that
fail on some builds because of this omission. In particular the
sizeof(PerlInterpreter) can come out different due to some fields being
added or removed; which means we have a live ABI hazard that we'd better
fix rather than continuing to sweep it under the rug.
However, it still seems like a bad idea to just absorb $Config{ccflags}
verbatim. In some environments Perl was built with a different compiler
that doesn't even use the same switch syntax. -D switch syntax is pretty
universal though, and absorbing Perl's -D switches really ought to be
enough to fix the problem.
Furthermore, Perl likes to inject stuff like -D_LARGEFILE_SOURCE and
-D_FILE_OFFSET_BITS=64 into $Config{ccflags}, which affect libc ABIs on
platforms where they're relevant. Adopting those seems dangerous too.
It's unclear whether a build wherein Perl and Postgres have different ideas
of sizeof(off_t) etc would work, or whether anyone would care about making
it work. But it's dead certain that having different stdio ABIs in
core Postgres and PL/Perl will not work; we've seen that movie before.
Therefore, let's also ignore -D switches for symbols beginning with
underscore. The symbols that we actually need to import should be the ones
mentioned in perl.h's PL_bincompat_options stanza, and none of those start
with underscore, so this seems likely to work. (If it turns out not to
work everywhere, we could consider intersecting the symbols mentioned in
PL_bincompat_options with the -D switches. But that will be much more
complicated, so let's try this way first.)
This will need to be back-patched, but first let's see what the
buildfarm makes of it.
Ashutosh Sharma, some adjustments by me
Discussion: https://postgr.es/m/CANFyU97OVQ3+Mzfmt3MhuUm5NwPU=-FtbNH5Eb7nZL9ua8=rcA@mail.gmail.com
The TAP tests mostly don't work without IPC::Run, and the reason for
the failure is not immediately obvious from the error messages you get.
So teach configure to reject --enable-tap-tests unless IPC::Run exists.
Mostly this just involves adding ax_prog_perl_modules.m4 from the GNU
autoconf archives.
This was discussed last year, but we held off on the theory that we might
be switching to CMake soon. That's evidently not happening for v10,
so let's absorb this now.
Eugene Kazakov and Michael Paquier
Discussion: https://postgr.es/m/56BDDC20.9020506@postgrespro.ru
Discussion: https://postgr.es/m/CAB7nPqRVKG_CR4Dy_AMfE6DXcr6F7ygy2goa2atJU4XkerDRUg@mail.gmail.com
This reverts commit 81069a9efc5a374dd39874a161f456f0fb3afba4.
Buildfarm results suggest that some platforms have versions of pselect(2)
that are not merely non-atomic, but flat out non-functional. Revert the
use-pselect patch to confirm this diagnosis (and exclude the no-SA_RESTART
patch as the source of trouble). If it's so, we should probably look into
blacklisting specific platforms that have broken pselect.
Discussion: https://postgr.es/m/9696.1493072081@sss.pgh.pa.us
Traditionally we've unblocked signals, called select(2), and then blocked
signals again. The code expects that the select() will be cancelled with
EINTR if an interrupt occurs; but there's a race condition, which is that
an already-pending signal will be delivered as soon as we unblock, and then
when we reach select() there will be nothing preventing it from waiting.
This can result in a long delay before we perform any action that
ServerLoop was supposed to have taken in response to the signal. As with
the somewhat-similar symptoms fixed by commit 893902085, the main practical
problem is slow launching of parallel workers. The window for trouble is
usually pretty short, corresponding to one iteration of ServerLoop; but
it's not negligible.
To fix, use pselect(2) in place of select(2) where available, as that's
designed to solve exactly this problem. Where not available, we continue
to use the old way, and are no worse off than before.
pselect(2) has been required by POSIX since about 2001, so most modern
platforms should have it. A bigger portability issue is that some
implementations are said to be non-atomic, ie pselect() isn't really
any different from unblock/select/reblock. Still, we're no worse off
than before on such a platform.
There is talk of rewriting the postmaster to use a WaitEventSet and
not do signal response work in signal handlers, at which point this
could be reverted, since we'd be using a self-pipe to solve the race
condition. But that's not happening before v11 at the earliest.
Back-patch to 9.6. The problem exists much further back, but the
worst symptom arises only in connection with parallel query, so it
does not seem worth taking any portability risks in older branches.
Discussion: https://postgr.es/m/9205.1492833041@sss.pgh.pa.us
poll.h is mandated by Single Unix Spec v2, the usual baseline for
postgres on unix. None of the unixoid buildfarms animals has
sys/poll.h but not poll.h. Therefore there's not much point to test
for sys/poll.h's existence and include it optionally.
Author: Andres Freund, per suggestion from Tom Lane
Discussion: https://postgr.es/m/20505.1492723662@sss.pgh.pa.us
All documentation is now built using XSLT. Remove all references to
Jade, DSSSL, also JadeTex and some other outdated tooling.
For chunked HTML builds, this changes nothing, but removes the
transitional "oldhtml" target. The single-page HTML build is ported
over to XSLT. For PDF builds, this removes the JadeTex builds and moves
the FOP builds in their place.
copyObject() is declared to return void *, which allows easily assigning
the result independent of the input, but it loses all type checking.
If the compiler supports typeof or something similar, cast the result to
the input type. This creates a greater amount of type safety. In some
cases, where the result is assigned to a generic type such as Node * or
Expr *, new casts are now necessary, but in general casts are now
unnecessary in the normal case and indicate that something unusual is
happening.
Reviewed-by: Mark Dilger <hornschnorter@gmail.com>
Add a column collprovider to pg_collation that determines which library
provides the collation data. The existing choices are default and libc,
and this adds an icu choice, which uses the ICU4C library.
The pg_locale_t type is changed to a union that contains the
provider-specific locale handles. Users of locale information are
changed to look into that struct for the appropriate handle to use.
Also add a collversion column that records the version of the collation
when it is created, and check at run time whether it is still the same.
This detects potentially incompatible library upgrades that can corrupt
indexes and other structures. This is currently only supported by
ICU-provided collations.
initdb initializes the default collation set as before from the `locale
-a` output but also adds all available ICU locales with a "-x-icu"
appended.
Currently, ICU-provided collations can only be explicitly named
collations. The global database locales are still always libc-provided.
ICU support is enabled by configure --with-icu.
Reviewed-by: Thomas Munro <thomas.munro@enterprisedb.com>
Reviewed-by: Andreas Karlsson <andreas@proxel.se>
We had some AC_CHECK_HEADER tests that were really wastes of cycles,
because the code proceeded to #include those headers unconditionally
anyway, in all or a large majority of cases. The lack of complaints
shows that those headers are available on every platform of interest,
so we might as well let configure run a bit faster by not probing
those headers at all.
I suspect that some of the tests I left alone are equally useless, but
since all the existing #includes of the remaining headers are properly
guarded, I didn't touch them.
Per discussion, the time has come to do this. The handwriting has been
on the wall at least since 9.0 that this would happen someday, whenever
it got to be too much of a burden to support the float-timestamp option.
The triggering factor now is the discovery that there are multiple bugs
in the code that attempts to implement use of integer timestamps in the
replication protocol even when the server is built for float timestamps.
The internal float timestamps leak into the protocol fields in places.
While we could fix the identified bugs, there's a very high risk of
introducing more. Trying to build a wall that would positively prevent
mixing integer and float timestamps is more complexity than we want to
undertake to maintain a long-deprecated option. The fact that these
bugs weren't found through testing also indicates a lack of interest
in float timestamps.
This commit disables configure's --disable-integer-datetimes switch
(it'll still accept --enable-integer-datetimes, though), removes direct
references to USE_INTEGER_DATETIMES, and removes discussion of float
timestamps from the user documentation. A considerable amount of code is
rendered dead by this, but removing that will occur as separate mop-up.
Discussion: https://postgr.es/m/26788.1487455319@sss.pgh.pa.us
Commit 04aad4018 added this check after the search for a Python shared
library, which seems to me to be a pretty unfriendly ordering. The
search might fail for what are basically version-related reasons, and
in such a case it'd be better to say "your Python is too old" than
"could not find shared library for Python".
