Clear OpenSSL error queue after failed X509_STORE_load_locations() call.
Leaving the error in the error queue used to be harmless, because the
X509_STORE_load_locations() call used to be the last step in
initialize_SSL(), and we would clear the queue before the next
SSL_connect() call. But previous commit moved things around. The symptom
was that if a CRL file was not found, and one of the subsequent
initialization steps, like loading the client certificate or private key,
failed, we would incorrectly print the "no such file" error message from
the earlier X509_STORE_load_locations() call as the reason.
Backpatch to all supported versions, like the previous patch.
1. There was a race condition, if two threads opened a connection at the
same time. We used a mutex around SSL_CTX_* calls, but that was not
enough, e.g. if one thread SSL_CTX_load_verify_locations() with one
path, and another thread set it with a different path, before the first
thread got to establish the connection.
2. Opening two different connections, with different sslrootcert settings,
seemed to fail outright with "SSL error: block type is not 01". Not sure
why.
3. We created the SSL object, before calling SSL_CTX_load_verify_locations
and SSL_CTX_use_certificate_chain_file on the SSL context. That was
wrong, because the options set on the SSL context are propagated to the
SSL object, when the SSL object is created. If they are set after the
SSL object has already been created, they won't take effect until the
next connection. (This is bug #14329)
At least some of these could've been fixed while still using a shared
context, but it would've been more complicated and error-prone. To keep
things simple, let's just use a separate SSL context for each connection,
and accept the overhead.
<sys/select.h> is required by POSIX.1-2001 to get the prototype of
select(2), but nearly no systems enforce that because older standards
let you get away with including some other headers. Recent OpenBSD
hacking has removed that frail touch of friendliness, however, which
broke some compiles; fix all the way back to 9.1 by adding the required
standard. Only vacuumdb.c was reported to fail, but it seems easier to
fix the whole lot in a fell swoop.
Tom Lane [Fri, 23 Sep 2016 18:22:07 +0000 (14:22 -0400)]
Doc: fix examples of # operators so they actually work.
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.
Tom Lane [Fri, 23 Sep 2016 17:49:27 +0000 (13:49 -0400)]
Fix incorrect logic for excluding range constructor functions in pg_dump.
Faulty AND/OR nesting in the WHERE clause of getFuncs' SQL query led to
dumping range constructor functions if they are part of an extension
and we're in binary-upgrade mode. Actually, we don't want to dump them
separately even then, since CREATE TYPE AS RANGE will create the range's
constructor functions regardless. Per report from Andrew Dunstan.
It looks like this mistake was introduced by me, in commit b985d4877, in
perhaps-overzealous refactoring to reduce code duplication. I'm suitably
embarrassed.
Tom Lane [Thu, 22 Sep 2016 15:34:44 +0000 (11:34 -0400)]
Be sure to rewind the tuplestore read pointer in non-leader CTEScan nodes.
ExecInitCteScan supposed that it didn't have to do anything to the extra
tuplestore read pointer it gets from tuplestore_alloc_read_pointer.
However, it needs this read pointer to be positioned at the start of the
tuplestore, while tuplestore_alloc_read_pointer is actually defined as
cloning the current position of read pointer 0. In normal situations
that accidentally works because we initialize the whole plan tree at once,
before anything gets read. But it fails in an EvalPlanQual recheck, as
illustrated in bug #14328 from Dima Pavlov. To fix, just forcibly rewind
the pointer after tuplestore_alloc_read_pointer. The cost of doing so is
negligible unless the tuplestore is already in TSS_READFILE state, which
wouldn't happen in normal cases. We could consider altering tuplestore's
API to make that case cheaper, but that would make for a more invasive
back-patch and it doesn't seem worth it.
This has been broken probably for as long as we've had CTEs, so back-patch
to all supported branches.
Fix ecpg -? option on Windows, add -V alias for --version.
This makes the -? and -V options work consistently with other binaries.
--help and --version are now only recognized as the first option, i.e.
"ecpg --foobar --help" no longer prints the help, but that's consistent
with most of our other binaries, too.
Andres Freund [Thu, 8 Sep 2016 23:51:09 +0000 (16:51 -0700)]
Fix mdtruncate() to close fd.c handle of deleted segments.
mdtruncate() forgot to FileClose() a segment's mdfd_vfd, when deleting
it. That lead to a fd.c handle to a truncated file being kept open until
backend exit.
The issue appears to have been introduced way back in 1a5c450f3024ac5,
before that the handle was closed inside FileUnlink().
The impact of this bug is limited - only VACUUM and ON COMMIT TRUNCATE
for temporary tables, truncate files in place (i.e. TRUNCATE itself is
not affected), and the relation has to be bigger than 1GB. The
consequences of a leaked fd.c handle aren't severe either.
Discussion: <20160908220748.oqh37ukwqqncbl3n@alap3.anarazel.de>
Backpatch: all supported releases
Tom Lane [Mon, 5 Sep 2016 00:02:16 +0000 (20:02 -0400)]
Add regression test coverage for non-default timezone abbreviation sets.
After further reflection about the mess cleaned up in commit 39b691f25,
I decided the main bit of test coverage that was still missing was to
check that the non-default abbreviation-set files we supply are usable.
Add that.
Back-patch to supported branches, just because it seems like a good
idea to keep this all in sync.
Tom Lane [Sun, 4 Sep 2016 23:42:08 +0000 (19:42 -0400)]
Remove vestigial references to "zic" in favor of "IANA database".
Commit b2cbced9e instituted a policy of referring to the timezone database
as the "IANA timezone database" in our user-facing documentation.
Propagate that wording into a couple of places that were still using "zic"
to refer to the database, which is definitely not right (zic is the
compilation tool, not the data).
Back-patch, not because this is very important in itself, but because
we routinely cherry-pick updates to the tznames files and I don't want
to risk future merge failures.
Tom Lane [Fri, 2 Sep 2016 21:29:32 +0000 (17:29 -0400)]
Don't require dynamic timezone abbreviations to match underlying time zone.
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 b2cbced9e 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.
Tom Lane [Wed, 31 Aug 2016 12:52:13 +0000 (08:52 -0400)]
Prevent starting a standalone backend with standby_mode on.
This can't really work because standby_mode expects there to be more
WAL arriving, which there will not ever be because there's no WAL
receiver process to fetch it. Moreover, if standby_mode is on then
hot standby might also be turned on, causing even more strangeness
because that expects read-only sessions to be executing in parallel.
Bernd Helmle reported a case where btree_xlog_delete_get_latestRemovedXid
got confused, but rather than band-aiding individual problems it seems
best to prevent getting anywhere near this state in the first place.
Back-patch to all supported branches.
In passing, also fix some omissions of errcodes in other ereport's in
readRecoveryCommandFile().
Tom Lane [Thu, 25 Aug 2016 13:57:09 +0000 (09:57 -0400)]
Fix instability in parallel regression tests.
Commit f0c7b789a added a test case in case.sql that creates and then drops
both an '=' operator and the type it's for. Given the right timing, that
can cause a "cache lookup failed for type" failure in concurrent sessions,
which see the '=' operator as a potential match for '=' in a query, but
then the type is gone by the time they inquire into its properties.
It might be nice to make that behavior more robust someday, but as a
back-patchable solution, adjust the new test case so that the operator
is never visible to other sessions. Like the previous commit, back-patch
to all supported branches.
Tom Lane [Wed, 24 Aug 2016 18:37:51 +0000 (14:37 -0400)]
Fix improper repetition of previous results from a hashed aggregate.
ExecReScanAgg's check for whether it could re-use a previously calculated
hashtable neglected the possibility that the Agg node might reference
PARAM_EXEC Params that are not referenced by its input plan node. That's
okay if the Params are in upper tlist or qual expressions; but if one
appears in aggregate input expressions, then the hashtable contents need
to be recomputed when the Param's value changes.
To avoid unnecessary performance degradation in the case of a Param that
isn't within an aggregate input, add logic to the planner to determine
which Params are within aggregate inputs. This requires a new field in
struct Agg, but fortunately we never write plans to disk, so this isn't
an initdb-forcing change.
Per report from Jeevan Chalke. This has been broken since forever,
so back-patch to all supported branches.
Magnus Hagander [Thu, 18 Aug 2016 10:32:42 +0000 (12:32 +0200)]
Update Windows timezone mapping from Windows 7 and 10
This adds a couple of new timezones that are present in the newer
versions of Windows. It also updates comments to reference UTC rather
than GMT, as this change has been made in Windows.
Tom Lane [Wed, 17 Aug 2016 19:51:11 +0000 (15:51 -0400)]
Fix -e option in contrib/intarray/bench/bench.pl.
As implemented, -e ran an EXPLAIN but then discarded the output, which
certainly seems pointless. Make it print to stdout instead. It's been
like that forever, so back-patch to all supported branches.
Tom Lane [Sun, 14 Aug 2016 19:06:02 +0000 (15:06 -0400)]
Remove bogus dependencies on NUMERIC_MAX_PRECISION.
NUMERIC_MAX_PRECISION is a purely arbitrary constraint on the precision
and scale you can write in a numeric typmod. It might once have had
something to do with the allowed range of a typmod-less numeric value,
but at least since 9.1 we've allowed, and documented that we allowed,
any value that would physically fit in the numeric storage format;
which is something over 100000 decimal digits, not 1000.
Hence, get rid of numeric_in()'s use of NUMERIC_MAX_PRECISION as a limit
on the allowed range of the exponent in scientific-format input. That was
especially silly in view of the fact that you can enter larger numbers as
long as you don't use 'e' to do it. Just constrain the value enough to
avoid localized overflow, and let make_result be the final arbiter of what
is too large. Likewise adjust ecpg's equivalent of this code.
Also get rid of numeric_recv()'s use of NUMERIC_MAX_PRECISION to limit the
number of base-NBASE digits it would accept. That created a dump/restore
hazard for binary COPY without doing anything useful; the wire-format
limit on number of digits (65535) is about as tight as we would want.
In HEAD, also get rid of pg_size_bytes()'s unnecessary intimacy with what
the numeric range limit is. That code doesn't exist in the back branches.
Per gripe from Aravind Kumar. Back-patch to all supported branches,
since they all contain the documentation claim about allowed range of
NUMERIC (cf commit cabf5d84b).
Tom Lane [Sat, 13 Aug 2016 00:51:59 +0000 (20:51 -0400)]
Fix regression test parallel-make hazard.
Back-patch 9.4-era commit 384f933046dc9e9a2b416f5f7b3be30b93587c63 into
the previous branches. Although that was only advertised as repairing a
problem with missed header-file dependencies, it turns out to also be
important for parallel make safety. The previous coding allowed two
independent make jobs to get launched concurrently in contrib/spi.
Normally this would be OK, because they are building independent targets;
but if --enable-depend is in use, it's unsafe, because one make run might
try to read a .deps file that the other one is in process of rewriting.
This is evidently the cause of buildfarm member francolin's recent failure
in the 9.2 branch. I believe this patch will result in only one subsidiary
make run, making it safe(r).
Tom Lane [Fri, 12 Aug 2016 16:13:04 +0000 (12:13 -0400)]
Fix inappropriate printing of never-measured times in EXPLAIN.
EXPLAIN (ANALYZE, TIMING OFF) would print an elapsed time of zero for
a trigger function, because no measurement has been taken but it printed
the field anyway. This isn't what EXPLAIN does elsewhere, so suppress it.
In the same vein, EXPLAIN (ANALYZE, BUFFERS) with non-text output format
would print buffer I/O timing numbers even when no measurement has been
taken because track_io_timing is off. That seems not per policy, either,
so change it.
Back-patch to 9.2 where these features were introduced.
Fix several one-byte buffer over-reads in to_number
Several places in NUM_numpart_from_char(), which is called from the SQL
function to_number(text, text), could accidentally read one byte past
the end of the input buffer (which comes from the input text datum and
is not null-terminated).
1. One leading space character would be skipped, but there was no check
that the input was at least one byte long. This does not happen in
practice, but for defensiveness, add a check anyway.
2. Commit 4a3a1e2cf apparently accidentally doubled that code that skips
one space character (so that two spaces might be skipped), but there
was no overflow check before skipping the second byte. Fix by
removing that duplicate code.
3. A logic error would allow a one-byte over-read when looking for a
trailing sign (S) placeholder.
In each case, the extra byte cannot be read out directly, but looking at
it might cause a crash.
The third item was discovered by Piotr Stefaniak, the first two were
found and analyzed by Tom Lane and Peter Eisentraut.
Tom Lane [Mon, 8 Aug 2016 14:33:47 +0000 (10:33 -0400)]
Fix two errors with nested CASE/WHEN constructs.
ExecEvalCase() tried to save a cycle or two by passing
&econtext->caseValue_isNull as the isNull argument to its sub-evaluation of
the CASE value expression. If that subexpression itself contained a CASE,
then *isNull was an alias for econtext->caseValue_isNull within the
recursive call of ExecEvalCase(), leading to confusion about whether the
inner call's caseValue was null or not. In the worst case this could lead
to a core dump due to dereferencing a null pointer. Fix by not assigning
to the global variable until control comes back from the subexpression.
Also, avoid using the passed-in isNull pointer transiently for evaluation
of WHEN expressions. (Either one of these changes would have been
sufficient to fix the known misbehavior, but it's clear now that each of
these choices was in itself dangerous coding practice and best avoided.
There do not seem to be any similar hazards elsewhere in execQual.c.)
Also, it was possible for inlining of a SQL function that implements the
equality operator used for a CASE comparison to result in one CASE
expression's CaseTestExpr node being inserted inside another CASE
expression. This would certainly result in wrong answers since the
improperly nested CaseTestExpr would be caused to return the inner CASE's
comparison value not the outer's. If the CASE values were of different
data types, a crash might result; moreover such situations could be abused
to allow disclosure of portions of server memory. To fix, teach
inline_function to check for "bare" CaseTestExpr nodes in the arguments of
a function to be inlined, and avoid inlining if there are any.
Noah Misch [Mon, 8 Aug 2016 14:07:46 +0000 (10:07 -0400)]
Obstruct shell, SQL, and conninfo injection via database and role names.
Due to simplistic quoting and confusion of database names with conninfo
strings, roles with the CREATEDB or CREATEROLE option could escalate to
superuser privileges when a superuser next ran certain maintenance
commands. The new coding rule for PQconnectdbParams() calls, documented
at conninfo_array_parse(), is to pass expand_dbname=true and wrap
literal database names in a trivial connection string. Escape
zero-length values in appendConnStrVal(). Back-patch to 9.1 (all
supported versions).
Nathan Bossart, Michael Paquier, and Noah Misch. Reviewed by Peter
Eisentraut. Reported by Nathan Bossart.
Noah Misch [Mon, 8 Aug 2016 14:07:46 +0000 (10:07 -0400)]
Promote pg_dumpall shell/connstr quoting functions to src/fe_utils.
Rename these newly-extern functions with terms more typical of their new
neighbors. No functional changes; a subsequent commit will use them in
more places. Back-patch to 9.1 (all supported versions). Back branches
lack src/fe_utils, so instead rename the functions in place; the
subsequent commit will copy them into the other programs using them.
Noah Misch [Mon, 8 Aug 2016 14:07:46 +0000 (10:07 -0400)]
Fix Windows shell argument quoting.
The incorrect quoting may have permitted arbitrary command execution.
At a minimum, it gave broader control over the command line to actors
supposed to have control over a single argument. Back-patch to 9.1 (all
supported versions).
Noah Misch [Mon, 8 Aug 2016 14:07:46 +0000 (10:07 -0400)]
Reject, in pg_dumpall, names containing CR or LF.
These characters prematurely terminate Windows shell command processing,
causing the shell to execute a prefix of the intended command. The
chief alternative to rejecting these characters was to bypass the
Windows shell with CreateProcess(), but the ability to use such names
has little value. Back-patch to 9.1 (all supported versions).
This change formally revokes support for these characters in database
names and roles names. Don't document this; the error message is
self-explanatory, and too few users would benefit. A future major
release may forbid creation of databases and roles so named. For now,
check only at known weak points in pg_dumpall. Future commits will,
without notice, reject affected names from other frontend programs.
Also extend the restriction to pg_dumpall --dbname=CONNSTR arguments and
--file arguments. Unlike the effects on role name arguments and
database names, this does not reflect a broad policy change. A
migration to CreateProcess() could lift these two restrictions.
Noah Misch [Mon, 8 Aug 2016 14:07:46 +0000 (10:07 -0400)]
Field conninfo strings throughout src/bin/scripts.
These programs nominally accepted conninfo strings, but they would
proceed to use the original dbname parameter as though it were an
unadorned database name. This caused "reindexdb dbname=foo" to issue an
SQL command that always failed, and other programs printed a conninfo
string in error messages that purported to print a database name. Fix
both problems by using PQdb() to retrieve actual database names.
Continue to print the full conninfo string when reporting a connection
failure. It is informative there, and if the database name is the sole
problem, the server-side error message will include the name. Beyond
those user-visible fixes, this allows a subsequent commit to synthesize
and use conninfo strings without that implementation detail leaking into
messages. As a side effect, the "vacuuming database" message now
appears after, not before, the connection attempt. Back-patch to 9.1
(all supported versions).
Noah Misch [Mon, 8 Aug 2016 14:07:46 +0000 (10:07 -0400)]
Introduce a psql "\connect -reuse-previous=on|off" option.
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.
Noah Misch [Mon, 8 Aug 2016 14:07:46 +0000 (10:07 -0400)]
Sort out paired double quotes in \connect, \password and \crosstabview.
In arguments, these meta-commands wrongly treated each pair as closing
the double quoted string. Make the behavior match the documentation.
This is a compatibility break, but I more expect to find software with
untested reliance on the documented behavior than software reliant on
today's behavior. Back-patch to 9.1 (all supported versions).
Tom Lane [Sun, 7 Aug 2016 22:52:02 +0000 (18:52 -0400)]
Fix misestimation of n_distinct for a nearly-unique column with many nulls.
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
Tom Lane [Fri, 5 Aug 2016 22:58:12 +0000 (18:58 -0400)]
Teach libpq to decode server version correctly from future servers.
Beginning with the next development cycle, PG servers will report two-part
not three-part version numbers. Fix libpq so that it will compute the
correct numeric representation of such server versions for reporting by
PQserverVersion(). It's desirable to get this into the field and
back-patched ASAP, so that older clients are more likely to understand the
new server version numbering by the time any such servers are in the wild.
(The results with an old client would probably not be catastrophic anyway
for a released server; for example "10.1" would be interpreted as 100100
which would be wrong in detail but would not likely cause an old client to
misbehave badly. But "10devel" or "10beta1" would result in sversion==0
which at best would result in disabling all use of modern features.)
Extracted from a patch by Peter Eisentraut; comments added by me
Tom Lane [Fri, 5 Aug 2016 16:58:17 +0000 (12:58 -0400)]
Update time zone data files to tzdata release 2016f.
DST law changes in Kemerovo and Novosibirsk. Historical corrections for
Azerbaijan, Belarus, and Morocco. Asia/Novokuznetsk and Asia/Novosibirsk
now use numeric time zone abbreviations instead of invented ones. Zones
for Antarctic bases and other locations that have been uninhabited for
portions of the time span known to the tzdata database now report "-00"
rather than "zzz" as the zone abbreviation for those time spans.
Also, I decided to remove some of the timezone/data/ files that we don't
use. At one time that subdirectory was a complete copy of what IANA
distributes in the tzdata tarballs, but that hasn't been true for a long
time. There seems no good reason to keep shipping those specific files
but not others; they're just bloating our tarballs.
Tom Lane [Tue, 2 Aug 2016 16:48:51 +0000 (12:48 -0400)]
Fix pg_dump's handling of public schema with both -c and -C options.
Since -c plus -C requests dropping and recreating the target database
as a whole, not dropping individual objects in it, we should assume that
the public schema already exists and need not be created. The previous
coding considered only the state of the -c option, so it would emit
"CREATE SCHEMA public" anyway, leading to an unexpected error in restore.
Back-patch to 9.2. Older versions did not accept -c with -C so the
issue doesn't arise there. (The logic being patched here dates to 8.0,
cf commit 2193121fa, so it's not really wrong that it didn't consider
the case at the time.)
Note that versions before 9.6 will still attempt to emit REVOKE/GRANT
on the public schema; but that happens without -c/-C too, and doesn't
seem to be the focus of this complaint. I considered extending this
stanza to also skip the public schema's ACL, but that would be a
misfeature, as it'd break cases where users intentionally changed that
ACL. The real fix for this aspect is Stephen Frost's work to not dump
built-in ACLs, and that's not going to get back-ported.
Per bugs #13804 and #14271. Solution found by David Johnston and later
rediscovered by me.
Fujii Masao [Mon, 1 Aug 2016 08:36:14 +0000 (17:36 +0900)]
Fix pg_basebackup so that it accepts 0 as a valid compression level.
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
Tom Lane [Sun, 31 Jul 2016 22:32:34 +0000 (18:32 -0400)]
Doc: remove claim that hash index creation depends on effective_cache_size.
This text was added by commit ff213239c, and not long thereafter obsoleted
by commit 4adc2f72a (which made the test depend on NBuffers instead); but
nobody noticed the need for an update. Commit 9563d5b5e 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.)
Tom Lane [Thu, 28 Jul 2016 22:57:24 +0000 (18:57 -0400)]
Guard against empty buffer in gets_fromFile()'s check for a newline.
Per the fgets() specification, it cannot return without reading some data
unless it reports EOF or error. So the code here assumed that the data
buffer would necessarily be nonempty when we go to check for a newline
having been read. However, Agostino Sarubbo noticed that this could fail
to be true if the first byte of the data is a NUL (\0). The fgets() API
doesn't really work for embedded NULs, which is something I don't feel
any great need for us to worry about since we generally don't allow NULs
in SQL strings anyway. But we should not access off the end of our own
buffer if the case occurs. Normally this would just be a harmless read,
but if you were unlucky the byte before the buffer would contain '\n'
and we'd overwrite it with '\0', and if you were really unlucky that
might be valuable data and psql would crash.
Agostino reported this to pgsql-security, but after discussion we concluded
that it isn't worth treating as a security bug; if you can control the
input to psql you can do far more interesting things than just maybe-crash
it. Nonetheless, it is a bug, so back-patch to all supported versions.
Tom Lane [Thu, 28 Jul 2016 20:09:15 +0000 (16:09 -0400)]
Fix assorted fallout from IS [NOT] NULL patch.
Commits 4452000f3 et al established semantics for NullTest.argisrow that
are a bit different from its initial conception: rather than being merely
a cache of whether we've determined the input to have composite type,
the flag now has the further meaning that we should apply field-by-field
testing as per the standard's definition of IS [NOT] NULL. If argisrow
is false and yet the input has composite type, the construct instead has
the semantics of IS [NOT] DISTINCT FROM NULL. Update the comments in
primnodes.h to clarify this, and fix ruleutils.c and deparse.c to print
such cases correctly. In the case of ruleutils.c, this merely results in
cosmetic changes in EXPLAIN output, since the case can't currently arise
in stored rules. However, it represents a live bug for deparse.c, which
would formerly have sent a remote query that had semantics different
from the local behavior. (From the user's standpoint, this means that
testing a remote nested-composite column for null-ness could have had
unexpected recursive behavior much like that fixed in 4452000f3.)
In a related but somewhat independent fix, make plancat.c set argisrow
to false in all NullTest expressions constructed to represent "attnotnull"
constructs. Since attnotnull is actually enforced as a simple null-value
check, this is a more accurate representation of the semantics; we were
previously overpromising what it meant for composite columns, which might
possibly lead to incorrect planner optimizations. (It seems that what the
SQL spec expects a NOT NULL constraint to mean is an IS NOT NULL test, so
arguably we are violating the spec and should fix attnotnull to do the
other thing. If we ever do, this part should get reverted.)
Tom Lane [Thu, 28 Jul 2016 17:26:59 +0000 (13:26 -0400)]
Improve documentation about CREATE TABLE ... LIKE.
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.
Tom Lane [Thu, 28 Jul 2016 15:39:11 +0000 (11:39 -0400)]
Register atexit hook only once in pg_upgrade.
start_postmaster() registered stop_postmaster_atexit as an atexit(3)
callback each time through, although the obvious intention was to do
so only once per program run. The extra registrations were harmless,
so long as we didn't exceed ATEXIT_MAX, but still it's a bug.
Artur Zakirov, with bikeshedding by Kyotaro Horiguchi and me
Tom Lane [Tue, 26 Jul 2016 19:25:02 +0000 (15:25 -0400)]
Fix constant-folding of ROW(...) IS [NOT] NULL with composite fields.
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.
Tom Lane [Thu, 21 Jul 2016 20:52:36 +0000 (16:52 -0400)]
Make contrib regression tests safe for Danish locale.
In btree_gin and citext, avoid some not-particularly-interesting
dependencies on the sorting of 'aa'. In tsearch2, use COLLATE "C" to
remove an uninteresting dependency on locale sort order (and thereby
allow removal of a variant expected-file).
Also, in citext, avoid assuming that lower('I') = 'i'. This isn't relevant
to Danish but it does fail in Turkish.
Tom Lane [Thu, 21 Jul 2016 18:24:07 +0000 (14:24 -0400)]
Make pltcl regression tests safe for Danish locale.
Another peculiarity of Danish locale is that it has an unusual idea
of how to sort upper vs. lower case. One of the pltcl test cases has
an issue with that. Now that COLLATE works in all supported branches,
we can just change the test to be locale-independent, and get rid of
the variant expected file that used to support non-C locales.
Tom Lane [Tue, 19 Jul 2016 19:59:36 +0000 (15:59 -0400)]
Sync back-branch copies of the timezone code with IANA release tzcode2016c.
Back-patch commit 1c1a7cbd6a1600c9, along with subsequent portability
fixes, into all active branches. Also, back-patch commits 696027727 and 596857043 (addition of zic -P option) into 9.1 and 9.2, just to reduce
differences between the branches. src/timezone/ is now largely identical
in all active branches, except that in 9.1, pgtz.c retains the
initial-timezone-selection code that was moved over to initdb in 9.2.
Ordinarily we wouldn't risk this much code churn in back branches, but it
seems necessary in this case, because among the changes are two feature
additions in the "zic" zone data file compiler (a larger limit on the
number of allowed DST transitions, and addition of a "%z" escape in zone
abbreviations). IANA have not yet started to use those features in their
tzdata files, but presumably they will before too long. If we don't update
then we'll be unable to adopt new timezone data. Also, installations built
with --with-system-tzdata (which includes most distro-supplied builds, I
believe) might fail even if we don't update our copies of the data files.
There are assorted bug fixes too, mostly affecting obscure timezones or
post-2037 dates.
Peter Eisentraut [Sun, 17 Jul 2016 13:37:33 +0000 (09:37 -0400)]
Use correct symbol for minimum int64 value
The old code used SEQ_MINVALUE to get the smallest int64 value. This
was done as a convenience to avoid having to deal with INT64_IS_BUSTED,
but that is obsolete now. Also, it is incorrect because the smallest
int64 value is actually SEQ_MINVALUE-1. Fix by writing out the constant
the long way, as it is done elsewhere in the code.
Tom Lane [Sat, 16 Jul 2016 18:42:37 +0000 (14:42 -0400)]
Fix crash in close_ps() for NaN input coordinates.
The Assert() here seems unreasonably optimistic. Andreas Seltenreich
found that it could fail with NaNs in the input geometries, and it
seems likely to me that it might fail in corner cases due to roundoff
error, even for ordinary input values. As a band-aid, make the function
return SQL NULL instead of crashing.
Andres Freund [Sat, 16 Jul 2016 00:49:48 +0000 (17:49 -0700)]
Fix torn-page, unlogged xid and further risks from heap_update().
When heap_update needs to look for a page for the new tuple version,
because the current one doesn't have sufficient free space, or when
columns have to be processed by the tuple toaster, it has to release the
lock on the old page during that. Otherwise there'd be lock ordering and
lock nesting issues.
To avoid concurrent sessions from trying to update / delete / lock the
tuple while the page's content lock is released, the tuple's xmax is set
to the current session's xid.
That unfortunately was done without any WAL logging, thereby violating
the rule that no XIDs may appear on disk, without an according WAL
record. If the database were to crash / fail over when the page level
lock is released, and some activity lead to the page being written out
to disk, the xid could end up being reused; potentially leading to the
row becoming invisible.
There might be additional risks by not having t_ctid point at the tuple
itself, without having set the appropriate lock infomask fields.
To fix, compute the appropriate xmax/infomask combination for locking
the tuple, and perform WAL logging using the existing XLOG_HEAP_LOCK
record. That allows the fix to be backpatched.
This issue has existed for a long time. There appears to have been
partial attempts at preventing dangers, but these never have fully been
implemented, and were removed a long time ago, in 11919160 (cf. HEAP_XMAX_UNLOGGED).
In master / 9.6, there's an additional issue, namely that the
visibilitymap's freeze bit isn't reset at that point yet. Since that's a
new issue, introduced only in a892234f830, that'll be fixed in a
separate commit.
Author: Masahiko Sawada and Andres Freund Reported-By: Different aspects by Thomas Munro, Noah Misch, and others
Discussion: CAEepm=3fWAbWryVW9swHyLTY4sXVf0xbLvXqOwUoDiNCx9mBjQ@mail.gmail.com
Backpatch: 9.1/all supported versions
Tom Lane [Thu, 14 Jul 2016 22:46:00 +0000 (18:46 -0400)]
Fix GiST index build for NaN values in geometric types.
GiST index build could go into an infinite loop when presented with boxes
(or points, circles or polygons) containing NaN component values. This
happened essentially because the code assumed that x == x is true for any
"double" value x; but it's not true for NaNs. The looping behavior was not
the only problem though: we also attempted to sort the items using simple
double comparisons. Since NaNs violate the trichotomy law, qsort could
(in principle at least) get arbitrarily confused and mess up the sorting of
ordinary values as well as NaNs. And we based splitting choices on box size
calculations that could produce NaNs, again resulting in undesirable
behavior.
To fix, replace all comparisons of doubles in this logic with
float8_cmp_internal, which is NaN-aware and is careful to sort NaNs
consistently, higher than any non-NaN. Also rearrange the box size
calculation to not produce NaNs; instead it should produce an infinity
for a box with NaN on one side and not-NaN on the other.
I don't by any means claim that this solves all problems with NaNs in
geometric values, but it should at least make GiST index insertion work
reliably with such data. It's likely that the index search side of things
still needs some work, and probably regular geometric operations too.
But with this patch we're laying down a convention for how such cases
ought to behave.
Per bug #14238 from Guang-Dih Lei. Back-patch to 9.2; the code used before
commit 7f3bd86843e5aad8 is quite different and doesn't lock up on my simple
test case, nor on the submitter's dataset.
Bruce Momjian [Sat, 2 Jul 2016 15:22:35 +0000 (11:22 -0400)]
doc: mention dependency on collation libraries
Document that index storage is dependent on the operating system's
collation library ordering, and any change in that ordering can create
invalid indexes.
Tom Lane [Wed, 22 Jun 2016 15:55:18 +0000 (11:55 -0400)]
Make "postgres -C guc" print "" not "(null)" for null-valued GUCs.
Commit 0b0baf262 et al made this case print "(null)" on the grounds that
that's what happened on platforms that didn't crash. But neither behavior
was actually intentional. What we should print is just an empty string,
for compatibility with the behavior of SHOW and other ways of examining
string GUCs. Those code paths don't distinguish NULL from empty strings,
so we should not here either. Per gripe from Alain Radix.
Like the previous patch, back-patch to 9.2 where -C option was introduced.
Tom Lane [Wed, 22 Jun 2016 00:07:58 +0000 (20:07 -0400)]
Document that dependency tracking doesn't consider function bodies.
If there's anyplace in our SGML docs that explains this behavior, I can't
find it right at the moment. Add an explanation in "Dependency Tracking"
which seems like the authoritative place for such a discussion. Per
gripe from Michelle Schwan.
While at it, update this section's example of a dependency-related
error message: they last looked like that in 8.3. And remove the
explanation of dependency updates from pre-7.3 installations, which
is probably no longer worth anybody's brain cells to read.
The bogus error message example seems like an actual documentation bug,
so back-patch to all supported branches.
Tom Lane [Sun, 19 Jun 2016 17:11:40 +0000 (13:11 -0400)]
Docs: improve description of psql's %R prompt escape sequence.
Dilian Palauzov pointed out in bug #14201 that the docs failed to mention
the possibility of %R producing '(' due to an unmatched parenthesis.
He proposed just adding that in the same style as the other options were
listed; but it seemed to me that the sentence was already nearly
unintelligible, so I rewrote it a bit more extensively.
Tom Lane [Thu, 16 Jun 2016 21:16:32 +0000 (17:16 -0400)]
Fix validation of overly-long IPv6 addresses.
The inet/cidr types sometimes failed to reject IPv6 inputs with too many
colon-separated fields, instead translating them to '::/0'. This is the
result of a thinko in the original ISC code that seems to be as yet
unreported elsewhere. Per bug #14198 from Stefan Kaltenbrunner.
Tom Lane [Thu, 16 Jun 2016 16:17:03 +0000 (12:17 -0400)]
Avoid crash in "postgres -C guc" for a GUC with a null string value.
Emit "(null)" instead, which was the behavior all along on platforms
that don't crash, eg OS X. Per report from Jehan-Guillaume de Rorthais.
Back-patch to 9.2 where -C option was introduced.
Tom Lane [Mon, 13 Jun 2016 17:53:10 +0000 (13:53 -0400)]
Fix multiple minor infelicities in aclchk.c error reports.
pg_type_aclmask reported the wrong type's OID when complaining that
it could not find a type's typelem. It also failed to provide a
suitable errcode when the initially given OID doesn't exist (which
is a user-facing error, since that OID can be user-specified).
pg_foreign_data_wrapper_aclmask and pg_foreign_server_aclmask likewise
lacked errcode specifications. Trivial cosmetic adjustments too.
The wrong-type-OID problem was reported by Petru-Florin Mihancea in
bug #14186; the other issues noted by me while reading the code.
These errors all seem to be aboriginal in the respective routines, so
back-patch as necessary.
Tom Lane [Thu, 9 Jun 2016 15:58:00 +0000 (11:58 -0400)]
Clarify documentation of ceil/ceiling/floor functions.
Document these as "nearest integer >= argument" and "nearest integer <=
argument", which will hopefully be less confusing than the old formulation.
New wording is from Matlab via Dean Rasheed.
I changed the pg_description entries as well as the SGML docs. In the
back branches, this will only affect installations initdb'd in the future,
but it should be harmless otherwise.
Alvaro Herrera [Tue, 7 Jun 2016 22:55:18 +0000 (18:55 -0400)]
nls-global.mk: search build dir for source files, too
In VPATH builds, the build directory was not being searched for files in
GETTEXT_FILES, leading to failure to construct the .pot files. This has
bit me all along, but never hard enough to get it fixed; I suppose not a
lot of people uses VPATH and NLS-enabled builds, and those that do,
don't do "make update-po" often.
This is a longstanding problem, so backpatch all the way back.
Tom Lane [Mon, 6 Jun 2016 21:44:18 +0000 (17:44 -0400)]
Don't reset changes_since_analyze after a selective-columns ANALYZE.
If we ANALYZE only selected columns of a table, we should not postpone
auto-analyze because of that; other columns may well still need stats
updates. As committed, the counter is left alone if a column list is
given, whether or not it includes all analyzable columns of the table.
Per complaint from Tomasz Ostrowski.
It's been like this a long time, so back-patch to all supported branches.
Alvaro Herrera [Wed, 25 May 2016 23:39:49 +0000 (19:39 -0400)]
Avoid hot standby cancels from VAC FREEZE
VACUUM FREEZE generated false cancelations of standby queries on an
otherwise idle master. Caused by an off-by-one error on cutoff_xid
which goes back to original commit.
Analysis and report by Marco Nenciarini
Bug fix by Simon Riggs
This is a correct backpatch of commit 66fbcb0d2e to branches 9.1 through
9.4. That commit was backpatched to 9.0 originally, but it was
immediately reverted in 9.0-9.4 because it didn't compile.
Tom Lane [Tue, 24 May 2016 19:47:51 +0000 (15:47 -0400)]
Fetch XIDs atomically during vac_truncate_clog().
Because vac_update_datfrozenxid() updates datfrozenxid and datminmxid
in-place, it's unsafe to assume that successive reads of those values will
give consistent results. Fetch each one just once to ensure sane behavior
in the minimum calculation. Noted while reviewing Alexander Korotkov's
patch in the same area.
Tom Lane [Tue, 24 May 2016 19:20:12 +0000 (15:20 -0400)]
Avoid consuming an XID during vac_truncate_clog().
vac_truncate_clog() uses its own transaction ID as the comparison point in
a sanity check that no database's datfrozenxid has already wrapped around
"into the future". That was probably fine when written, but in a lazy
vacuum we won't have assigned an XID, so calling GetCurrentTransactionId()
causes an XID to be assigned when otherwise one would not be. Most of the
time that's not a big problem ... but if we are hard up against the
wraparound limit, consuming XIDs during antiwraparound vacuums is a very
bad thing.
Instead, use ReadNewTransactionId(), which not only avoids this problem
but is in itself a better comparison point to test whether wraparound
has already occurred.
Report and patch by Alexander Korotkov. Back-patch to all versions.
Tom Lane [Mon, 23 May 2016 18:16:41 +0000 (14:16 -0400)]
Fix latent crash in do_text_output_multiline().
do_text_output_multiline() would fail (typically with a null pointer
dereference crash) if its input string did not end with a newline. Such
cases do not arise in our current sources; but it certainly could happen
in future, or in extension code's usage of the function, so we should fix
it. To fix, replace "eol += len" with "eol = text + len".
While at it, make two cosmetic improvements: mark the input string const,
and rename the argument from "text" to "txt" to dodge pgindent strangeness
(since "text" is a typedef name).
Even though this problem is only latent at present, it seems like a good
idea to back-patch the fix, since it's a very simple/safe patch and it's
not out of the realm of possibility that we might in future back-patch
something that expects sane behavior from do_text_output_multiline().
Tom Lane [Fri, 13 May 2016 00:04:12 +0000 (20:04 -0400)]
Ensure plan stability in contrib/btree_gist regression test.
Buildfarm member skink failed with symptoms suggesting that an
auto-analyze had happened and changed the plan displayed for a
test query. Although this is evidently of low probability,
regression tests that sometimes fail are no fun, so add commands
to force a bitmap scan to be chosen.
Alvaro Herrera [Tue, 10 May 2016 19:23:54 +0000 (16:23 -0300)]
Fix autovacuum for shared relations
The table-skipping logic in autovacuum would fail to consider that
multiple workers could be processing the same shared catalog in
different databases. This normally wouldn't be a problem: firstly
because autovacuum workers not for wraparound would simply ignore tables
in which they cannot acquire lock, and secondly because most of the time
these tables are small enough that even if multiple for-wraparound
workers are stuck in the same catalog, they would be over pretty
quickly. But in cases where the catalogs are severely bloated it could
become a problem.
Backpatch all the way back, because the problem has been there since the
beginning.
OpenSSL has an unfortunate tendency to mix per-session state error
handling with per-thread error handling. This can cause problems when
programs that link to libpq with OpenSSL enabled have some other use of
OpenSSL; without care, one caller of OpenSSL may cause problems for the
other caller. Backend code might similarly be affected, for example
when a third party extension independently uses OpenSSL without taking
the appropriate precautions.
To fix, don't trust other users of OpenSSL to clear the per-thread error
queue. Instead, clear the entire per-thread queue ahead of certain I/O
operations when it appears that there might be trouble (these I/O
operations mostly need to call SSL_get_error() to check for success,
which relies on the queue being empty). This is slightly aggressive,
but it's pretty clear that the other callers have a very dubious claim
to ownership of the per-thread queue. Do this is both frontend and
backend code.
Finally, be more careful about clearing our own error queue, so as to
not cause these problems ourself. It's possibly that control previously
did not always reach SSLerrmessage(), where ERR_get_error() was supposed
to be called to clear the queue's earliest code. Make sure
ERR_get_error() is always called, so as to spare other users of OpenSSL
the possibility of similar problems caused by libpq (as opposed to
problems caused by a third party OpenSSL library like PHP's OpenSSL
extension). Again, do this is both frontend and backend code.
See bug #12799 and https://bugs.php.net/bug.php?id=68276
Based on patches by Dave Vitek and Peter Eisentraut.
Tom Lane [Fri, 6 May 2016 16:09:20 +0000 (12:09 -0400)]
Fix possible read past end of string in to_timestamp().
to_timestamp() handles the TH/th format codes by advancing over two input
characters, whatever those are. It failed to notice whether there were
two characters available to be skipped, making it possible to advance
the pointer past the end of the input string and keep on parsing.
A similar risk existed in the handling of "Y,YYY" format: it would advance
over three characters after the "," whether or not three characters were
available.
In principle this might be exploitable to disclose contents of server
memory. But the security team concluded that it would be very hard to use
that way, because the parsing loop would stop upon hitting any zero byte,
and TH/th format codes can't be consecutive --- they have to follow some
other format code, which would have to match whatever data is there.
So it seems impractical to examine memory very much beyond the end of the
input string via this bug; and the input string will always be in local
memory not in disk buffers, making it unlikely that anything very
interesting is close to it in a predictable way. So this doesn't quite
rise to the level of needing a CVE.
Tom Lane [Fri, 6 May 2016 00:08:58 +0000 (20:08 -0400)]
Update time zone data files to tzdata release 2016d.
DST law changes in Russia (Magadan, Tomsk regions) and Venezuela.
Historical corrections for Russia. There are new zone names Europe/Kirov
and Asia/Tomsk reflecting the fact that these regions now have different
time zone histories from adjacent regions.
Tom Lane [Mon, 2 May 2016 15:18:11 +0000 (11:18 -0400)]
Fix configure's incorrect version tests for flex and perl.
awk's equality-comparison operator is "==" not "=". We got this right
in many places, but not in configure's checks for supported version
numbers of flex and perl. It hadn't been noticed because unsupported
versions are so old as to be basically extinct in the wild, and because
the only consequence is whether or not a WARNING flies by during
configure.
Daniel Gustafsson noted the problem with respect to the test for flex,
I found the other by reviewing other awk calls.
CHECK_PAGE_OFFSET_RANGE() has been unused forever.
CHECK_RELATION_BLOCK_RANGE() has been unused in pgstatindex.c ever since
bt_page_stats() and bt_page_items() functions were moved from pgstattuple
to pageinspect module. It still exists in pageinspect/btreefuncs.c.
Tom Lane [Sat, 30 Apr 2016 00:19:38 +0000 (20:19 -0400)]
Fix mishandling of equivalence-class tests in parameterized plans.
Given a three-or-more-way equivalence class, such as X.Y = Y.Y = Z.Z,
it was possible for the planner to omit one of the quals needed to
enforce that all members of the equivalence class are actually equal.
This only happened in the case of a parameterized join node for two
of the relations, that is a plan tree like
Nested Loop
-> Scan X
-> Nested Loop
-> Scan Y
-> Scan Z
Filter: Z.Z = X.X
The eclass machinery normally expects to apply X.X = Y.Y when those
two relations are joined, but in this shape of plan tree they aren't
joined until the top node --- and, if the lower nested loop is marked
as parameterized by X, the top node will assume that the relevant eclass
condition(s) got pushed down into the lower node. On the other hand,
the scan of Z assumes that it's only responsible for constraining Z.Z
to match any one of the other eclass members. So one or another of
the required quals sometimes fell between the cracks, depending on
whether consideration of the eclass in get_joinrel_parampathinfo()
for the lower nested loop chanced to generate X.X = Y.Y or X.X = Z.Z
as the appropriate constraint there. If it generated the latter,
it'd erroneously suppose that the Z scan would take care of matters.
To fix, force X.X = Y.Y to be generated and applied at that join node
when this case occurs.
This is *extremely* hard to hit in practice, because various planner
behaviors conspire to mask the problem; starting with the fact that the
planner doesn't really like to generate a parameterized plan of the
above shape. (It might have been impossible to hit it before we
tweaked things to allow this plan shape for star-schema cases.) Many
thanks to Alexander Kirkouski for submitting a reproducible test case.
The bug can be demonstrated in all branches back to 9.2 where parameterized
paths were introduced, so back-patch that far.
Tom Lane [Thu, 28 Apr 2016 15:50:58 +0000 (11:50 -0400)]
Adjust DatumGetBool macro, this time for sure.
Commit 23a41573c attempted to fix the DatumGetBool macro to ignore bits
in a Datum that are to the left of the actual bool value. But it did that
by casting the Datum to bool; and on compilers that use C99 semantics for
bool, that ends up being a whole-word test, not a 1-byte test. This seems
to be the true explanation for contrib/seg failing in VS2015. To fix, use
GET_1_BYTE() explicitly. I think in the previous patch, I'd had some idea
of not having to commit to bool being exactly 1 byte wide, but regardless
of what the compiler's bool is, boolean columns and Datums are certainly
1 byte wide.
The previous fix was (eventually) back-patched into all active versions,
so do likewise with this one.