Commit Graph

39307 Commits

Author SHA1 Message Date
Simon Riggs
c479024d32 Correct StartupSUBTRANS for page wraparound
StartupSUBTRANS() incorrectly handled cases near the max pageid in the subtrans
data structure, which in some cases could lead to errors in startup for Hot
Standby.
This patch wraps the pageids correctly, avoiding any such errors.
Identified by exhaustive crash testing by Jeff Janes.

Jeff Janes
2016-02-19 08:31:39 +00:00
Bruce Momjian
6f43c4d348 pg_upgrade: suppress creation of delete script
Suppress creation of the pg_upgrade delete script when the new data
directory is inside the old data directory.

Reported-by: IRC

Backpatch-through: 9.3, where delete script tests were added
2016-02-18 18:32:26 -05:00
Tom Lane
0276bbd623 Fix multiple bugs in contrib/pgstattuple's pgstatindex() function.
Dead or half-dead index leaf pages were incorrectly reported as live, as a
consequence of a code rearrangement I made (during a moment of severe brain
fade, evidently) in commit d287818eb5.

The index metapage was not counted in index_size, causing that result to
not agree with the actual index size on-disk.

Index root pages were not counted in internal_pages, which is inconsistent
compared to the case of a root that's also a leaf (one-page index), where
the root would be counted in leaf_pages.  Aside from that inconsistency,
this could lead to additional transient discrepancies between the reported
page counts and index_size, since it's possible for pgstatindex's scan to
see zero or multiple pages marked as BTP_ROOT, if the root moves due to
a split during the scan.  With these fixes, index_size will always be
exactly one page more than the sum of the displayed page counts.

Also, the index_size result was incorrectly documented as being measured in
pages; it's always been measured in bytes.  (While fixing that, I couldn't
resist doing some small additional wordsmithing on the pgstattuple docs.)

Including the metapage causes the reported index_size to not be zero for
an empty index.  To preserve the desired property that the pgstattuple
regression test results are platform-independent (ie, BLCKSZ configuration
independent), scale the index_size result in the regression tests.

The documentation issue was reported by Otsuka Kenji, and the inconsistent
root page counting by Peter Geoghegan; the other problems noted by me.
Back-patch to all supported branches, because this has been broken for
a long time.
2016-02-18 15:40:35 -05:00
Tom Lane
2ce19f8a57 Make plpython cope with funny characters in function names.
A function name that's double-quoted in SQL can contain almost any
characters, but we were using that name directly as part of the name
generated for the Python-level function, and Python doesn't like
anything that isn't pretty much a standard identifier.  To fix,
replace anything that isn't an ASCII letter or digit with an underscore
in the generated name.  This doesn't create any risk of duplicate Python
function names because we were already appending the function OID to
the generated name to ensure uniqueness.  Per bug #13960 from Jim Nasby.

Patch by Jim Nasby, modified a bit by me.  Back-patch to all
supported branches.
2016-02-16 21:08:15 -05:00
Tom Lane
6ce8236ff4 Improve documentation about CREATE INDEX CONCURRENTLY.
Clarify the description of which transactions will block a CREATE INDEX
CONCURRENTLY command from proceeding, and mention that the index might
still not be usable after CREATE INDEX completes.  (This happens if the
index build detected broken HOT chains, so that pg_index.indcheckxmin gets
set, and there are open old transactions preventing the xmin horizon from
advancing past the index's initial creation.  I didn't want to explain what
broken HOT chains are, though, so I omitted an explanation of exactly when
old transactions prevent the index from being used.)

Per discussion with Chris Travers.  Back-patch to all supported branches,
since the same text appears in all of them.
2016-02-16 13:43:26 -05:00
Bruce Momjian
3970b510ad release notes: fix 9.5 SGML comment about commit
Reported-by: Tatsuo Ishii

Backpatch-through: 9.5
2016-02-16 12:43:08 -05:00
Tatsuo Ishii
ce18d6bd30 Improve wording in the planner doc
Change "In this case" to "In the example above" to clarify what it
actually refers to.
2016-02-16 15:36:52 +09:00
Fujii Masao
177ff78ddb Correct the formulas for System V IPC parameters SEMMNI and SEMMNS in docs.
In runtime.sgml, the old formulas for calculating the reasonable
values of SEMMNI and SEMMNS were incorrect. They have forgotten to
count the number of semaphores which both the checkpointer process
(introduced in 9.2) and the background worker processes (introduced
in 9.3) need.

This commit fixes those formulas so that they count the number of
semaphores which the checkpointer process and the background worker
processes need.

Report and patch by Kyotaro Horiguchi. Only the patch for 9.3 was
modified by me. Back-patch to 9.2 where the checkpointer process was
added and the number of needed semaphores was increased.

Author: Kyotaro Horiguchi
Reviewed-by: Fujii Masao
Backpatch: 9.2
Discussion: http://www.postgresql.org/message-id/20160203.125119.66820697.horiguchi.kyotaro@lab.ntt.co.jp
2016-02-16 14:58:09 +09:00
Joe Conway
73ca21c7ac Move DATA entry to correct position
In commit 7b4bfc87 the DATA and DESCR entries for the new
row_security_active() function were inadvertantly put after
the PROVOLATILE defines, rather than before as they should
have been placed. Move them up where they belong.

Backpatch to 9.5 where the new entries were introduced.
2016-02-15 16:37:16 -08:00
Alvaro Herrera
1bad289a80 pgbench: avoid FD_ISSET on an invalid file descriptor
The original code wasn't careful to test the file descriptor returned by
PQsocket() for an invalid socket.  If an invalid socket did turn up,
that would amount to calling FD_ISSET with fd = -1, whereby undefined
behavior can be invoked.

To fix, test file descriptor for validity and stop further processing if
that fails.

Problem noticed by Coverity.

There is an existing FD_ISSET callsite that does check for invalid
sockets beforehand, but the error message reported by it was
strerror(errno); in testing the aforementioned change, that turns out to
result in "bad socket: Success" which isn't terribly helpful.  Instead
use PQerrorMessage() in both places which is more likely to contain an
useful error message.

Backpatch-through: 9.1.
2016-02-15 20:33:43 -03:00
Tom Lane
d2ab9b0ac3 Suppress compiler warnings about useless comparison of unsigned to zero.
Reportedly, some compilers warn about tests like "c < 0" if c is unsigned,
and hence complain about the character range checks I added in commit
3bb3f42f37.  This is a bit of a pain since
the regex library doesn't really want to assume that chr is unsigned.
However, since any such reconfiguration would involve manual edits of
regcustom.h anyway, we can put it on the shoulders of whoever wants to
do that to adjust this new range-checking macro correctly.

Per gripes from Coverity and Andres.
2016-02-15 17:11:52 -05:00
Noah Misch
2dcaebea07 In pg_rewind test suite, triple promote timeout to 90s.
Thirty seconds was not consistently enough for promotion to complete on
buildfarm members sungazer and tern.  Experiments suggest 43s would have
been enough.  Back-patch to 9.5, where pg_rewind was introduced.
2016-02-10 20:36:21 -05:00
Noah Misch
725f0ce296 Accept pg_ctl timeout from the PGCTLTIMEOUT environment variable.
Many automated test suites call pg_ctl.  Buildfarm members axolotl,
hornet, mandrill, shearwater, sungazer and tern have failed when server
shutdown took longer than the pg_ctl default 60s timeout.  This addition
permits slow hosts to easily raise the timeout without us editing a
--timeout argument into every test suite pg_ctl call.  Back-patch to 9.1
(all supported versions) for the sake of automated testing.

Reviewed by Tom Lane.
2016-02-10 20:34:24 -05:00
Tom Lane
b10635bb5b Avoid use of sscanf() to parse ispell dictionary files.
It turns out that on FreeBSD-derived platforms (including OS X), the
*scanf() family of functions is pretty much brain-dead about multibyte
characters.  In particular it will apply isspace() to individual bytes
of input even when those bytes are part of a multibyte character, thus
allowing false recognition of a field-terminating space.

We appear to have little alternative other than instituting a coding
rule that *scanf() is not to be used if the input string might contain
multibyte characters.  (There was some discussion of relying on "%ls",
but that probably just moves the portability problem somewhere else,
and besides it doesn't fully prevent BSD *scanf() from using isspace().)

This patch is a down payment on that: it gets rid of use of sscanf()
to parse ispell dictionary files, which are certainly at great risk
of having a problem.  The code is cleaner this way anyway, though
a bit longer.

In passing, improve a few comments.

Report and patch by Artur Zakirov, reviewed and somewhat tweaked by me.
Back-patch to all supported branches.
2016-02-10 19:30:11 -05:00
Tom Lane
616eaa396a Stamp 9.5.1. 2016-02-08 16:12:28 -05:00
Peter Eisentraut
477bee7dc6 Translation updates
Source-Git-URL: git://git.postgresql.org/git/pgtranslation/messages.git
Source-Git-Hash: f323fead9293175a0c3320116c97e4be56b9be61
2016-02-08 14:21:00 -05:00
Tom Lane
129b6cf5eb Last-minute updates for release notes.
Security: CVE-2016-0773
2016-02-08 10:49:37 -05:00
Tom Lane
a61de2bc13 Fix some regex issues with out-of-range characters and large char ranges.
Previously, our regex code defined CHR_MAX as 0xfffffffe, which is a
bad choice because it is outside the range of type "celt" (int32).
Characters approaching that limit could lead to infinite loops in logic
such as "for (c = a; c <= b; c++)" where c is of type celt but the
range bounds are chr.  Such loops will work safely only if CHR_MAX+1
is representable in celt, since c must advance to beyond b before the
loop will exit.

Fortunately, there seems no reason not to restrict CHR_MAX to 0x7ffffffe.
It's highly unlikely that Unicode will ever assign codes that high, and
none of our other backend encodings need characters beyond that either.

In addition to modifying the macro, we have to explicitly enforce character
range restrictions on the values of \u, \U, and \x escape sequences, else
the limit is trivially bypassed.

Also, the code for expanding case-independent character ranges in bracket
expressions had a potential integer overflow in its calculation of the
number of characters it could generate, which could lead to allocating too
small a character vector and then overwriting memory.  An attacker with the
ability to supply arbitrary regex patterns could easily cause transient DOS
via server crashes, and the possibility for privilege escalation has not
been ruled out.

Quite aside from the integer-overflow problem, the range expansion code was
unnecessarily inefficient in that it always produced a result consisting of
individual characters, abandoning the knowledge that we had a range to
start with.  If the input range is large, this requires excessive memory.
Change it so that the original range is reported as-is, and then we add on
any case-equivalent characters that are outside that range.  With this
approach, we can bound the number of individual characters allowed without
sacrificing much.  This patch allows at most 100000 individual characters,
which I believe to be more than the number of case pairs existing in
Unicode, so that the restriction will never be hit in practice.

It's still possible for range() to take awhile given a large character code
range, so also add statement-cancel detection to its loop.  The downstream
function dovec() also lacked cancel detection, and could take a long time
given a large output from range().

Per fuzz testing by Greg Stark.  Back-patch to all supported branches.

Security: CVE-2016-0773
2016-02-08 10:25:40 -05:00
Andres Freund
87dbc72a79 Fix overeager pushdown of HAVING clauses when grouping sets are used.
In 61444bfb we started to allow HAVING clauses to be fully pushed down
into WHERE, even when grouping sets are in use. That turns out not to
work correctly, because grouping sets can "produce" NULLs, meaning that
filtering in WHERE and HAVING can have different results, even when no
aggregates or volatile functions are involved.

Instead only allow pushdown of empty grouping sets.

It'd be nice to do better, but the exact mechanics of deciding which
cases are safe are still being debated. It's important to give correct
results till we find a good solution, and such a solution might not be
appropriate for backpatching anyway.

Bug: #13863
Reported-By: 'wrb'
Diagnosed-By: Dean Rasheed
Author: Andrew Gierth
Reviewed-By: Dean Rasheed and Andres Freund
Discussion: 20160113183558.12989.56904@wrigleys.postgresql.org
Backpatch: 9.5, where grouping sets were introduced
2016-02-08 11:03:37 +01:00
Tom Lane
65f1510a82 Improve documentation about PRIMARY KEY constraints.
Get rid of the false implication that PRIMARY KEY is exactly equivalent to
UNIQUE + NOT NULL.  That was more-or-less true at one time in our
implementation, but the standard doesn't say that, and we've grown various
features (many of them required by spec) that treat a pkey differently from
less-formal constraints.  Per recent discussion on pgsql-general.

I failed to resist the temptation to do some other wordsmithing in the
same area.
2016-02-07 16:02:44 -05:00
Tom Lane
82406d6ff1 Fix deparsing of ON CONFLICT arbiter WHERE clauses.
The parser doesn't allow qualification of column names appearing in
these clauses, but ruleutils.c would sometimes qualify them, leading
to dump/reload failures.  Per bug #13891 from Onder Kalaci.

(In passing, make stanzas in ruleutils.c that save/restore varprefix
more consistent.)

Peter Geoghegan
2016-02-07 14:57:24 -05:00
Tom Lane
bd0302c39d Release notes for 9.5.1, 9.4.6, 9.3.11, 9.2.15, 9.1.20. 2016-02-07 14:16:31 -05:00
Tom Lane
129db3cbee ExecHashRemoveNextSkewBucket must physically copy tuples to main hashtable.
Commit 45f6240a8f added an assumption in ExecHashIncreaseNumBatches
and ExecHashIncreaseNumBuckets that they could find all tuples in the main
hash table by iterating over the "dense storage" introduced by that patch.
However, ExecHashRemoveNextSkewBucket continued its old practice of simply
re-linking deleted skew tuples into the main table's hashchains.  Hence,
such tuples got lost during any subsequent increase in nbatch or nbuckets,
and would never get joined, as reported in bug #13908 from Seth P.

I (tgl) think that the aforesaid commit has got multiple design issues
and should be reworked rather completely; but there is no time for that
right now, so band-aid the problem by making ExecHashRemoveNextSkewBucket
physically copy deleted skew tuples into the "dense storage" arena.

The added test case is able to exhibit the problem by means of fooling the
planner with a WHERE condition that it will underestimate the selectivity
of, causing the initial nbatch estimate to be too small.

Tomas Vondra and Tom Lane.  Thanks to David Johnston for initial
investigation into the bug report.
2016-02-07 12:29:17 -05:00
Tom Lane
2b94b5ef8d Improve HJDEBUG code a bit.
Commit 30d7ae3c76 introduced an HJDEBUG
stanza that probably didn't compile at the time, and definitely doesn't
compile now, because it refers to a nonexistent variable.  It doesn't seem
terribly useful anyway, so just get rid of it.

While I'm fooling with it, use %z modifier instead of the obsolete hack of
casting size_t to unsigned long, and include the HashJoinTable's address in
each printout so that it's possible to distinguish the activities of
multiple hashjoins occurring in one query.

Noted while trying to use HJDEBUG to investigate bug #13908.  Back-patch
to 9.5, because code that doesn't compile is certainly not very helpful.
2016-02-06 15:05:23 -05:00
Noah Misch
0089dd34aa Force certain "pljava" custom GUCs to be PGC_SUSET.
Future PL/Java versions will close CVE-2016-0766 by making these GUCs
PGC_SUSET.  This PostgreSQL change independently mitigates that PL/Java
vulnerability, helping sites that update PostgreSQL more frequently than
PL/Java.  Back-patch to 9.1 (all supported versions).
2016-02-05 20:23:04 -05:00
Tom Lane
37e6946329 Update time zone data files to tzdata release 2016a.
DST law changes in Cayman Islands, Metlakatla, Trans-Baikal Territory
(Zabaykalsky Krai).  Historical corrections for Pakistan.
2016-02-05 10:59:21 -05:00
Robert Haas
d160e2a343 postgres_fdw: Avoid possible misbehavior when RETURNING tableoid column only.
deparseReturningList ended up adding up RETURNING NULL to the code, but
code elsewhere saw an empty list of attributes and concluded that it
should not expect tuples from the remote side.

Etsuro Fujita and Robert Haas, reviewed by Thom Brown
2016-02-04 22:27:38 -05:00
Robert Haas
453d40817c When modifying a foreign table, initialize tableoid field properly.
Failure to do this can cause AFTER ROW triggers or RETURNING expressions
that reference this field to misbehave.

Etsuro Fujita, reviewed by Thom Brown
2016-02-04 21:17:46 -05:00
Tom Lane
3676136ffc Simplify syntax diagram for REINDEX.
Since there currently is only one possible parenthesized option, namely
VERBOSE, it's a bit pointless to show it with "{ } [, ... ]".  The curly
braces are useless and therefore confusing, as seen in a recent question
from Karsten Hilbert.  Remove the extra decoration for the time being;
we can put it back when and if REINDEX grows some more options.
2016-02-04 13:58:52 -05:00
Tom Lane
b99dd71705 In pg_dump, ensure that view triggers are processed after view rules.
If a view is split into CREATE TABLE + CREATE RULE to break a circular
dependency, then any triggers on the view must be dumped/reloaded after
the CREATE RULE; else the backend may reject the CREATE TRIGGER because
it's the wrong type of trigger for a plain table.  This works all right
in plain dump/restore because of pg_dump's sorting heuristic that places
triggers after rules.  However, when using parallel restore, the ordering
must be enforced by a dependency --- and we didn't have one.

Fixing this is a mere matter of adding an addObjectDependency() call,
except that we need to be able to find all the triggers belonging to the
view relation, and there was no easy way to do that.  Add fields to
pg_dump's TableInfo struct to remember where the associated TriggerInfo
struct(s) are.

Per bug report from Dennis Kögel.  The failure can be exhibited at least
as far back as 9.1, so back-patch to all supported branches.
2016-02-04 00:26:10 -05:00
Tom Lane
b523a5c0e5 Add hstore_to_jsonb() and hstore_to_jsonb_loose() to hstore documentation.
These were never documented anywhere user-visible.  Tut tut.
2016-02-03 12:56:40 -05:00
Tom Lane
1c291624b2 Fix IsValidJsonNumber() to notice trailing non-alphanumeric garbage.
Commit e09996ff8d was one brick shy of a load: it didn't insist
that the detected JSON number be the whole of the supplied string.
This allowed inputs such as "2016-01-01" to be misdetected as valid JSON
numbers.  Per bug #13906 from Dmitry Ryabov.

In passing, be more wary of zero-length input (I'm not sure this can
happen given current callers, but better safe than sorry), and do some
minor cosmetic cleanup.
2016-02-03 01:39:08 -05:00
Tom Lane
f39c927114 Fix pg_description entries for jsonb_to_record() and jsonb_to_recordset().
All the other jsonb function descriptions refer to the arguments as being
"jsonb", but these two said "json".  Make it consistent.  Per bug #13905
from Petru Florin Mihancea.

No catversion bump --- we can't force one in the back branches, and this
isn't very critical anyway.
2016-02-02 11:39:50 -05:00
Magnus Hagander
081f7fe110 Fix typo in comment 2016-02-02 13:49:20 +01:00
Teodor Sigaev
62e0ade9aa Fix lossy KNN GiST when ordering operator returns non-float8 value.
KNN GiST with recheck flag should return to executor the same type as ordering
operator, GiST detects this type by looking to return type of function which
implements ordering operator. But occasionally detecting code works after
replacing ordering operator function to distance support function.
Distance support function always returns float8, so, detecting code get float8
instead of actual return type of ordering operator.

Built-in opclasses don't have ordering operator which doesn't return
non-float8 value, so, tests are impossible here, at least now.

Backpatch to 9.5 where lozzy KNN was introduced.

Author: Alexander Korotkov
Report by: Artur Zakirov
2016-02-02 15:21:03 +03:00
Robert Haas
829757c8a2 pgbench: Install guards against obscure overflow conditions.
Dividing INT_MIN by -1 or taking INT_MIN modulo -1 can sometimes
cause floating-point exceptions or otherwise misbehave.

Fabien Coelho and Michael Paquier
2016-02-01 08:26:07 -05:00
Michael Meskes
40482e6067 Make sure ecpg header files do not have a comment lasting several lines, one of
which is a preprocessor directive. This leads ecpg to incorrectly parse the comment as nested.
2016-02-01 13:20:37 +01:00
Heikki Linnakangas
6ceca3f4a2 Fix misspelled function name in comment. 2016-02-01 10:10:54 +02:00
Andrew Dunstan
a16763d892 Fix error in documentated use of mingw-w64 compilers
Error reported by Igal Sapir.
2016-01-30 19:30:59 -05:00
Tom Lane
56251f3965 Fix incorrect pattern-match processing in psql's \det command.
listForeignTables' invocation of processSQLNamePattern did not match up
with the other ones that handle potentially-schema-qualified names; it
failed to make use of pg_table_is_visible() and also passed the name
arguments in the wrong order.  Bug seems to have been aboriginal in commit
0d692a0dc9.  It accidentally sort of worked as long as you didn't
inquire too closely into the behavior, although the silliness was later
exposed by inconsistencies in the test queries added by 59efda3e50
(which I probably should have questioned at the time, but didn't).

Per bug #13899 from Reece Hart.  Patch by Reece Hart and Tom Lane.
Back-patch to all affected branches.
2016-01-29 10:28:02 +01:00
Fujii Masao
cb89a3afaa Fix syntax descriptions for replication commands in logicaldecoding.sgml
Patch-by: Oleksandr Shulgin
Reviewed-by: Craig Ringer and Fujii Masao
Backpatch-through: 9.4 where logical decoding was introduced
2016-01-29 12:15:34 +09:00
Robert Haas
db58a95931 Add [NO]BYPASSRLS options to CREATE USER and ALTER USER docs.
Patch-by: Filip Rembiałkowski
Reviewed-by: Robert Haas
Backpatch-through: 9.5
2016-01-28 09:33:20 -05:00
Alvaro Herrera
950beba003 Fix spi_worker mention in bgworker documentation
The documentation mentioned contrib/ but the module was moved to
src/test/modules/ by commit 22dfd116a1 of 9.5 era.

Problem pointed out by Dickson Guedes in bug #13896
Backpatch-to: 9.5.
2016-01-28 14:08:21 +01:00
Tom Lane
2acb682f68 Fix startup so that log prefix %h works for the log_connections message.
We entirely randomly chose to initialize port->remote_host just after
printing the log_connections message, when we could perfectly well do it
just before, allowing %h and %r to work for that message.  Per gripe from
Artem Tomyuk.
2016-01-26 15:38:33 -05:00
Tatsuo Ishii
e8267aba5f Revert "Fix broken multibyte regression tests."
This reverts commit 479cb1e420.

The commit was plain wrong as pointed out in:
http://www.postgresql.org/message-id/27771.1448736909@sss.pgh.pa.us
2016-01-26 09:00:33 +09:00
Alvaro Herrera
1e910cf5ba pg_dump: Fix quoting of domain constraint names
The original code was adding double quotes to an already-quoted
identifier, leading to nonsensical results.  Remove the quoting call.

I introduced the broken code in 7eca575d1c of 9.5 era, so backpatch to
9.5.

Report and patch by Elvis Pranskevichus
Reviewed by Michael Paquier
2016-01-22 20:04:35 -03:00
Tom Lane
042a3e2353 Improve levenshtein() docs.
Fix chars-vs-bytes confusion here too.  Improve poor grammar and
markup.
2016-01-22 12:29:22 -05:00
Tom Lane
47acf3add3 Remove new coupling between NAMEDATALEN and MAX_LEVENSHTEIN_STRLEN.
Commit e529cd4ffa introduced an Assert requiring NAMEDATALEN to be
less than MAX_LEVENSHTEIN_STRLEN, which has been 255 for a long time.
Since up to that instant we had always allowed NAMEDATALEN to be
substantially more than that, this was ill-advised.

It's debatable whether we need MAX_LEVENSHTEIN_STRLEN at all (versus
putting a CHECK_FOR_INTERRUPTS into the loop), or whether it has to be
so tight; but this patch takes the narrower approach of just not applying
the MAX_LEVENSHTEIN_STRLEN limit to calls from the parser.

Trusting the parser for this seems reasonable, first because the strings
are limited to NAMEDATALEN which is unlikely to be hugely more than 256,
and second because the maximum distance is tightly constrained by
MAX_FUZZY_DISTANCE (though we'd forgotten to make use of that limit in one
place).  That means the cost is not really O(mn) but more like O(max(m,n)).

Relaxing the limit for user-supplied calls is left for future research;
given the lack of complaints to date, it doesn't seem very high priority.

In passing, fix confusion between lengths-in-bytes and lengths-in-chars
in comments and error messages.

Per gripe from Kevin Day; solution suggested by Robert Haas.  Back-patch
to 9.5 where the unwanted restriction was introduced.
2016-01-22 11:53:06 -05:00
Tom Lane
e80c85e4e8 Add defenses against putting expanded objects into Const nodes.
Putting a reference to an expanded-format value into a Const node would be
a bad idea for a couple of reasons.  It'd be possible for the supposedly
immutable Const to change value, if something modified the referenced
variable ... in fact, if the Const's reference were R/W, any function that
has the Const as argument might itself change it at runtime.  Also, because
datumIsEqual() is pretty simplistic, the Const might fail to compare equal
to other Consts that it should compare equal to, notably including copies
of itself.  This could lead to unexpected planner behavior, such as "could
not find pathkey item to sort" errors or inferior plans.

I have not been able to find any way to get an expanded value into a Const
within the existing core code; but Paul Ramsey was able to trigger the
problem by writing a datatype input function that returns an expanded
value.

The best fix seems to be to establish a rule that varlena values being
placed into Const nodes should be passed through pg_detoast_datum().
That will do nothing (and cost little) in normal cases, but it will flatten
expanded values and thereby avoid the above problems.  Also, it will
convert short-header or compressed values into canonical format, which will
avoid possible unexpected lack-of-equality issues for those cases too.
And it provides a last-ditch defense against putting a toasted value into
a Const, which we already knew was dangerous, cf commit 2b0c86b665.
(In the light of this discussion, I'm no longer sure that that commit
provided 100% protection against such cases, but this fix should do it.)

The test added in commit 65c3d05e18 to catch datatype input functions
with unstable results would fail for functions that returned expanded
values; but it seems a bit uncharitable to deem a result unstable just
because it's expressed in expanded form, so revise the coding so that we
check for bitwise equality only after applying pg_detoast_datum().  That's
a sufficient condition anyway given the new rule about detoasting when
forming a Const.

Back-patch to 9.5 where the expanded-object facility was added.  It's
possible that this should go back further; but in the absence of clear
evidence that there's any live bug in older branches, I'll refrain for now.
2016-01-21 12:55:59 -05:00
Bruce Momjian
34bda20ae5 Properly install dynloader.h on MSVC builds
This will enable PL/Java to be cleanly compiled, as dynloader.h is a
requirement.

Report by Chapman Flack

Patch by Michael Paquier

Backpatch through 9.1
2016-01-19 23:30:29 -05:00