This function formerly crashed if called as a statement-level trigger,
or if a column-name argument wasn't given.
In passing, add the trigger name to all error messages from the function.
(None of them are expected cases, so this shouldn't pose any compatibility
risk.)
Marc Cousin, reviewed by Sawada Masahiko
The previous coding labeled expressions such as pg_index.indkey[1:3] as
being of int2vector type; which is not right because the subscript bounds
of such a result don't, in general, satisfy the restrictions of int2vector.
To fix, implicitly promote the result of slicing int2vector to int2[],
or oidvector to oid[]. This is similar to what we've done with domains
over arrays, which is a good analogy because these types are very much
like restricted domains of the corresponding regular-array types.
A side-effect is that we now also forbid array-element updates on such
columns, eg while "update pg_index set indkey[4] = 42" would have worked
before if you were superuser (and corrupted your catalogs irretrievably,
no doubt) it's now disallowed. This seems like a good thing since, again,
some choices of subscripting would've led to results not satisfying the
restrictions of int2vector. The case of an array-slice update was
rejected before, though with a different error message than you get now.
We could make these cases work in future if we added a cast from int2[]
to int2vector (with a cast function checking the subscript restrictions)
but it seems unlikely that there's any value in that.
Per report from Ronan Dunklau. Back-patch to all supported branches
because of the crash risks involved.
If logging is enabled, either ereport() or fprintf() might stomp on errno
internally, causing this function to return the wrong result. That might
only end in a misleading error report, but in any code that's examining
errno to decide what to do next, the consequences could be far graver.
This has been broken since the very first version of this file in 2006
... it's a bit astonishing that we didn't identify this long ago.
Reported by Amit Kapila, though this isn't his proposed fix.
A pointer to a C string was treated as a pointer to a "name" datum and
passed to SPI_execute_plan(). This pointer would then end up being
passed through datumCopy(), which would try to copy the entire 64 bytes
of name data, thus running past the end of the C string. Fix by
converting the string to a proper name structure.
Found by LLVM AddressSanitizer.
pullup_replace_vars()'s decisions about whether a pulled-up replacement
expression needs to be wrapped in a PlaceHolderVar depend on the assumption
that what looks like a Var behaves like a Var. However, if the Var is a
join alias reference, later flattening of join aliases might replace the
Var with something that's not a Var at all, and should have been wrapped.
To fix, do a forcible pass of flatten_join_alias_vars() on the subquery
targetlist before we start to copy items out of it. We'll re-run that
processing on the pulled-up expressions later, but that's harmless.
Per report from Ken Tanzer; the added regression test case is based on his
example. This bug has been there since the PlaceHolderVar mechanism was
invented, but has escaped detection because the circumstances that trigger
it are fairly narrow. You need a flattenable query underneath an outer
join, which contains another flattenable query inside a join of its own,
with a dangerous expression (a constant or something else non-strict)
in that one's targetlist.
Having seen this, I'm wondering if it wouldn't be prudent to do all
alias-variable flattening earlier, perhaps even in the rewriter.
But that would probably not be a back-patchable change.
A couple of places that should have been iterating over WORDS_PER_CHUNK
words were iterating over WORDS_PER_PAGE words instead. This thinko
accidentally failed to fail, because (at least on common architectures
with default BLCKSZ) WORDS_PER_CHUNK is a bit less than WORDS_PER_PAGE,
and the extra words being looked at were always zero so nothing happened.
Still, it's a bug waiting to happen if anybody ever fools with the
parameters affecting TIDBitmap sizes, and it's a small waste of cycles
too. So back-patch to all active branches.
Etsuro Fujita
If a page is deleted, and reused for something else, just as a search is
following a rightlink to it from its left sibling, the search would continue
scanning whatever the new contents of the page are. That could lead to
incorrect query results, or even something more curious if the page is
reused for a different kind of a page.
To fix, modify the search algorithm to lock the next page before releasing
the previous one, and refrain from deleting pages from the leftmost branch
of the tree.
Add a new Concurrency section to the README, explaining why this works.
There is a lot more one could say about concurrency in GIN, but that's for
another patch.
Backpatch to all supported versions.
This change prevents us from doing inappropriate subquery flattening in
cases such as dangerous functions hidden inside a sub-SELECT in the
targetlist of another sub-SELECT. That could result in unexpected behavior
due to multiple evaluations of a volatile function, as in a recent
complaint from Etienne Dube. It's been questionable from the very
beginning whether these functions should look into subqueries (as noted in
their comments), and this case seems to provide proof that they should.
Because the new code only descends into SubLinks, not SubPlans or
InitPlans, the change only affects the planner's behavior during
prepjointree processing and not later on --- for example, you can still get
it to use a volatile function in an indexqual if you wrap the function in
(SELECT ...). That's a historical behavior, for sure, but it's reasonable
given that the executor's evaluation rules for subplans don't depend on
whether there are volatile functions inside them. In any case, we need to
constrain the behavioral change as narrowly as we can to make this
reasonable to back-patch.
Back-patch commits 8e68816cc2 and
8dace66e07 into the stable branches.
Buildfarm testing revealed no great portability surprises, and it
seems useful to have this robustness improvement in all branches.
Insertion of default arguments doesn't work for window functions, which is
likely to cause a crash at runtime if the implementation code doesn't check
the number of actual arguments carefully. It doesn't seem worth working
harder than this for pre-9.2 branches.
For rather inscrutable reasons, SQL:2008 disallows copying-and-modifying a
window definition that has any explicit framing clause. The error message
we gave for this only made sense if the referencing window definition
itself contains an explicit framing clause, which it might well not.
Moreover, in the context of an OVER clause it's not exactly obvious that
"OVER (windowname)" implies copy-and-modify while "OVER windowname" does
not. This has led to multiple complaints, eg bug #5199 from Iliya
Krapchatov. Change to a hopefully more intelligible error message, and
in the case where we have just "OVER (windowname)", add a HINT suggesting
that omitting the parentheses will fix it. Also improve the related
documentation. Back-patch to all supported branches.
Callers expect that they only have to set the right resource owner when
creating a BufFile, not during subsequent operations on it. While we could
insist this be fixed at the caller level, it seems more sensible for the
BufFile to take care of it. Without this, some temp files belonging to
a BufFile can go away too soon, eg at the end of a subtransaction,
leading to errors or crashes.
Reported and fixed by Andres Freund. Back-patch to all active branches.
Formerly, when using a SQL-spec timezone setting with a fixed GMT offset
(called a "brute force" timezone in the code), the session_timezone
variable was not updated to match the nominal timezone; rather, all code
was expected to ignore session_timezone if HasCTZSet was true. This is
of course obviously fragile, though a search of the code finds only
timeofday() failing to honor the rule. A bigger problem was that
DetermineTimeZoneOffset() supposed that if its pg_tz parameter was
pointer-equal to session_timezone, then HasCTZSet should override the
parameter. This would cause datetime input containing an explicit zone
name to be treated as referencing the brute-force zone instead, if the
zone name happened to match the session timezone that had prevailed
before installing the brute-force zone setting (as reported in bug #8572).
The same malady could affect AT TIME ZONE operators.
To fix, set up session_timezone so that it matches the brute-force zone
specification, which we can do using the POSIX timezone definition syntax
"<abbrev>offset", and get rid of the bogus lookaside check in
DetermineTimeZoneOffset(). Aside from fixing the erroneous behavior in
datetime parsing and AT TIME ZONE, this will cause the timeofday() function
to print its result in the user-requested time zone rather than some
previously-set zone. It might also affect results in third-party
extensions, if there are any that make use of session_timezone without
considering HasCTZSet, but in all cases the new behavior should be saner
than before.
Back-patch to all supported branches.
The C and POSIX standards state that strncpy's behavior is undefined when
source and destination areas overlap. While it remains dubious whether any
implementations really misbehave when the pointers are exactly equal, some
platforms are now starting to force the issue by complaining when an
undefined call occurs. (In particular OS X 10.9 has been seen to dump core
here, though the exact set of circumstances needed to trigger that remain
elusive. Similar behavior can be expected to be optional on Linux and
other platforms in the near future.) So tweak the code to explicitly do
nothing when nothing need be done.
Back-patch to all active branches. In HEAD, this also lets us get rid of
an exception in valgrind.supp.
Per discussion of a report from Matthias Schmitt.
lo_open registers the currently active snapshot, and checks if the
large object exists after that. Normally, snapshots registered by lo_open
are unregistered at end of transaction when the lo descriptor is closed, but
if we error out before the lo descriptor is added to the list of open
descriptors, it is leaked. Fix by moving the snapshot registration to after
checking if the large object exists.
Reported by Pavel Stehule. Backpatch to 8.4. The snapshot registration
system was introduced in 8.4, so prior versions are not affected (and not
supported, anyway).
There is a rare race condition, when a transaction that inserted a tuple
aborts while vacuum is processing the page containing the inserted tuple.
Vacuum prunes the page first, which normally removes any dead tuples, but
if the inserting transaction aborts right after that, the loop after
pruning will see a dead tuple and remove it instead. That's OK, but if the
page is on a table with no indexes, and the page becomes completely empty
after removing the dead tuple (or tuples) on it, it will be immediately
marked as all-visible. That's OK, but the sanity check in vacuum would
throw a warning because it thinks that the page contains dead tuples and
was nevertheless marked as all-visible, even though it just vacuumed away
the dead tuples and so it doesn't actually contain any.
Spotted this while reading the code. It's difficult to hit the race
condition otherwise, but can be done by putting a breakpoint after the
heap_page_prune() call.
Backpatch all the way to 8.4, where this code first appeared.
In libpq, we set up and pass to OpenSSL callback routines to handle
locking. When we run out of SSL connections, we try to clean things
up by de-registering the hooks. Unfortunately, we had a few calls
into the OpenSSL library after these hooks were de-registered during
SSL cleanup which lead to deadlocking. This moves the thread callback
cleanup to be after all SSL-cleanup related OpenSSL library calls.
I've been unable to reproduce the deadlock with this fix.
In passing, also move the close_SSL call to be after unlocking our
ssl_config mutex when in a failure state. While it looks pretty
unlikely to be an issue, it could have resulted in deadlocks if we
ended up in this code path due to something other than SSL_new
failing. Thanks to Heikki for pointing this out.
Back-patch to all supported versions; note that the close_SSL issue
only goes back to 9.0, so that hunk isn't included in the 8.4 patch.
Initially found and reported by Vesa-Matti J Kari; many thanks to
both Heikki and Andres for their help running down the specific
issue and reviewing the patch.
Once the administrator has called for an immediate shutdown or a backend
crash has triggered a reinitialization, no mere SIGINT or SIGTERM should
change that course. Such derailment remains possible when the signal
arrives before quickdie() blocks signals. That being a narrow race
affecting most PostgreSQL signal handlers in some way, leave it for
another patch. Back-patch this to all supported versions.
The previous coding attempted to activate all the GUC settings specified
in SET clauses, so that the function validator could operate in the GUC
environment expected by the function body. However, this is problematic
when restoring a dump, since the SET clauses might refer to database
objects that don't exist yet. We already have the parameter
check_function_bodies that's meant to prevent forward references in
function definitions from breaking dumps, so let's change CREATE FUNCTION
to not install the SET values if check_function_bodies is off.
Authors of function validators were already advised not to make any
"context sensitive" checks when check_function_bodies is off, if indeed
they're checking anything at all in that mode. But extend the
documentation to point out the GUC issue in particular.
(Note that we still check the SET clauses to some extent; the behavior
with !check_function_bodies is now approximately equivalent to what ALTER
DATABASE/ROLE have been doing for awhile with context-dependent GUCs.)
This problem can be demonstrated in all active branches, so back-patch
all the way.
It's possible that inlining of SQL functions (or perhaps other changes?)
has exposed typmod information not known at parse time. In such cases,
Vars generated by query_planner might have valid typmod values while the
original grouping columns only have typmod -1. This isn't a semantic
problem since the behavior of grouping only depends on type not typmod,
but it breaks locate_grouping_columns' use of tlist_member to locate the
matching entry in query_planner's result tlist.
We can fix this without an excessive amount of new code or complexity by
relying on the fact that locate_grouping_columns only gets called when
make_subplanTargetList has set need_tlist_eval == false, and that can only
happen if all the grouping columns are simple Vars. Therefore we only need
to search the sub_tlist for a matching Var, and we can reasonably define a
"match" as being a match of the Var identity fields
varno/varattno/varlevelsup. The code still Asserts that vartype matches,
but ignores vartypmod.
Per bug #8393 from Evan Martin. The added regression test case is
basically the same as his example. This has been broken for a very long
time, so back-patch to all supported branches.
With this optimization flag enabled, recent versions of gcc can generate
incorrect code that assumes variable-length arrays (such as oidvector)
are actually fixed-length because they're embedded in some larger struct.
The known instance of this problem was fixed in 9.2 and up by commit
8137f2c323 and followon work, which hides
actually-variable-length catalog fields from the compiler altogether.
And we plan to gradually convert variable-length fields to official
"flexible array member" notation over time, which should prevent this type
of bug from reappearing as gcc gets smarter. We're not going to try to
back-port those changes into older branches, though, so apply this
band-aid instead.
Andres Freund
The C99 and POSIX standards require strtod() to accept all these spellings
(case-insensitively): "inf", "+inf", "-inf", "infinity", "+infinity",
"-infinity". However, pre-C99 systems might accept only some or none of
these, and apparently Windows still doesn't accept "inf". To avoid
surprising cross-platform behavioral differences, manually check for each
of these spellings if strtod() fails. We were previously handling just
"infinity" and "-infinity" that way, but since C99 is most of the world
now, it seems likely that applications are expecting all these spellings
to work.
Per bug #8355 from Basil Peace. It turns out this fix won't actually
resolve his problem, because Python isn't being this careful; but that
doesn't mean we shouldn't be.
If a tuple is locked but not updated by a concurrent transaction,
HeapTupleSatisfiesDirty would return that transaction's Xid in xmax,
causing callers to wait on it, when it is not necessary (in fact, if the
other transaction had used a multixact instead of a plain Xid to mark
the tuple, HeapTupleSatisfiesDirty would have behave differently and
*not* returned the Xmax).
This bug was introduced in commit 3f7fbf85dc, dated December 1998,
so it's almost 15 years old now. However, it's hard to see this
misbehave, because before we had NOWAIT the only consequence of this is
that transactions would wait for slightly more time than necessary; so
it's not surprising that this hasn't been reported yet.
Craig Ringer and Andres Freund
We'd find the same match twice if it was of zero length and not immediately
adjacent to the previous match. replace_text_regexp() got similar cases
right, so adjust this search logic to match that. Note that even though
the regexp_split_to_xxx() functions share this code, they did not display
equivalent misbehavior, because the second match would be considered
degenerate and ignored.
Jeevan Chalke, with some cosmetic changes by me.
These modules used the YYPARSE_PARAM macro, which has been deprecated
by the bison folk since 1.875, and which they finally removed in 3.0.
Adjust the code to use the replacement facility, %parse-param, which
is a much better solution anyway since it allows specification of the
type of the extra parser parameter. We can thus get rid of a lot of
unsightly casting.
Back-patch to all active branches, since somebody might try to build
a back branch with up-to-date tools.
In a boolean column that contains mostly nulls, ANALYZE might not find
enough non-null values to populate the most-common-values stats,
but it would still create a pg_statistic entry with stanullfrac set.
The logic in booltestsel() for this situation did the wrong thing for
"col IS NOT TRUE" and "col IS NOT FALSE" tests, forgetting that null
values would satisfy these tests (so that the true selectivity would
be close to one, not close to zero). Per bug #8274.
Fix by Andrew Gierth, some comment-smithing by me.
It's possible to drop a column from an input table of a JOIN clause in a
view, if that column is nowhere actually referenced in the view. But it
will still be there in the JOIN clause's joinaliasvars list. We used to
replace such entries with NULL Const nodes, which is handy for generation
of RowExpr expansion of a whole-row reference to the view. The trouble
with that is that it can't be distinguished from the situation after
subquery pull-up of a constant subquery output expression below the JOIN.
Instead, replace such joinaliasvars with null pointers (empty expression
trees), which can't be confused with pulled-up expressions. expandRTE()
still emits the old convention, though, for convenience of RowExpr
generation and to reduce the risk of breaking extension code.
In HEAD and 9.3, this patch also fixes a problem with some new code in
ruleutils.c that was failing to cope with implicitly-casted joinaliasvars
entries, as per recent report from Feike Steenbergen. That oversight was
because of an inadequate description of the data structure in parsenodes.h,
which I've now corrected. There were some pre-existing oversights of the
same ilk elsewhere, which I believe are now all fixed.
An ancient logic error in cfindloop() could cause the regex engine to fail
to find matches that begin later than the start of the string. This
function is only used when the regex pattern contains a back reference,
and so far as we can tell the error is only reachable if the pattern is
non-greedy (i.e. its first quantifier uses the ? modifier). Furthermore,
the actual match must begin after some potential match that satisfies the
DFA but then fails the back-reference's match test.
Reported and fixed by Jeevan Chalke, with cosmetic adjustments by me.
In tuplesort.c:inittapes(), we calculate tapeSpace by first figuring
out how many 'tapes' we can use (maxTapes) and then multiplying the
result by the tape buffer overhead for each. Unfortunately, when
we are on a system with an 8-byte long, we allow work_mem to be
larger than 2GB and that allows maxTapes to be large enough that the
32bit arithmetic can overflow when multiplied against the buffer
overhead.
When this overflow happens, we end up adding the overflow to the
amount of space available, causing the amount of memory allocated to
be larger than work_mem.
Note that to reach this point, you have to set work mem to at least
24GB and be sorting a set which is at least that size. Given that a
user who can set work_mem to 24GB could also set it even higher, if
they were looking to run the system out of memory, this isn't
considered a security issue.
This overflow risk was found by the Coverity scanner.
Back-patch to all supported branches, as this issue has existed
since before 8.4.
Make it easier for readers of the FP docs to find out about possibly
truncated values.
Per complaint from Tom Duffey in message
F0E0F874-C86F-48D1-AA2A-0C5365BF5118@trillitech.com
Author: Albe Laurenz
Reviewed by: Abhijit Menon-Sen
When there's a comment on an index that was created with UNIQUE or PRIMARY
KEY constraint syntax, we need to label the comment as depending on the
constraint not the index, since only the constraint object actually appears
in the dump. This incorrect dependency can lead to parallel pg_restore
trying to restore the comment before the index has been created, per bug
#8257 from Lloyd Albin.
This patch fixes pg_dump to produce the right dependency in dumps made
in the future. Usually we also try to hack pg_restore to work around
bogus dependencies, so that existing (wrong) dumps can still be restored in
parallel mode; but that doesn't seem practical here since there's no easy
way to relate the constraint dump entry to the comment after the fact.
Andres Freund
On Unix-ish platforms, EWOULDBLOCK may be the same as EAGAIN, which is
*not* a success return, at least not on Linux. We need to treat it as a
failure to avoid giving a misleading error message. Per the Single Unix
Spec, only EINPROGRESS and EINTR returns indicate that the connection
attempt is in progress.
On Windows, on the other hand, EWOULDBLOCK (WSAEWOULDBLOCK) is the expected
case. We must accept EINPROGRESS as well because Cygwin will return that,
and it doesn't seem worth distinguishing Cygwin from native Windows here.
It's not very clear whether EINTR can occur on Windows, but let's leave
that part of the logic alone in the absence of concrete trouble reports.
Also, remove the test for errno == 0, effectively reverting commit
da9501bddb, which AFAICS was just a thinko;
or at best it might have been a workaround for a platform-specific bug,
which we can hope is gone now thirteen years later. In any case, since
libpq makes no effort to reset errno to zero before calling connect(),
it seems unlikely that that test has ever reliably done anything useful.
Andres Freund and Tom Lane
Tom Lane