Richard Yen reported that pg_upgrade failed if the target cluster had
force_parallel_mode = on, because binary_upgrade_create_empty_extension()
is marked parallel restricted, allowing it to be executed in parallel
mode, which complains because it tries to acquire an XID.
In general, no function that might try to modify database data should
be considered parallel safe or restricted, since execution of it might
force XID acquisition. We found several other examples of this mistake.
Furthermore, functions that execute user-supplied SQL queries or query
fragments, or pull data from user-supplied cursors, had better be marked
both volatile and parallel unsafe, because we don't know what the supplied
query or cursor might try to do. There were several tsquery and XML
functions that had the wrong proparallel marking for this, and some of
them were even mislabeled as to volatility.
All these bugs are old, dating back to 9.6 for the proparallel mistakes
and much further for the provolatile mistakes. We can't force a
catversion bump in the back branches, but we can at least ensure that
installations initdb'd in future have the right values.
Thomas Munro and Tom Lane
Discussion: https://postgr.es/m/CAEepm=2sNDScSLTfyMYu32Q=ob98ZGW-vM_2oLxinzSABGQ6VA@mail.gmail.com
After processing the filemap to build the list of chunks that will be
fetched from the source to rewing the target server, it is possible that
a file which was previously processed is removed from the source. A
simple example of such an occurence is a WAL segment which gets recycled
on the target in-between. When the filemap is processed, files not
categorized as relation files are first truncated to prepare for its
full copy of which is going to be taken from the source, divided into a
set of junks. However, for a recycled WAL segment, this would result in
a segment which has a zero-byte size. With such an empty file,
post-rewind recovery thinks that records are saved but they are actually
not because of the truncation which happened when processing the
filemap, resulting in data loss.
In order to fix the problem, make sure that files which are found as
removed on the source when receiving chunks of them are as well deleted
on the target server for consistency.
Back-patch to 9.5 where pg_rewind was added.
Author: Tsunakawa Takayuki
Reviewed-by: Michael Paquier
Reported-by: Tsunakawa Takayuki
Discussion: https://postgr.es/m/0A3221C70F24FB45833433255569204D1F8DAAA2%40G01JPEXMBYT05
tuplesort_gettupleslot() passed back tuples allocated in the tuplesort's
own memory context, even when the caller was responsible to free them.
This created a double-free hazard, because some callers might destroy
the tuplesort object (via tuplesort_end) before trying to clean up the
last returned tuple. To avoid this, change the API to specify that the
tuple is allocated in the caller's memory context. v10 and HEAD already
did things that way, but in 9.5 and 9.6 this is a live bug that can
demonstrably cause crashes with some grouping-set usages.
In 9.5 and 9.6, this requires doing an extra tuple copy in some cases,
which is unfortunate. But the amount of refactoring needed to avoid it
seems excessive for a back-patched change, especially since the cases
where an extra copy happens are less performance-critical.
Likewise change tuplesort_getdatum() to return pass-by-reference Datums
in the caller's context not the tuplesort's context. There seem to be
no live bugs among its callers, but clearly the same sort of situation
could happen in future.
For other tuplesort fetch routines, continue to allocate the memory in
the tuplesort's context. This is a little inconsistent with what we now
do for tuplesort_gettupleslot() and tuplesort_getdatum(), but that's
preferable to adding new copy overhead in the back branches where it's
clearly unnecessary. These other fetch routines provide the weakest
possible guarantees about tuple memory lifespan from v10 on, anyway,
so this actually seems more consistent overall.
Adjust relevant comments to reflect these API redefinitions.
Arguably, we should change the pre-9.5 branches as well, but since
there are no known failure cases there, it seems not worth the risk.
Peter Geoghegan, per report from Bernd Helmle. Reviewed by Kyotaro
Horiguchi; thanks also to Andreas Seltenreich for extracting a
self-contained test case.
Discussion: https://postgr.es/m/1512661638.9720.34.camel@oopsware.de
The listed numbers disagreed with the ones being used in the symbols;
but instead of just fixing the numbers in the comment, use the symbolic
name instead, which seems clearer.
This has been wrong all along, so apply back to 9.5 where BRIN was
introduced.
Reported-by: Tomas Vondra
Discussion: https://postgr.es/m/5ff514f2-8b1e-6366-b11c-8e2ed442562d@2ndquadrant.com
Section 10.5 didn't say explicitly that multiple UNIONs are resolved
pairwise. Since the resolution algorithm is described as taking any
number of inputs, readers might well think that a query like
"select x union select y union select z" would be resolved by
considering x, y, and z in one resolution step. But that's not what
happens (and I think that behavior is per SQL spec). Add an example
clarifying this point.
Per bug #15129 from Philippe Beaudoin.
Discussion: https://postgr.es/m/152196085023.32649.9916472370480121694@wrigleys.postgresql.org
Extension scripts begin execution with pg_catalog at the front of the
search path, so type names reliably refer to pg_catalog. Remove these
superfluous qualifications. Earlier <programlisting> of this <sect1>
already omitted them. Back-patch to 9.3 (all supported versions).
For years, our makefiles have correctly observed that "there is no correct
way to write a rule that generates two files". However, what we did is to
provide empty rules that "generate" the secondary output files from the
primary one, and that's not right either. Depending on the details of
the creating process, the primary file might end up timestamped later than
one or more secondary files, causing subsequent make runs to consider the
secondary file(s) out of date. That's harmless in a plain build, since
make will just re-execute the empty rule and nothing happens. But it's
fatal in a VPATH build, since make will expect the secondary file to be
rebuilt in the build directory. This would manifest as "file not found"
failures during VPATH builds from tarballs, if we were ever unlucky enough
to ship a tarball with apparently out-of-date secondary files. (It's not
clear whether that has ever actually happened, but it definitely could.)
To ensure that secondary output files have timestamps >= their primary's,
change our makefile convention to be that we provide a "touch $@" action
not an empty rule. Also, make sure that this rule actually gets invoked
during a distprep run, else the hazard remains.
It's been like this a long time, so back-patch to all supported branches.
In HEAD, I skipped the changes in src/backend/catalog/Makefile, because
those rules are due to get replaced soon in the bootstrap data format
patch, and there seems no need to create a merge issue for that patch.
If for some reason we fail to land that patch in v11, we'll need to
back-fill the changes in that one makefile from v10.
Discussion: https://postgr.es/m/18556.1521668179@sss.pgh.pa.us
Count the number of tuples in the index honestly, instead of assuming
that it's the same as the number of tuples in the heap. (It might be
different if the index is partial.)
Back-patch to all supported versions.
Tomas Vondra
Discussion: https://postgr.es/m/3b3d8eac-c709-0d25-088e-b98339a1b28a@2ndquadrant.com
Count the number of tuples in the index honestly, instead of assuming
that it's the same as the number of tuples in the heap. (It might be
different if the index is partial.)
Fix counting of tuples in current index page, too. This error would
have led to failing to write out the final page of the index if it
contained exactly one tuple, so that the last tuple of the relation
would not get indexed.
Back-patch to 9.6 where contrib/bloom was added.
Tomas Vondra and Tom Lane
Discussion: https://postgr.es/m/3b3d8eac-c709-0d25-088e-b98339a1b28a@2ndquadrant.com
Code that prints out the contents of setconfig or proconfig arrays in
SQL format needs to handle GUC_LIST_QUOTE variables differently from
other ones, because for those variables, flatten_set_variable_args()
already applied a layer of quoting. The value can therefore safely
be printed as-is, and indeed must be, or flatten_set_variable_args()
will muck it up completely on reload. For all other GUC variables,
it's necessary and sufficient to quote the value as a SQL literal.
We'd recognized the need for this long ago, but mis-analyzed the
need slightly, thinking that all GUC_LIST_INPUT variables needed
the special treatment. That's actually wrong, since a valid value
of a LIST variable might include characters that need quoting,
although no existing variables accept such values.
More to the point, we hadn't made any particular effort to keep the
various places that deal with this up-to-date with the set of variables
that actually need special treatment, meaning that we'd do the wrong
thing with, for example, temp_tablespaces values. This affects dumping
of SET clauses attached to functions, as well as ALTER DATABASE/ROLE SET
commands.
In ruleutils.c we can fix it reasonably honestly by exporting a guc.c
function that allows discovering the flags for a given GUC variable.
But pg_dump doesn't have easy access to that, so continue the old method
of having a hard-wired list of affected variable names. At least we can
fix it to have just one list not two, and update the list to match
current reality.
A remaining problem with this is that it only works for built-in
GUC variables. pg_dump's list obvious knows nothing of third-party
extensions, and even the "ask guc.c" method isn't bulletproof since
the relevant extension might not be loaded. There's no obvious
solution to that, so for now, we'll just have to discourage extension
authors from inventing custom GUCs that need GUC_LIST_QUOTE.
This has been busted for a long time, so back-patch to all supported
branches.
Michael Paquier and Tom Lane, reviewed by Kyotaro Horiguchi and
Pavel Stehule
Discussion: https://postgr.es/m/20180111064900.GA51030@paquier.xyz
The original coding of the SP-GiST scan traversalValue feature (commit
ccd6eb49a) arranged for traversal values to be stored in the query's main
executor context. That's fine if there's only one index scan per query,
but if there are many, we have a memory leak as successive scans create
new traversal values. Fix it by creating a separate memory context for
traversal values, which we can reset during spgrescan(). Back-patch
to 9.6 where this code was introduced.
In principle, adding the traversalCxt field to SpGistScanOpaqueData
creates an ABI break in the back branches. But I (tgl) have little
sympathy for extensions including spgist_private.h, so I'm not very
worried about that. Alternatively we could stick the new field at the
end of the struct in back branches, but that has its own downsides.
Anton Dignös, reviewed by Alexander Kuzmenkov
Discussion: https://postgr.es/m/CALNdv1jb6y2Te-m8xHLxLX12RsBmZJ1f4hESX7J0HjgyOhA9eA@mail.gmail.com
refresh_by_match_merge() has some issues in the way it builds a SQL
query to construct the "diff" table:
1. It doesn't require the selected unique index(es) to be indimmediate.
2. It doesn't pay attention to the particular equality semantics enforced
by a given index, but just assumes that they must be those of the column
datatype's default btree opclass.
3. It doesn't check that the indexes are btrees.
4. It's insufficiently careful to ensure that the parser will pick the
intended operator when parsing the query. (This would have been a
security bug before CVE-2018-1058.)
5. It's not careful about indexes on system columns.
The way to fix#4 is to make use of the existing code in ri_triggers.c
for generating an arbitrary binary operator clause. I chose to move
that to ruleutils.c, since that seems a more reasonable place to be
exporting such functionality from than ri_triggers.c.
While #1, #3, and #5 are just latent given existing feature restrictions,
and #2 doesn't arise in the core system for lack of alternate opclasses
with different equality behaviors, #4 seems like an issue worth
back-patching. That's the bulk of the change anyway, so just back-patch
the whole thing to 9.4 where this code was introduced.
Discussion: https://postgr.es/m/13836.1521413227@sss.pgh.pa.us
Jeff Janes discovered that commit 7ca25b7de made one of the queries run by
REFRESH MATERIALIZED VIEW CONCURRENTLY perform badly. The root cause is
bad cardinality estimation for correlated quals, but a principled solution
to that problem is some way off, especially since the planner lacks any
statistics about whole-row variables. Moreover, in non-error cases this
query produces no rows, meaning it must be run to completion; but use of
LIMIT 1 encourages the planner to pick a fast-start, slow-completion plan,
exactly not what we want. Remove the LIMIT clause, and instead rely on
the count parameter we pass to SPI_execute() to prevent excess work if the
query does return some rows.
While we've heard no field reports of planner misbehavior with this query,
it could be that people are having performance issues that haven't reached
the level of pain needed to cause a bug report. In any case, that LIMIT
clause can't possibly do anything helpful with any existing version of the
planner, and it demonstrably can cause bad choices in some cases, so
back-patch to 9.4 where the code was introduced.
Thomas Munro
Discussion: https://postgr.es/m/CAMkU=1z-JoGymHneGHar1cru4F1XDfHqJDzxP_CtK5cL3DOfmg@mail.gmail.com
If a view lacks an INSTEAD OF trigger, DML on it can only work by rewriting
the command into a command on the underlying base table(s). Then we will
fire triggers attached to those table(s), not those for the view. This
seems appropriate from a consistency standpoint, but nowhere was the
behavior explicitly documented, so let's do that.
There was some discussion of throwing an error or warning if a statement
trigger is created on a view without creating a row INSTEAD OF trigger.
But a simple implementation of that would result in dump/restore ordering
hazards. Given that it's been like this all along, and we hadn't heard
a complaint till now, a documentation improvement seems sufficient.
Per bug #15106 from Pu Qun. Back-patch to all supported branches.
Discussion: https://postgr.es/m/152083391168.1215.16892140713507052796@wrigleys.postgresql.org
In e170b8c8, protection against modified search_path was added. However,
PostgreSQL versions prior to 10 does not accept SQL commands over a
replication connection, so the protection would generate a syntax error.
Since we cannot run SQL commands on it, we are also not vulnerable to
the issue that e170b8c8 fixes, so we can just skip this command for
older versions.
Author: Michael Paquier <michael@paquier.xyz>
The test to exit the loop if the integer control value would overflow
an int32 turns out not to work on some ICC versions, as it's dependent
on the assumption that the compiler will execute the code as written
rather than "optimize" it. ICC lacks any equivalent of gcc's -fwrapv
switch, so it was optimizing on the assumption of no integer overflow,
and that breaks this. Rewrite into a form that in fact does not
do any overflowing computations.
Per Tomas Vondra and buildfarm member fulmar. It's been like this
for a long time, although it was not till we added a regression test
case covering the behavior (in commit dd2243f2a) that the problem
became apparent. Back-patch to all supported versions.
Discussion: https://postgr.es/m/50562fdc-0876-9843-c883-15b8566c7511@2ndquadrant.com
"UPDATE/DELETE WHERE CURRENT OF cursor_name" failed, with an error message
like "cannot extract system attribute from virtual tuple", if the cursor
was using a index-only scan for the target table. Fix it by digging the
current TID out of the indexscan state.
It seems likely that the same failure could occur for CustomScan plans
and perhaps some FDW plan types, so that leaving this to be treated as an
internal error with an obscure message isn't as good an idea as it first
seemed. Hence, add a bit of heaptuple.c infrastructure to let us deliver
a more on-topic message. I chose to make the message match what you get
for the case where execCurrentOf can't identify the target scan node at
all, "cursor "foo" is not a simply updatable scan of table "bar"".
Perhaps it should be different, but we can always adjust that later.
In the future, it might be nice to provide hooks that would let custom
scan providers and/or FDWs deal with this in other ways; but that's
not a suitable topic for a back-patchable bug fix.
It's been like this all along, so back-patch to all supported branches.
Yugo Nagata and Tom Lane
Discussion: https://postgr.es/m/20180201013349.937dfc5f.nagata@sraoss.co.jp
ExecHashTableCreate allocated some memory that wasn't freed by
ExecHashTableDestroy, specifically the per-hash-key function information.
That's not a huge amount of data, but if one runs a query that repeats
a hash join enough times, it builds up. Fix by arranging for the data
in question to be kept in the hashtable's hashCxt instead of leaving it
"loose" in the query-lifespan executor context. (This ensures that we'll
also clean up anything that the hash functions allocate in fn_mcxt.)
Per report from Amit Khandekar. It's been like this forever, so back-patch
to all supported branches.
Discussion: https://postgr.es/m/CAJ3gD9cFofAWGvcxLOxDHC=B0hjtW8yGmUsF2hdGh97CM38=7g@mail.gmail.com
The existing logic for updating pg_class.reltuples trusted the sampling
results only for the pages ANALYZE actually visited, preferring to
believe the previous tuple density estimate for all the unvisited pages.
While there's some rationale for doing that for VACUUM (first that
VACUUM is likely to visit a very nonrandom subset of pages, and second
that we know for sure that the unvisited pages did not change), there's
no such rationale for ANALYZE: by assumption, it's looked at an unbiased
random sample of the table's pages. Furthermore, in a very large table
ANALYZE will have examined only a tiny fraction of the table's pages,
meaning it cannot slew the overall density estimate very far at all.
In a table that is physically growing, this causes reltuples to increase
nearly proportionally to the change in relpages, regardless of what is
actually happening in the table. This has been observed to cause reltuples
to become so much larger than reality that it effectively shuts off
autovacuum, whose threshold for doing anything is a fraction of reltuples.
(Getting to the point where that would happen seems to require some
additional, not well understood, conditions. But it's undeniable that if
reltuples is seriously off in a large table, ANALYZE alone will not fix it
in any reasonable number of iterations, especially not if the table is
continuing to grow.)
Hence, restrict the use of vac_estimate_reltuples() to VACUUM alone,
and in ANALYZE, just extrapolate from the sample pages on the assumption
that they provide an accurate model of the whole table. If, by very bad
luck, they don't, at least another ANALYZE will fix it; in the old logic
a single bad estimate could cause problems indefinitely.
In HEAD, let's remove vac_estimate_reltuples' is_analyze argument
altogether; it was never used for anything and now it's totally pointless.
But keep it in the back branches, in case any third-party code is calling
this function.
Per bug #15005. Back-patch to all supported branches.
David Gould, reviewed by Alexander Kuzmenkov, cosmetic changes by me
Discussion: https://postgr.es/m/20180117164916.3fdcf2e9@engels
In databases with many tables, re-fetching the statistics takes some time,
so that this behavior seriously decreases the available concurrency for
multiple autovac workers. There's discussion afoot about more complete
fixes, but a simple and back-patchable amelioration is to claim the table
and release the lock before rechecking stats. If we find out there's no
longer a reason to process the table, re-taking the lock to un-claim the
table is cheap enough.
(This patch is quite old, but got lost amongst a discussion of more
aggressive fixes. It's not clear when or if such a fix will be
accepted, but in any case it'd be unlikely to get back-patched.
Let's do this now so we have some improvement for the back branches.)
In passing, make the normal un-claim step take AutovacuumScheduleLock
not AutovacuumLock, since that is what is documented to protect the
wi_tableoid field. This wasn't an actual bug in view of the fact that
readers of that field hold both locks, but it creates some concurrency
penalty against operations that need only AutovacuumLock.
Back-patch to all supported versions.
Jeff Janes
Discussion: https://postgr.es/m/26118.1520865816@sss.pgh.pa.us
One of the things canonicalize_qual() does is to remove constant-NULL
subexpressions of top-level AND/OR clauses. It does that on the assumption
that what it's given is a top-level WHERE clause, so that NULL can be
treated like FALSE. Although this is documented down inside a subroutine
of canonicalize_qual(), it wasn't mentioned in the documentation of that
function itself, and some callers hadn't gotten that memo.
Notably, commit d007a9505 caused get_relation_constraints() to apply
canonicalize_qual() to CHECK constraints. That allowed constraint
exclusion to misoptimize situations in which a CHECK constraint had a
provably-NULL subclause, as seen in the regression test case added here,
in which a child table that should be scanned is not. (Although this
thinko is ancient, the test case doesn't fail before 9.2, for reasons
I've not bothered to track down in detail. There may be related cases
that do fail before that.)
More recently, commit f0e44751d added an independent bug by applying
canonicalize_qual() to index expressions, which is even sillier since
those might not even be boolean. If they are, though, I think this
could lead to making incorrect index entries for affected index
expressions in v10. I haven't attempted to prove that though.
To fix, add an "is_check" parameter to canonicalize_qual() to specify
whether it should assume WHERE or CHECK semantics, and make it perform
NULL-elimination accordingly. Adjust the callers to apply the right
semantics, or remove the call entirely in cases where it's not known
that the expression has one or the other semantics. I also removed
the call in some cases involving partition expressions, where it should
be a no-op because such expressions should be canonical already ...
and was a no-op, independently of whether it could in principle have
done something, because it was being handed the qual in implicit-AND
format which isn't what it expects. In HEAD, add an Assert to catch
that type of mistake in future.
This represents an API break for external callers of canonicalize_qual().
While that's intentional in HEAD to make such callers think about which
case applies to them, it seems like something we probably wouldn't be
thanked for in released branches. Hence, in released branches, the
extra parameter is added to a new function canonicalize_qual_ext(),
and canonicalize_qual() is a wrapper that retains its old behavior.
Patch by me with suggestions from Dean Rasheed. Back-patch to all
supported branches.
Discussion: https://postgr.es/m/24475.1520635069@sss.pgh.pa.us
The changes in the CREATE POLICY man page from commit
87c2a17fee triggered a stylesheet bug that
created some warning messages and incorrect output. This installs a
workaround.
Also improve the whitespace a bit so it looks better.
If a walsender exits leaving data in reorderbuffers, the next walsender
that tries to decode the same transaction would append its decoded data
in the same spill files without truncating it first, which effectively
duplicate the data. Avoid that by removing any leftover reorderbuffer
spill files when a walsender starts.
Backpatch to 9.4; this bug has been there from the very beginning of
logical decoding.
Author: Craig Ringer, revised by me
Reviewed by: Álvaro Herrera, Petr Jelínek, Masahiko Sawada
pg_rewind checks whether each file is a relation data file, from its path.
Previously this check logic had the bug which made pg_rewind fail to
recognize any relation data files in tablespaces. Which also caused
an assertion failure in pg_rewind.
Back-patch to 9.5 where pg_rewind was added.
Author: Takayuki Tsunakawa
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/0A3221C70F24FB45833433255569204D1F8D6C7A@G01JPEXMBYT05
If convert_to_scalar is passed a pair of datatypes it can't cope with,
its former behavior was just to elog(ERROR). While this is OK so far as
the core code is concerned, there's extension code that would like to use
scalarltsel/scalargtsel/etc as selectivity estimators for operators that
work on non-core datatypes, and this behavior is a show-stopper for that
use-case. If we simply allow convert_to_scalar to return FALSE instead of
outright failing, then the main logic of scalarltsel/scalargtsel will work
fine for any operator that behaves like a scalar inequality comparison.
The lack of conversion capability will mean that we can't estimate to
better than histogram-bin-width precision, since the code will effectively
assume that the comparison constant falls at the middle of its bin. But
that's still a lot better than nothing. (Someday we should provide a way
for extension code to supply a custom version of convert_to_scalar, but
today is not that day.)
While poking at this issue, we noted that the existing code for handling
type bytea in convert_to_scalar is several bricks shy of a load.
It assumes without checking that if the comparison value is type bytea,
the bounds values are too; in the worst case this could lead to a crash.
It also fails to detoast the input values, so that the comparison result is
complete garbage if any input is toasted out-of-line, compressed, or even
just short-header. I'm not sure how often such cases actually occur ---
the bounds values, at least, are probably safe since they are elements of
an array and hence can't be toasted. But that doesn't make this code OK.
Back-patch to all supported branches, partly because author requested that,
but mostly because of the bytea bugs. The change in API for the exposed
routine convert_network_to_scalar() is theoretically a back-patch hazard,
but it seems pretty unlikely that any third-party code is calling that
function directly.
Tomas Vondra, with some adjustments by me
Discussion: https://postgr.es/m/b68441b6-d18f-13ab-b43b-9a72188a4e02@2ndquadrant.com
In PostgreSQL 9.5, the documentation for pg_stat_replication was moved,
so some of the links pointed to an appropriate location.
Author: Maksim Milyutin <milyutinma@gmail.com>
Sloppy coding in this function could lead to leaking a VM buffer pin,
or to attempting to free the same pin twice. Repair. While at it,
reduce the code's tendency to free and reacquire the same page pin.
Back-patch to 9.6; before that, this routine did not concern itself
with VM pages.
Amit Kapila and Tom Lane
Discussion: https://postgr.es/m/CAA4eK1KJKwhc=isgTQHjM76CAdVswzNeAuZkh_cx-6QgGkSEgA@mail.gmail.com
Previously, it just returned the heap tuple count, which might be only an
estimate, and would be completely the wrong thing if the index is partial.
Since this function scans every index page anyway to find free pages,
it's practically free to count the surviving index tuples. Let's do that
and return an accurate count.
This is easily visible as a wrong reltuples value for a partial GiST
index following VACUUM, so back-patch to all supported branches.
Andrey Borodin, reviewed by Michail Nikolaev
Discussion: https://postgr.es/m/151956654251.6915.675951950408204404.pgcf@coridan.postgresql.org
These errors have been seen in the field in corrupted-data situations.
It seems worthwhile to report them with ERRCODE_DATA_CORRUPTED, rather
than the generic ERRCODE_INTERNAL_ERROR, for the benefit of log monitoring
and tools like amcheck. However, use errmsg_internal so that the text
strings still aren't translated; it seems unlikely to be worth
translators' time to do so.
Back-patch to 9.3, like the predecessor commit d70cf811f that introduced
these elog calls originally (replacing Asserts).
Peter Geoghegan
Discussion: https://postgr.es/m/CAH2-Wzmn4-Pg-UGFwyuyK-wiTih9j32pwg_7T9iwqXpAUZr=Mg@mail.gmail.com
Commit 4800f16a7a added some sanity checks to ensure we don't
accidentally corrupt data, but in one of them we failed to consider the
effects of a database upgraded from 9.2 or earlier, where a tuple
exclusively locked prior to the upgrade has a slightly different bit
pattern. Fix that by using the macro that we fixed in commit
74ebba84ae for similar situations.
Reported-by: Alexandre Garcia
Reviewed-by: Andres Freund
Discussion: https://postgr.es/m/CAPYLKR6yxV4=pfW0Gwij7aPNiiPx+3ib4USVYnbuQdUtmkMaEA@mail.gmail.com
Andres suspects that this bug may have wider ranging consequences, but I
couldn't find anything.
Since 9.5, it's possible that some but not all columns of an index
support returning the indexed value for index-only scans. If the
same indexed column appears in index columns that behave both ways,
check_index_only() supposed that it'd be OK to do an index-only scan
testing that column; but that fails if we have to recheck the indexed
condition on one of the columns that doesn't support this.
In principle we could make this work by remapping the recheck expressions
to pull the value from a column that does support returning the indexed
value. But such cases are so weird and rare that, at least for now,
it doesn't seem worth the trouble. Instead, just teach check_index_only
that a value is returnable only if all the index columns containing it
are returnable, rather than any of them.
Per report from David Pereiro Lagares. Back-patch to 9.5 where the
possibility of this situation appeared.
Kyotaro Horiguchi
Discussion: https://postgr.es/m/1516210494.1798.16.camel@nlpgo.com
Solaris 11.4 has built-in functions named b64_encode and b64_decode.
Rename ours to something else to avoid the conflict (fortunately,
ours are static so the impact is limited).
One could wish for less duplication of code in this area, but that
would be a larger patch and not very suitable for back-patching.
Since this is a portability fix, we want to put it into all supported
branches.
Report and initial patch by Rainer Orth, reviewed and adjusted a bit
by Michael Paquier
Discussion: https://postgr.es/m/ydd372wk28h.fsf@CeBiTec.Uni-Bielefeld.DE
specscanner.l had a fixed limit of 1024 bytes on the length of
individual SQL stanzas in an isolation test script. People are
starting to run into that, so fix it by making the buffer resizable.
Once we allow this in HEAD, it seems inevitable that somebody will
try to back-patch a test that exceeds the old limit, so back-patch
this change as a preventive measure.
Daniel Gustafsson
Discussion: https://postgr.es/m/8D628BE4-6606-4FF6-A3FF-8B2B0E9B43D0@yesql.se
Although configure-based builds correctly define HAVE_LONG_LONG_INT when
appropriate (in both pg_config.h and ecpg_config.h), builds using the MSVC
scripts failed to do so. This currently has no impact on the backend,
since it uses that symbol nowhere; but it does prevent ecpg from
supporting "long long int". Fix that.
Also, adjust Solution.pm so that in the constructed ecpg_config.h file,
the "#if (_MSC_VER > 1200)" covers only the LONG_LONG_INT-related
#defines, not the whole file. AFAICS this was a thinko on somebody's
part: ENABLE_THREAD_SAFETY should always be defined in Windows builds,
and in branches using USE_INTEGER_DATETIMES, the setting of that shouldn't
depend on the compiler version either. If I'm wrong, I imagine the
buildfarm will say so.
Per bug #15080 from Jonathan Allen; issue diagnosed by Michael Meskes
and Andrew Gierth. Back-patch to all supported branches.
Discussion: https://postgr.es/m/151935568942.1461.14623890240535309745@wrigleys.postgresql.org
I removed these functions altogether in HEAD, in commit db3af9feb, and
it emerges that that causes trouble for cross-branch upgrade testing.
We could put back stub functions but that seems pretty silly. Instead,
back-patch a minimal subset of db3af9feb, namely just removing the
CREATE FUNCTION commands.
Discussion: https://postgr.es/m/11927.1519756619@sss.pgh.pa.us
A before-update row trigger may choose to return the "new" or "old" tuple
unmodified. ExecBRUpdateTriggers failed to consider the second
possibility, and would proceed to free the "old" tuple even if it was the
one returned, leading to subsequent access to already-deallocated memory.
In debug builds this reliably leads to an "invalid memory alloc request
size" failure; in production builds it might accidentally work, but data
corruption is also possible.
This is a very old bug. There are probably a couple of reasons it hasn't
been noticed up to now. It would be more usual to return NULL if one
wanted to suppress the update action; returning "old" is significantly less
efficient since the update will occur anyway. Also, none of the standard
PLs would ever cause this because they all returned freshly-manufactured
tuples even if they were just copying "old". But commit 4b93f5799 changed
that for plpgsql, making it possible to see the bug with a plpgsql trigger.
Still, this is certainly legal behavior for a trigger function, so it's
ExecBRUpdateTriggers's fault not plpgsql's.
It seems worth creating a test case that exercises returning "old" directly
with a C-language trigger; testing this through plpgsql seems unreliable
because its behavior might change again.
Report and fix by Rushabh Lathia; regression test case by me.
Back-patch to all supported branches.
Discussion: https://postgr.es/m/CAGPqQf1P4pjiNPrMof=P_16E-DFjt457j+nH2ex3=nBTew7tXw@mail.gmail.com
The ability to create like-named objects in different schemas opens up
the potential for users to change the behavior of other users' queries,
maliciously or accidentally. When you connect to a PostgreSQL server,
you should remove from your search_path any schema for which a user
other than yourself or superusers holds the CREATE privilege. If you do
not, other users holding CREATE privilege can redefine the behavior of
your commands, causing them to perform arbitrary SQL statements under
your identity. "SET search_path = ..." and "SELECT
pg_catalog.set_config(...)" are not vulnerable to such hijacking, so one
can use either as the first command of a session. As special
exceptions, the following client applications behave as documented
regardless of search_path settings and schema privileges: clusterdb
createdb createlang createuser dropdb droplang dropuser ecpg (not
programs it generates) initdb oid2name pg_archivecleanup pg_basebackup
pg_config pg_controldata pg_ctl pg_dump pg_dumpall pg_isready
pg_receivewal pg_recvlogical pg_resetwal pg_restore pg_rewind pg_standby
pg_test_fsync pg_test_timing pg_upgrade pg_waldump reindexdb vacuumdb
vacuumlo. Not included are core client programs that run user-specified
SQL commands, namely psql and pgbench. PostgreSQL encourages non-core
client applications to do likewise.
Document this in the context of libpq connections, psql connections,
dblink connections, ECPG connections, extension packaging, and schema
usage patterns. The principal defense for applications is "SELECT
pg_catalog.set_config('search_path', '', false)", and the principal
defense for databases is "REVOKE CREATE ON SCHEMA public FROM PUBLIC".
Either one is sufficient to prevent attack. After a REVOKE, consider
auditing the public schema for objects named like pg_catalog objects.
Authors of SECURITY DEFINER functions use some of the same defenses, and
the CREATE FUNCTION reference page already covered them thoroughly.
This is a good opportunity to audit SECURITY DEFINER functions for
robust security practice.
Back-patch to 9.3 (all supported versions).
Reviewed by Michael Paquier and Jonathan S. Katz. Reported by Arseniy
Sharoglazov.
Security: CVE-2018-1058
