Relations dropped in a single transaction are tracked in a list of
unowned relations. With large number of dropped relations this resulted
in poor performance at the end of a transaction, when the relations are
removed from the singly linked list one by one.
Commit b4166911 attempted to address this issue (particularly when it
happens during recovery) by removing the relations in a reverse order,
resulting in O(1) lookups in the list of unowned relations. This did
not work reliably, though, and it was possible to trigger the O(N^2)
behavior in various ways.
Instead of trying to remove the relations in a specific order with
respect to the linked list, which seems rather fragile, switch to a
regular doubly linked. That allows us to remove relations cheaply no
matter where in the list they are.
As b4166911 was a bugfix, backpatched to all supported versions, do the
same thing here.
Reviewed-by: Alvaro Herrera
Discussion: https://www.postgresql.org/message-id/flat/80c27103-99e4-1d0c-642c-d9f3b94aaa0a%402ndquadrant.com
Backpatch-through: 9.4
The code would do "PQclear(res)" twice if lo_unlink failed, evidently
due to careless thinking about how far out a "break" would break.
Remove the extra PQclear and adjust the loop logic so that we'll fall
out of both levels of loop after an error, as was clearly the intent.
Spotted by Coverity. I have no idea why it took this long to notice,
since the bug has been there since commit 67ccbb080. Accordingly,
back-patch to all supported branches.
52ac6cd2d0 added new field to ginxlogDeletePage and was backpatched to 9.4.
That led to problems when patched postgres instance applies WAL records
generated by non-patched one. WAL records generated by non-patched instance
don't contain new field, which patched one is expecting to see.
Thankfully, we can distinguish patched and non-patched WAL records by their data
size. If we see that WAL record is generated by non-patched instance, we skip
processing of new field. This commit comes with some assertions. In
particular, if it appears that on some platform struct data size didn't change
then static assertion will trigger.
Reported-by: Simon Riggs
Discussion: https://postgr.es/m/CANP8%2Bj%2BK4whxf7ET7%2BgO%2BG-baC3-WxqqH%3DnV4X2CgfEPA3Yu3g%40mail.gmail.com
Author: Alexander Korotkov
Reviewed-by: Simon Riggs, Alvaro Herrera
Backpatch-through: 9.4
Previously we were using the SQL:2003 definition, which doesn't allow
this, but that creates a serious dump/restore gotcha: there is no
setting of xmloption that will allow all valid XML data. Hence,
switch to the 2006 definition.
Since libxml doesn't accept <!DOCTYPE> directives in the mode we
use for CONTENT parsing, the implementation is to detect <!DOCTYPE>
in the input and switch to DOCUMENT parsing mode. This should not
cost much, because <!DOCTYPE> should be close to the front of the
input if it's there at all. It's possible that this causes the
error messages for malformed input to be slightly different than
they were before, if said input includes <!DOCTYPE>; but that does
not seem like a big problem.
In passing, buy back a few cycles in parsing of large XML documents
by not doing strlen() of the whole input in parse_xml_decl().
Back-patch because dump/restore failures are not nice. This change
shouldn't break any cases that worked before, so it seems safe to
back-patch.
Chapman Flack (revised a bit by me)
Discussion: https://postgr.es/m/CAN-V+g-6JqUQEQZ55Q3toXEN6d5Ez5uvzL4VR+8KtvJKj31taw@mail.gmail.com
Commit 6f6a6d8b1 introduced a delay of up to 2 seconds if we're trying
to request a checkpoint but the checkpointer hasn't started yet (or,
much less likely, our kill() call fails). However buildfarm experience
shows that that's not quite enough for slow or heavily-loaded machines.
There's no good reason to assume that the checkpointer won't start
eventually, so we may as well make the timeout much longer, say 60 sec.
However, if the caller didn't say CHECKPOINT_WAIT, it seems like a bad
idea to be waiting at all, much less for as long as 60 sec. We can
remove the need for that, and make this whole thing more robust, by
adjusting the code so that the existence of a pending checkpoint
request is clear from the contents of shared memory, and making sure
that the checkpointer process will notice it at startup even if it did
not get a signal. In this way there's no need for a non-CHECKPOINT_WAIT
call to wait at all; if it can't send the signal, it can nonetheless
assume that the checkpointer will eventually service the request.
A potential downside of this change is that "kill -INT" on the checkpointer
process is no longer enough to trigger a checkpoint, should anyone be
relying on something so hacky. But there's no obvious reason to do it
like that rather than issuing a plain old CHECKPOINT command, so we'll
assume that nobody is. There doesn't seem to be a way to preserve this
undocumented quasi-feature without introducing race conditions.
Since a principal reason for messing with this is to prevent intermittent
buildfarm failures, back-patch to all supported branches.
Discussion: https://postgr.es/m/27830.1552752475@sss.pgh.pa.us
The assertions added by commits 34ea1ab7f et al found another problem:
set_dummy_rel_pathlist and mark_dummy_rel were failing to label
the dummy paths they create with the correct outer_relids, in case
the relation is necessarily parameterized due to having lateral
references in its tlist. It's likely that this has no user-visible
consequences in production builds, at the moment; but still an assertion
failure is a bad thing, so back-patch the fix.
Per bug #15694 from Roman Zharkov (via Alexander Lakhin)
and an independent report by Tushar Ahuja.
Discussion: https://postgr.es/m/15694-74f2ca97e7044f7f@postgresql.org
Discussion: https://postgr.es/m/7d72ab20-c725-3ce2-f99d-4e64dd8a0de6@enterprisedb.com
None of the code that uses GUC values is really prepared for them to
hold NaN, but parse_real() didn't have any defense against accepting
such a value. Treat it the same as a syntax error.
I haven't attempted to analyze the exact consequences of setting any
of the float GUCs to NaN, but since they're quite unlikely to be good,
this seems like a back-patchable bug fix.
Note: we don't need an explicit test for +-Infinity because those will
be rejected by existing range checks. I added a regression test for
that in HEAD, but not older branches because the spelling of the value
in the error message will be platform-dependent in branches where we
don't always use port/snprintf.c.
Discussion: https://postgr.es/m/1798.1552165479@sss.pgh.pa.us
The implementation of readdir() in src/port/ which gets used by MSVC has
been added in 399a36a, and since the beginning it considers all errors
on the first file lookup as ENOENT, setting errno accordingly and
letting the routine caller think that the directory is empty. While
this is normally enough for the case of the backend, this can confuse
callers of this routine on Windows as all errors would map to the same
behavior. So, for example, even permission errors would be thought as
having an empty directory, while there could be contents in it.
This commit changes the error handling so as readdir() gets a behavior
similar to native implementations: force errno=0 when seeing
ERROR_FILE_NOT_FOUND as error and consider other errors as plain
failures.
While looking at the patch, I noticed that MinGW does not enforce
errno=0 when looking at the first file, but it gets enforced on the next
file lookups. A comment related to that was incorrect in the code.
Reported-by: Yuri Kurenkov
Diagnosed-by: Yuri Kurenkov, Grigory Smolkin
Author: Konstantin Knizhnik
Reviewed-by: Andrew Dunstan, Michael Paquier
Discussion: https://postgr.es/m/2cad7829-8d66-e39c-b937-ac825db5203d@postgrespro.ru
Backpatch-through: 9.4
Previously, rewriteTargetListIU() generated a list of attribute
numbers from the targetlist, which were passed to rewriteValuesRTE(),
which expected them to contain the same number of entries as there are
columns in the VALUES RTE, and to be in the same order. That was fine
when the target relation was a table, but for an updatable view it
could be broken in at least three different ways ---
rewriteTargetListIU() could insert additional targetlist entries for
view columns with defaults, the view columns could be in a different
order from the columns of the underlying base relation, and targetlist
entries could be merged together when assigning to elements of an
array or composite type. As a result, when recursing to the base
relation, the list of attribute numbers generated from the rewritten
targetlist could no longer be relied upon to match the columns of the
VALUES RTE. We got away with that prior to 41531e42d3 because it used
to always be the case that rewriteValuesRTE() did nothing for the
underlying base relation, since all DEFAULTS had already been replaced
when it was initially invoked for the view, but that was incorrect
because it failed to apply defaults from the base relation.
Fix this by examining the targetlist entries more carefully and
picking out just those that are simple Vars referencing the VALUES
RTE. That's sufficient for the purposes of rewriteValuesRTE(), which
is only responsible for dealing with DEFAULT items in the VALUES
RTE. Any DEFAULT item in the VALUES RTE that doesn't have a matching
simple-Var-assignment in the targetlist is an error which we complain
about, but in theory that ought to be impossible.
Additionally, move this code into rewriteValuesRTE() to give a clearer
separation of concerns between the 2 functions. There is no need for
rewriteTargetListIU() to know about the details of the VALUES RTE.
While at it, fix the comment for rewriteValuesRTE() which claimed that
it doesn't support array element and field assignments --- that hasn't
been true since a3c7a993d5 (9.6 and later).
Back-patch to all supported versions, with minor differences for the
pre-9.6 branches, which don't support array element and field
assignments to the same column in multi-row VALUES lists.
Reviewed by Amit Langote.
Discussion: https://postgr.es/m/15623-5d67a46788ec8b7f@postgresql.org
Reflecting an updated parameter value requires a server restart, which
was not mentioned in the documentation and in postgresql.conf.sample.
Reported-by: Thomas Poty
Discussion: https://postgr.es/m/15659-0cd812f13027a2d8@postgresql.org
The Bison documentation clearly states that a semicolon is required
after every grammar rule, and our scripts that generate ecpg's
grammar from the backend's implicitly assumed this is true. But it
turns out that only ancient versions of Bison actually enforce that.
There have been a couple of rules without trailing semicolons in
gram.y for some time, and as a consequence, ecpg's grammar was faulty
and produced wrong output for the affected statements.
To fix, add the missing semis, and add some cross-checks to ecpg's
scripts so that they'll bleat if we mess this up again.
The cases that were broken were:
* "SET variable = DEFAULT" (but not "SET variable TO DEFAULT"),
as well as allied syntaxes such as ALTER SYSTEM SET ... DEFAULT.
These produced syntactically invalid output that the server
would reject.
* Multiple type names in DROP TYPE/DOMAIN commands. Only the
first type name would be listed in the emitted command.
Per report from Daisuke Higuchi. Back-patch to all supported versions.
Discussion: https://postgr.es/m/1803D792815FC24D871C00D17AE95905DB51CE@g01jpexmbkw24
Previously, we tolerated EBADF as a way for the operating system to
indicate that it doesn't support fsync() on a directory. Tolerate
EINVAL too, for older versions of Linux CIFS.
Bug #15636. Back-patch all the way.
Reported-by: John Klann
Discussion: https://postgr.es/m/15636-d380890dafd78fc6@postgresql.org
One unintended consequence of commit 9ccdd7f6 was that Windows WSL
users started getting a panic whenever we tried to initiate data
flushing with sync_file_range(), because WSL does not implement that
system call. Previously, they got a stream of periodic warnings,
which was also undesirable but at least ignorable.
Prevent the panic by handling ENOSYS specially and skipping the panic
promotion with data_sync_elevel(). Also suppress future attempts
after the first such failure so that the pre-existing problem of
noisy warnings is improved.
Back-patch to 9.6 (older branches were not affected in this way by
9ccdd7f6).
Author: Thomas Munro and James Sewell
Tested-by: James Sewell
Reported-by: Bruce Klein
Discussion: https://postgr.es/m/CA+mCpegfOUph2U4ZADtQT16dfbkjjYNJL1bSTWErsazaFjQW9A@mail.gmail.com
In the case where inheritance_planner() finds that every table has
been excluded by constraints, it thought it could get away with
making a plan consisting of just a dummy Result node. While certainly
there's no updating or deleting to be done, this had two user-visible
problems: the plan did not report the correct set of output columns
when a RETURNING clause was present, and if there were any
statement-level triggers that should be fired, it didn't fire them.
Hence, rather than only generating the dummy Result, we need to
stick a valid ModifyTable node on top, which requires a tad more
effort here.
It's been broken this way for as long as inheritance_planner() has
known about deleting excluded subplans at all (cf commit 635d42e9c),
so back-patch to all supported branches.
Amit Langote and Tom Lane, per a report from Petr Fedorov.
Discussion: https://postgr.es/m/5da6f0f0-1364-1876-6978-907678f89a3e@phystech.edu
Check ec_relids before bothering to iterate through the EC members.
On a perhaps extreme, but still real-world, query in which
match_eclasses_to_foreign_key_col() accounts for the bulk of the
planner's runtime, this saves nearly 40% of the runtime. It's a bit
of a stopgap fix, but it's simple enough to be back-patched to 9.6
where this code came in; so let's do that.
David Rowley
Discussion: https://postgr.es/m/6970.1545327857@sss.pgh.pa.us
pg_identify_object_as_address crashes when passed certain tuples from
inconsistent system catalogs. Make it more defensive.
Author: Álvaro Herrera
Reviewed-by: Michaël Paquier
Discussion: https://postgr.es/m/20190218202743.GA12392@alvherre.pgsql
INSERT ... VALUES for a single VALUES row is implemented differently
from a multi-row VALUES list, which causes inconsistent behaviour in
the way that DEFAULT items are handled. In particular, when inserting
into an auto-updatable view on top of a table with a column default, a
DEFAULT item in a single VALUES row gets correctly replaced with the
table column's default, but for a multi-row VALUES list it is replaced
with NULL.
Fix this by allowing rewriteValuesRTE() to leave DEFAULT items in the
VALUES list untouched if the target relation is an auto-updatable view
and has no column default, deferring DEFAULT-expansion until the query
against the base relation is rewritten. For all other types of target
relation, including tables and trigger- and rule-updatable views, we
must continue to replace DEFAULT items with NULL in the absence of a
column default.
This is somewhat complicated by the fact that if an auto-updatable
view has DO ALSO rules attached, the VALUES lists for the product
queries need to be handled differently from the original query, since
the product queries need to act like rule-updatable views whereas the
original query has auto-updatable view semantics.
Back-patch to all supported versions.
Reported by Roger Curley (bug #15623). Patch by Amit Langote and me.
Discussion: https://postgr.es/m/15623-5d67a46788ec8b7f@postgresql.org
When building an initial slot snapshot, snapshots are marked with
historic MVCC snapshots as type with the marker field being set in
SnapBuildBuildSnapshot() but not overriden in SnapBuildExportSnapshot().
Existing callers of SnapBuildBuildSnapshot() do not care about the type
of snapshot used, but extensions calling it actually may, as reported.
Author: Antonin Houska
Reviewed-by: Álvaro Herrera, Michael Paquier
Discussion: https://postgr.es/m/23215.1527665193@localhost
Backpatch-through: 9.4
The dblink documentation claims that an empty string is returned if there
has been no error, however OK is actually returned in that case. Also,
clarify that an async error may not be seen unless dblink_is_busy() or
dblink_get_result() have been called first.
Backpatch to all supported branches.
Reported-by: realyota
Backpatch-through: 9.4
Discussion: https://postgr.es/m/153371978486.1298.2091761143788088262@wrigleys.postgresql.org
We should logically have allowed this case when we allowed zero-column
tables, but it was overlooked.
Although this might be thought a feature addition, it's really a bug
fix, because it was possible to create a zero-column view via
the convert-table-to-view code path, and then you'd have a situation
where dump/reload would fail. Hence, back-patch to all supported
branches.
Arrange the added test cases to provide coverage of the related
pg_dump code paths (since these views will be dumped and reloaded
during the pg_upgrade regression test). I also made them test
the case where pg_dump has to postpone the view rule into post-data,
which disturbingly had no regression coverage before.
Report and patch by Ashutosh Sharma (test case by me)
Discussion: https://postgr.es/m/CAE9k0PkmHdeSaeZt2ujnb_cKucmK3sDDceDzw7+d5UZoNJPYOg@mail.gmail.com
The grammar IF NOT EXISTS for CTAS is supported since 9.5 and documented
as such, however the case of using EXECUTE as query has never been
covered as EXECUTE CTAS statements and normal CTAS statements are parsed
separately.
Author: Andreas Karlsson
Discussion: https://postgr.es/m/2ddcc188-e37c-a0be-32bf-a56b07c3559e@proxel.se
Backpatch-through: 9.5
DSM handle values can be reused as soon as the underlying shared memory
object has been destroyed. That means that for a brief moment we
might have two DSM slots with the same handle. While trying to attach,
if we encounter a slot with refcnt == 1, meaning that it is currently
being destroyed, we should continue our search in case the same handle
exists in another slot.
The race manifested as a rare "dsa_area could not attach to segment"
error, and was more likely in 10 and 11 due to the lack of distinct
seed for random() in parallel workers. It was made very unlikely in
in master by commit 197e4af9, and older releases don't usually create
new DSM segments in background workers so it was also unlikely there.
This fixes the root cause of bug report #15585, in which the error
could also sometimes result in a self-deadlock in the error path.
It's not yet clear if further changes are needed to avoid that failure
mode.
Back-patch to 9.4, where dsm.c arrived.
Author: Thomas Munro
Reported-by: Justin Pryzby, Sergei Kornilov
Discussion: https://postgr.es/m/20190207014719.GJ29720@telsasoft.com
Discussion: https://postgr.es/m/15585-324ff6a93a18da46@postgresql.org
Ever since its birth, ReorderBufferBuildTupleCidHash() has contained an
assertion that a catalog tuple cannot change Cmax after acquiring one. But
that's wrong: if a subtransaction executes DDL that affects that catalog
tuple, and later aborts and another DDL affects the same tuple, it will
change Cmax. Relax the assertion to merely verify that the Cmax remains
valid and monotonically increasing, instead.
Add a test that tickles the relevant code.
Diagnosed by, and initial patch submitted by: Arseny Sher
Co-authored-by: Arseny Sher
Discussion: https://postgr.es/m/874l9p8hyw.fsf@ars-thinkpad
It's pretty unhelpful to report the wrong file name in a complaint
about syscall failure, but SnapBuildSerialize managed to do that twice
in a span of 50 lines. Also fix half a dozen missing or poorly-chosen
errcode assignments; that's mostly cosmetic, but still wrong.
Noted while studying recent failures on buildfarm member nightjar.
I'm not sure whether those reports are actually giving the wrong
filename, because there are two places here with identically
spelled error messages. The other one is specifically coded not
to report ENOENT, but if it's this one, how could we be getting
ENOENT from open() with O_CREAT? Need to sit back and await results.
However, these ereports are clearly broken from birth, so back-patch.
Renaming varchar_transform to varchar_support had a side effect
I hadn't foreseen: the core regression tests leave around a
transform object that relies on that function, so the name
change breaks cross-version upgrade tests, because the name
used in the older branches doesn't match.
Since the dependency on varchar_transform was chosen with the
aid of a dartboard anyway (it would surely not work as a
language transform support function), fix by just choosing
a different random builtin function with the right signature.
Also add some comments explaining why this isn't horribly unsafe.
I chose to make the same substitution in a couple of other
copied-and-pasted test cases, for consistency, though those
aren't directly contributing to the testing problem.
Per buildfarm. Back-patch, else it doesn't fix the problem.
warn_or_exit_horribly() was blithely passing a potentially-NULL
string pointer to a %s format specifier. That works (at least
to the extent of not crashing) on some platforms, but not all,
and since we switched to our own snprintf.c it doesn't work
for us anywhere.
Of the three string fields being handled this way here, I think
that only "owner" is supposed to be nullable ... but considering
that this is error-reporting code, it has very little business
assuming anything, so put in defenses for all three.
Per a crash observed on buildfarm member crake and then
reproduced here. Because of the portability aspect,
back-patch to all supported versions.
The previous ordering of these steps satisfied the nominal requirement
that set_rel_pathlist_hook could editorialize on the whole set of Paths
constructed for a base relation. In practice, though, trying to change
the set of partial paths was impossible. Adding one didn't work because
(a) it was too late to be included in Gather paths made by the core code,
and (b) calling add_partial_path after generate_gather_paths is unsafe,
because it might try to delete a path it thinks is dominated, but that
is already embedded in some Gather path(s). Nor could the hook safely
remove partial paths, for the same reason that they might already be
embedded in Gathers.
Better to call extensions first, let them add partial paths as desired,
and then gather. In v11 and up, we already doubled down on that ordering
by postponing gathering even further for single-relation queries; so even
if the hook wished to editorialize on Gather path construction, it could
not.
Report and patch by KaiGai Kohei. Back-patch to 9.6 where Gather paths
were added.
Discussion: https://postgr.es/m/CAOP8fzahwpKJRTVVTqo2AE=mDTz_efVzV6Get_0=U3SO+-ha1A@mail.gmail.com
While this isn't really supposed to happen, it can occur in OOM
situations and perhaps others. Instead of crashing, substitute
"(no message provided)".
I didn't worry about localizing this text, since we aren't
localizing anything else here; besides, if we're on the edge of
OOM, it's unlikely gettext() would work.
Report and fix by Sergio Conde Gómez in bug #15624.
Discussion: https://postgr.es/m/15624-4dea54091a2864e6@postgresql.org
As reported in bug #15613 from Srinivasan S A, file_fdw and postgres_fdw
neglected to mark plain baserel foreign paths as parameterized when the
relation has lateral_relids. Other FDWs have surely copied this mistake,
so rather than just patching those two modules, install a band-aid fix
in create_foreignscan_path to rectify the mistake centrally.
Although the band-aid is enough to fix the visible symptom, correct
the calls in file_fdw and postgres_fdw anyway, so that they are valid
examples for external FDWs.
Also, since the band-aid isn't enough to make this work for parameterized
foreign joins, throw an elog(ERROR) if such a case is passed to
create_foreignscan_path. This shouldn't pose much of a problem for
existing external FDWs, since it's likely they aren't trying to make such
paths anyway (though some of them may need a defense against joins with
lateral_relids, similar to the one this patch installs into postgres_fdw).
Add some assertions in relnode.c to catch future occurrences of the same
error --- in particular, as backstop against core-code mistakes like the
one fixed by commit bdd9a99aa.
Discussion: https://postgr.es/m/15613-092be1be9576c728@postgresql.org
The modules RewindTest.pm and ServerSetup.pm are really only useful for
TAP tests, so they really belong in the TAP test directories. In
addition, ServerSetup.pm is renamed to SSLServer.pm.
The test scripts have their own directories added to the search path so
that the relocated modules will be found, regardless of where the tests
are run from, even on modern perl where "." is no longer in the
searchpath.
Discussion: https://postgr.es/m/e4b0f366-269c-73c3-9c90-d9cb0f4db1f9@2ndQuadrant.com
Backpatch as appropriate to 9.5
create_lateral_join_info() computes a bunch of information about lateral
references between base relations, and then attempts to propagate those
markings to appendrel children of the original base relations. But the
original coding neglected the possibility of indirect descendants
(grandchildren etc). During v11 development we noticed that this was
wrong for partitioned-table cases, but failed to realize that it was just
as wrong for any appendrel. While the case can't arise for appendrels
derived from traditional table inheritance (because we make a flat
appendrel for that), nested appendrels can arise from nested UNION ALL
subqueries. Failure to mark the lower-level relations as having lateral
references leads to confusion in add_paths_to_append_rel about whether
unparameterized paths can be built. It's not very clear whether that
leads to any user-visible misbehavior; the lack of field reports suggests
that it may cause nothing worse than minor cost misestimation. Still,
it's a bug, and it leads to failures of Asserts that I intend to add
later.
To fix, we need to propagate information from all appendrel parents,
not just those that are RELOPT_BASERELs. We can still do it in one
pass, if we rely on the append_rel_list to be ordered with ancestor
relationships before descendant ones; add assertions checking that.
While fixing this, we can make a small performance improvement by
traversing the append_rel_list just once instead of separately for
each appendrel parent relation.
Noted while investigating bug #15613, though this patch does not fix
that (which is why I'm not committing the related Asserts yet).
Discussion: https://postgr.es/m/3951.1549403812@sss.pgh.pa.us
Commit f83419b739 failed to notice that mkvcbuild.pl and build.pl use
different searchpath and do-file logic, breaking the latter, so it is
adjusted to use the same logic as mkvcbuild.pl.
Contrary to the comment on 772d4b76, only paths starting with "./" or
"../" are considered relative to the current working directory by perl's
"do" function. So this patch converts all the relevant cases to use "./"
paths. This only affects MSVC.
Backpatch to all live branches.
Use "do" instead of "require" for included files, as it doesn't look for
them in the search path but relative to the current working directory.
These changes have already been made to REL_10_STABLE and later, to
satisfy the demands of perlcritic, but need backporting now to earlier
branches.
