Given a three-or-more-way equivalence class, such as X.Y = Y.Y = Z.Z,
it was possible for the planner to omit one of the quals needed to
enforce that all members of the equivalence class are actually equal.
This only happened in the case of a parameterized join node for two
of the relations, that is a plan tree like
Nested Loop
-> Scan X
-> Nested Loop
-> Scan Y
-> Scan Z
Filter: Z.Z = X.X
The eclass machinery normally expects to apply X.X = Y.Y when those
two relations are joined, but in this shape of plan tree they aren't
joined until the top node --- and, if the lower nested loop is marked
as parameterized by X, the top node will assume that the relevant eclass
condition(s) got pushed down into the lower node. On the other hand,
the scan of Z assumes that it's only responsible for constraining Z.Z
to match any one of the other eclass members. So one or another of
the required quals sometimes fell between the cracks, depending on
whether consideration of the eclass in get_joinrel_parampathinfo()
for the lower nested loop chanced to generate X.X = Y.Y or X.X = Z.Z
as the appropriate constraint there. If it generated the latter,
it'd erroneously suppose that the Z scan would take care of matters.
To fix, force X.X = Y.Y to be generated and applied at that join node
when this case occurs.
This is *extremely* hard to hit in practice, because various planner
behaviors conspire to mask the problem; starting with the fact that the
planner doesn't really like to generate a parameterized plan of the
above shape. (It might have been impossible to hit it before we
tweaked things to allow this plan shape for star-schema cases.) Many
thanks to Alexander Kirkouski for submitting a reproducible test case.
The bug can be demonstrated in all branches back to 9.2 where parameterized
paths were introduced, so back-patch that far.
Without a few entries beyond old_snapshot_threshold, the lookup
would often fail, resulting in the more aggressive pruning or
vacuum being skipped often enough to matter. This was very clearly
shown by a python test script posted by Ants Aasma, and was likely
a factor in an earlier but somewhat less clear-cut test case posted
by Jeff Janes.
This patch makes no change to the logic, per se -- it just makes
the array of mapping entries big enough to make lookup misses based
on timing much less likely. An occasional miss is still possible
if a thread stalls for more than 10 minutes, but that does not
create any problem with correctness of behavior. Besides, if
things are so busy that a thread is stalling for more than 10
minutes, it is probably OK to skip the more aggressive cleanup at
that particular point in time.
Adjust the way we detect the locale. As a result the minumum Windows
version supported by VS2015 and later is Windows Vista. Add some tweaks
to remove new compiler warnings. Remove documentation references to the
now obsolete msysGit.
Michael Paquier, somewhat edited by me, reviewed by Christian Ullrich.
Backpatch to 9.5
Since 5a991ef8 we're explicitly asking for feedback from the receiving
side when shutting down walsender, if there's not yet replicated
data.
Unfortunately we didn't remember (i.e. set waiting_for_ping_response to
true) having asked for feedback, leading to scenarios in which replies
were requested at a high frequency.
I can't reproduce this problem on my laptop, I think that's because the
problem requires a significant TCP window to manifest due to the
!pq_is_send_pending() condition. But since this clearly is a bug, let's
fix it. There's quite possibly more wrong than just this though.
While fiddling with WalSndDone(), I rewrote a hard to understand comment
about looking at the flush vs. the write position.
Reported-By: Nick Cleaton, Magnus Hagander
Author: Nick Cleaton
Discussion: CAFgz3kus=rC_avEgBV=+hRK5HYJ8vXskJRh8yEAbahJGTzF2VQ@mail.gmail.comCABUevExsjROqDcD0A2rnJ6HK6FuKGyewJr3PL12pw85BHFGS2Q@mail.gmail.com
Backpatch: 9.4, were 5a991ef8 introduced the use of feedback messages
during shutdown.
Commit 23a41573c attempted to fix the DatumGetBool macro to ignore bits
in a Datum that are to the left of the actual bool value. But it did that
by casting the Datum to bool; and on compilers that use C99 semantics for
bool, that ends up being a whole-word test, not a 1-byte test. This seems
to be the true explanation for contrib/seg failing in VS2015. To fix, use
GET_1_BYTE() explicitly. I think in the previous patch, I'd had some idea
of not having to commit to bool being exactly 1 byte wide, but regardless
of what the compiler's bool is, boolean columns and Datums are certainly
1 byte wide.
The previous fix was (eventually) back-patched into all active versions,
so do likewise with this one.
This reverts commit c8e81afc60.
That turns out to have been based on a faulty diagnosis of why the
VS2015 build was misbehaving. Instead, we need to fix DatumGetBool().
Previously, ginInsertCleanup could exit early if it detects that someone else
is cleaning up the pending list, without waiting for that someone else to
finish the job. But in this case vacuum could miss tuples to be deleted.
Cleanup process now locks metapage with a help of heavyweight
LockPage(ExclusiveLock), and it guarantees that there is no another cleanup
process at the same time. Lock is taken differently depending on caller of
cleanup process: any vacuums and gin_clean_pending_list() will be blocked
until lock becomes available, ordinary insert uses conditional lock to
prevent indefinite waiting on lock.
Insert into pending list doesn't use this lock, so insertion isn't blocked.
Also, patch adds stopping of cleanup process when at-start-cleanup-tail is
reached in order to prevent infinite cleanup in case of massive insertion. But
it will stop only for automatic maintenance tasks like autovacuum.
Patch introduces choice of limit of memory to use: autovacuum_work_mem,
maintenance_work_mem or work_mem depending on call path.
Patch for previous releases should be reworked due to changes between 9.6 and
previous ones in this area.
Discover and diagnostics by Jeff Janes and Tomas Vondra
Patch by me with some ideas of Jeff Janes
The previous coding here was formally undefined, though it seems to
accidentally work on most platforms in the buildfarm. Caught by some
OpenBSD platforms in which libc contains an assertion check for
overlapping areas passed to memcpy().
Thomas Munro
Commit 989be0810d added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
In addition to adding new typedefs, I also re-sorted the file so that
various entries add piecemeal, mostly or entirely by me, were alphabetized
the same way as other entries in the file.
In nodeFuncs.c, pgindent wants to introduce spurious indentation into
the definitions of planstate_tree_walker and planstate_walk_subplans.
Fix that by spreading the definition out across several lines, similar
to what is already done for other walker functions in that file.
In execParallel.c, in the definition of SharedExecutorInstrumentation,
pgindent wants to insert more whitespace between the type name and the
member name. That causes it to mangle comments later on the line. Fix
by moving the comments out of line. Now that we have a bit more room,
add some more details that may be useful to the next person reading
this code.
The way that PartialAggregate and FinalizeAggregate plan nodes were
displaying output columns before was bogus. Now, FinalizeAggregate
produces the same outputs as an Aggregate would have produced, while
PartialAggregate produces each of those outputs prefixed by the word
PARTIAL.
Discussion: 12585.1460737650@sss.pgh.pa.us
Patch by me, reviewed by David Rowley.
Before this commit _mdfd_getseg(), in contrast to mdnblocks(), did not
verify whether all segments leading up to the to-be-opened one, were
RELSEG_SIZE sized. That is e.g. not the case after truncating a
relation, because later segments just get truncated to zero length, not
removed.
Once a "non-existent" segment has been opened in a session, mdnblocks()
will return wrong results, causing errors like "could not read block %u
in file" when accessing blocks. Closing the session, or the later
arrival of relevant invalidation messages, would "fix" the problem.
That, so far, was mostly harmless, because most segment accesses are
only done after an mdnblocks() call. But since 428b1d6b29 we try to
open segments that might have been deleted, to trigger kernel writeback
from a backend's queue of recent writes.
To fix check segment sizes in _mdfd_getseg() when opening previously
unopened segments. In practice this shouldn't imply a lot of additional
lseek() calls, because mdnblocks() will most of the time already have
opened all relevant segments.
This commit also fixes a second problem, namely that _mdfd_getseg(
EXTENSION_RETURN_NULL) extends files during recovery, which is not
desirable for the mdwriteback() case. Add EXTENSION_REALLY_RETURN_NULL,
which does not behave that way, and use it.
Reported-By: Thom Brown
Author: Andres Freund, Abhijit Menon-Sen
Reviewd-By: Robert Haas, Fabien Coehlo
Discussion: CAA-aLv6Dp_ZsV-44QA-2zgkqWKQq=GedBX2dRSrWpxqovXK=Pg@mail.gmail.com
Fixes: 428b1d6b29
So far, when a transaction with pending invalidations, but without an
assigned xid, committed, we simply ignored those invalidation
messages. That's problematic, because those are actually sent for a
reason.
Known symptoms of this include that existing sessions on a hot-standby
replica sometimes fail to notice new concurrently built indexes and
visibility map updates.
The solution is to WAL log such invalidations in transactions without an
xid. We considered to alternatively force-assign an xid, but that'd be
problematic for vacuum, which might be run in systems with few xids.
Important: This adds a new WAL record, but as the patch has to be
back-patched, we can't bump the WAL page magic. This means that standbys
have to be updated before primaries; otherwise
"PANIC: standby_redo: unknown op code 32" errors can be encountered.
XXX:
Reported-By: Васильев Дмитрий, Masahiko Sawada
Discussion:
CAB-SwXY6oH=9twBkXJtgR4UC1NqT-vpYAtxCseME62ADwyK5OA@mail.gmail.comCAD21AoDpZ6Xjg=gFrGPnSn4oTRRcwK1EBrWCq9OqOHuAcMMC=w@mail.gmail.com
pg_atomic_compare_exchange_*_impl() were providing only the semantics of
an acquire barrier. Buildfarm members hornet and mandrill revealed this
deficit beginning with commit 008608b9d5.
While we have no report of symptoms in 9.5, we can't rule out the
possibility of certain compilers, hardware, or extension code relying on
these functions' specified barrier semantics. Back-patch to 9.5, where
commit b64d92f1a5 introduced atomics.
Reviewed by Andres Freund.
In commit c0b050192, Andres introduced the idea of including one-line
commit references in our major release notes. Teach git_changelog to
emit a (lightly adapted) version of that format, so that we don't
have to laboriously add it to the notes after the fact. The default
output isn't changed, since I anticipate still using that for minor
release notes.
Previously, database clusters created by a TAP test were shut down by
DESTROY methods attached to the PostgresNode objects representing them.
The trouble with that is that if the objects survive into the final global
destruction phase (which they do), Perl executes the DESTROY methods in an
unspecified order. Thus, the order of shutdown of multiple clusters was
indeterminate, which might lead to not-very-reproducible errors getting
logged (eg from a slave whose master might or might not get killed first).
Worse, the File::Temp objects representing the temporary PGDATA directories
might get destroyed before the PostgresNode objects, resulting in attempts
to delete PGDATA directories that still have live servers in them. On
Windows, this would lead to directory deletion failures; on Unix, it
usually had no effects worse than erratic "could not open temporary
statistics file "pg_stat/global.tmp": No such file or directory" log
messages.
While none of this would affect the reported result of the TAP test, which
is already determined, it could be very confusing when one is trying to
understand from the logs what went wrong with a failed test.
To fix, do the postmaster shutdowns in an END block rather than at object
destruction time. The END block will execute at a well-defined (and
reasonable) time during script termination, and it will stop the
postmasters in order of PostgresNode object creation. (Perhaps we should
change that to be reverse order of creation, but the main point here is
that we now have control which we did not before.) Use "pg_ctl stop", not
an asynchronous kill(SIGQUIT), so that we wait for the postmasters to shut
down before proceeding with directory deletion.
Deletion of temporary directories still happens in an unspecified order
during global destruction, but I can see no reason to care about that
once the postmasters are stopped.
The true explanation for Peter Eisentraut's report of inexact asind results
seems to be that (a) he's compiling into x87 instruction set, which uses
wider-than-double float registers, plus (b) the library function asin() on
his platform returns a result that is wider than double and is not rounded
to double width. To fix, we have to force the function's result to be
rounded comparably to what happened to the scaling constant asin_0_5.
Experimentation suggests that storing it into a volatile local variable is
the least ugly way of making that happen. Although only asin() is known to
exhibit an observable inexact result, we'd better do this in all the places
where we're hoping to get an exact result by scaling.
Change max_parallel_degree default from 0 to 2. It is possible that
this is not a good idea, or that we should go with 1 worker rather
than 2, but we won't find out without trying it. Along the way,
reword the documentation for max_parallel_degree a little bit to
hopefully make it more clear.
Discussion: 20160420174631.3qjjhpwsvvx5bau5@alap3.anarazel.de
Commit 65abaab547 tried to prevent the scaling constants used in
the degree-based trig functions from being precomputed at compile time,
because some compilers do that with functions that don't yield results
identical-to-the-last-bit to what you get at runtime. A report from
Peter Eisentraut suggests that some recent compilers are smart enough
to see through that trick, though. Instead, let's put the inputs to
these calculations into non-const global variables, which should be a
more reliable way of convincing the compiler that it can't assume that
they are compile-time constants. (If we really get desperate, we could
mark these variables "volatile", but I do not believe we should have to.)
Commit fab84c7787 tried to get away without doing an actual bind(),
but buildfarm results show that that doesn't get the job done. So we must
really bind to the target port --- and at least on my Linux box, we need a
listen() as well, or conflicts won't be detected. We rely on SO_REUSEADDR
to prevent problems from starting a postmaster on the socket immediately
after we've bound to it in the test code. (There may be platforms where
that doesn't work too well. But fortunately, we only really care whether
this works on Windows, and there the default behavior should be OK.)
Buildfarm members bowerbird and jacana have shown intermittent "could not
bind IPv4 socket" failures in the BinInstallCheck stage since mid-December,
shortly after commits 1caef31d9e and 9821492ee4 changed the
logic for selecting which port to use in temporary installations. One
plausible explanation is that we are randomly selecting ports that are
already in use for some non-Postgres purpose. Although the code tried
to defend against already-in-use ports, it used pg_isready to probe
the port which is quite unhelpful: if some non-Postgres server responds
at the given address, pg_isready will generally say "no response",
leading to exactly the wrong conclusion about whether the port is free.
Instead, let's use a simple TCP connect() call to see if anything answers
without making assumptions about what it is. Note that this means there's
no direct check for a conflicting Unix socket, but that should be okay
because there should be no other Unix sockets in use in the temporary
socket directory created for a test run.
This is only a partial solution for the TCP case, since if the port number
is in use for an outgoing connection rather than a listening socket, we'll
fail to detect that. We could try to bind() to the proposed port as a
means of detecting that case, but that would introduce its own failure
modes, since the system might consider the address to remain reserved for
some period of time after we drop the bound socket. Close study of the
errors returned by bowerbird and jacana suggests that what we're seeing
there may be conflicts with listening not outgoing sockets, so let's try
this and see if it improves matters. It's certainly better than what's
there now, in any case.
Michael Paquier, adjusted by me to work on non-Windows as well as Windows
Several issues:
1) checkpoint_flush_after doc and code disagreed about the default
2) new GUCs were missing from postgresql.conf.sample
3) Outdated source-code comment about bgwriter_flush_after's default
4) Sub-optimal categories assigned to new GUCs
5) Docs suggested backend_flush_after is PGC_SIGHUP, but it's PGC_USERSET.
6) Spell out int as integer in the docs, as done elsewhere
Reported-By: Magnus Hagander, Fujii Masao
Discussion: CAHGQGwETyTG5VYQQ5C_srwxWX7RXvFcD3dKROhvAWWhoSBdmZw@mail.gmail.com
NetBSD has seen fit to invent a libc function named strtoi(), which
conflicts with the long-established static functions of the same name in
datetime.c and ecpg's interval.c. While muttering darkly about intrusions
on application namespace, we'll rename our functions to avoid the conflict.
Back-patch to all supported branches, since this would affect attempts
to build any of them on recent NetBSD.
Thomas Munro
It appears that we can no longer get away with using V0 call convention
for bool-returning functions in newer versions of MSVC. The compiler
seems to generate code that doesn't clear the higher-order bits of the
result register, causing the bool result Datum to often read as "true"
when "false" was intended. This is not very surprising, since the
function thinks it's returning a bool-width result but fmgr_oldstyle
assumes that V0 functions return "char *"; what's surprising is that
that hack worked for so long on so many platforms.
The only functions of this description in core+contrib are in contrib/seg,
which we'd intentionally left mostly in V0 style to serve as a warning
canary if V0 call convention breaks. We could imagine hacking things
so that they're still V0 (we'd have to redeclare the bool-returning
functions as returning some suitably wide integer type, like size_t,
at the C level). But on the whole it seems better to convert 'em to V1.
We can still leave the pointer- and int-returning functions in V0 style,
so that the test coverage isn't gone entirely.
Back-patch to 9.5, since our intention is to support VS2015 in 9.5
and later. There's no SQL-level change in the functions' behavior
so back-patching should be safe enough.
Discussion: <22094.1461273324@sss.pgh.pa.us>
Michael Paquier, adjusted some by me
The implementation of that feature involves injecting nodes into the
raw parsetree where explicit parentheses appear. Various places in
parse_expr.c that test to see "is this child node of type Foo" need to
look through such nodes, else we'll get different behavior when
operator_precedence_warning is on than when it is off. Note that we only
need to handle this when testing untransformed child nodes, since the
AEXPR_PAREN nodes will be gone anyway after transformExprRecurse.
Per report from Scott Ribe and additional code-reading. Back-patch
to 9.5 where this feature was added.
Report: <ED37E303-1B0A-4CD8-8E1E-B9C4C2DD9A17@elevated-dev.com>
Given a left join containing a full join in its righthand side, with
the left join's joinclause referencing only one side of the full join
(in a non-strict fashion, so that the full join doesn't get simplified),
the planner could fail with "failed to build any N-way joins" or related
errors. This happened because the full join was seen as overlapping the
left join's RHS, and then recent changes within join_is_legal() caused
that function to conclude that the full join couldn't validly be formed.
Rather than try to rejigger join_is_legal() yet more to allow this,
I think it's better to fix initsplan.c so that the required join order
is explicit in the SpecialJoinInfo data structure. The previous coding
there essentially ignored full joins, relying on the fact that we don't
flatten them in the joinlist data structure to preserve their ordering.
That's sufficient to prevent a wrong plan from being formed, but as this
example shows, it's not sufficient to ensure that the right plan will
be formed. We need to work a bit harder to ensure that the right plan
looks sane according to the SpecialJoinInfos.
Per bug #14105 from Vojtech Rylko. This was apparently induced by
commit 8703059c6 (though now that I've seen it, I wonder whether there
are related cases that could have failed before that); so back-patch
to all active branches. Unfortunately, that patch also went into 9.0,
so this bug is a regression that won't be fixed in that branch.
The coverage was rather lean for cases that bind() or listen() might
return. Add entries for everything that there's a direct equivalent
for in the set of Unix errnos that elog.c has heard of.
There's no longer a need for the MSVC-version-specific code stanza that
forcibly redefines errno code symbols, because since commit 73838b52 we're
unconditionally redefining them in the stanza before this one anyway.
Now it's merely confusing and ugly, so get rid of it; and improve the
comment that explains what's going on here.
Although this is just cosmetic, back-patch anyway since I'm intending
to back-patch some less-cosmetic changes in this same hunk of code.
Tom Lane