Peter Eisentraut [Thu, 18 May 2017 18:16:16 +0000 (14:16 -0400)]
Fix table syncing with different column order
Logical replication supports replicating between tables with different
column order. But this failed for the initial table sync because of a
logic error in how the column list for the internal COPY command was
composed. Fix that and also add a test.
Also fix a minor omission in the column name mapping cache. When
creating the mapping list, it would not skip locally dropped columns.
So if a remote column had the same name as a locally dropped
column (...pg.dropped...), then the expected error would not occur.
Peter Eisentraut [Wed, 24 May 2017 22:56:21 +0000 (18:56 -0400)]
Improve logical replication worker log messages
Reduce some redundant messages to DEBUG1. Be clearer about the
distinction between apply workers and table synchronization workers.
Add subscription and table name where possible.
Tom Lane [Wed, 24 May 2017 19:28:34 +0000 (15:28 -0400)]
Tighten checks for whitespace in functions that parse identifiers etc.
This patch replaces isspace() calls with scanner_isspace() in functions
that are likely to be presented with non-ASCII input. isspace() has
the small advantage that it will correctly recognize no-break space
in single-byte encodings (such as LATIN1); but it cannot work successfully
for any multibyte character, and depending on platform it might return
false positive results for some fragments of multibyte characters. That's
disastrous for functions that are trying to discard whitespace between
valid strings, as noted in bug #14662 from Justin Muise. Even treating
no-break space as whitespace is pretty questionable for the usages touched
here, because the core scanner would think it is an identifier character.
Affected functions are parse_ident(), parseNameAndArgTypes (underlying
regprocedurein() and siblings), SplitIdentifierString (used for parsing
GUCs and options that are qualified names or lists of names), and
SplitDirectoriesString (used for parsing GUCs that are lists of
directories).
All the functions adjusted here are parsing SQL identifiers and similar
constructs, so it's reasonable to insist that their definition of
whitespace match the core scanner. So we can hope that this won't cause
many backwards-compatibility problems. I've left alone isspace() calls
in places that aren't really expecting any non-ASCII input characters,
such as float8in().
Verify that the server constructed the SCRAM nonce correctly.
The nonce consists of client and server nonces concatenated together. The
client checks the nonce contained the client nonce, but it would get fooled
if the server sent a truncated or even empty nonce.
Reported by Steven Fackler to security@postgresql.org. Neither me or Steven
are sure what harm a malicious server could do with this, but let's fix it.
Tom Lane [Sun, 21 May 2017 17:05:16 +0000 (13:05 -0400)]
Fix precision and rounding issues in money multiplication and division.
The cash_div_intX functions applied rint() to the result of the division.
That's not merely useless (because the result is already an integer) but
it causes precision loss for values larger than 2^52 or so, because of
the forced conversion to float8.
On the other hand, the cash_mul_fltX functions neglected to apply rint() to
their multiplication results, thus possibly causing off-by-one outputs.
Per C standard, arithmetic between any integral value and a float value is
performed in float format. Thus, cash_mul_flt4 and cash_div_flt4 produced
answers good to only about six digits, even when the float value is exact.
We can improve matters noticeably by widening the float inputs to double.
(It's tempting to consider using "long double" arithmetic if available,
but that's probably too much of a stretch for a back-patched fix.)
Also, document that cash_div_intX operators truncate rather than round.
Per bug #14663 from Richard Pistole. Back-patch to all supported branches.
Tom Lane [Sun, 21 May 2017 15:46:04 +0000 (11:46 -0400)]
Fix contrib/sepgsql regression tests for partition NOT NULL change.
Commit 3ec76ff1f changed the partitioning logic to not install a forced
NOT NULL constraint on range partitioning columns. This affects the
expected output for contrib/sepgsql, because there's no longer LOG
entries reporting allowance of such a constraint. Per buildfarm.
Tom Lane [Fri, 19 May 2017 22:05:20 +0000 (18:05 -0400)]
Rethink flex flags for syncrep_scanner.l.
Using flex's -i switch to achieve case-insensitivity is not a very safe
practice, because the scanner's behavior may then depend on the locale
that flex was invoked in. In the particular example at hand, that's
not academic: the possible matches for "FIRST" will be different in a
Turkish locale than elsewhere. Do it the hard way instead, as our
other scanners do.
Also, drop use of -b -CF -p, because this scanner is only used when
parsing the contents of a GUC variable. That's not done often, and
the amount of text to be parsed can be expected to be trivial, so
prioritizing scanner speed over code size seems like quite the wrong
tradeoff. Using flex's default optimization options reduces the
size of syncrep_gram.o by more than 50%.
The case-insensitivity problem is new in HEAD (cf commit 3901fd70c).
The poor choice of optimization flags exists also in 9.6, but it doesn't
seem important enough to back-patch.
Robert Haas [Fri, 19 May 2017 20:49:38 +0000 (16:49 -0400)]
pg_upgrade: Handle hash index upgrades more smoothly.
Mark any old hash indexes as invalid so that they don't get used, and
create a script to run REINDEX on all of them. Without this, we'd
still try to use any upgraded hash indexes, but it would fail.
Amit Kapila, reviewed by me. Per a suggestion from Tom Lane.
Robert Haas [Fri, 19 May 2017 19:02:16 +0000 (15:02 -0400)]
Fix corruption of tableElts list by MergeAttributes().
Since commit e7b3349a8ad7afaad565c573fbd65fb46af6abbe, MergeAttributes
destructively modifies the input List, to which the caller's
CreateStmt still points. One may wonder whether this was already a
bug, but commit f0e44751d7175fa3394da2c8f85e3ceb3cdbfe63 made things
noticeably worse by adding additional destructive modifications so
that the caller's List might, in the case of creation a partitioned
table, no longer even be structurally valid. Restore the status quo
ante by assigning the return value of MergeAttributes back to
stmt->tableElts in the caller.
In most of the places where DefineRelation is called, it doesn't
matter what stmt->tableElts points to here or whether it's valid or
not, because the caller doesn't use the statement for anything after
DefineRelation returns anyway. However, ProcessUtilitySlow passes it
to EventTriggerCollectSimpleCommand, and that function tries to invoke
copyObject on it. If any of the CreateStmt's substructure is invalid
at that point, undefined behavior will result.
One might wonder whether this whole area needs further revision -
perhaps DefineRelation() ought not to be destructively modifying the
caller-provided CreateStmt at all. However, that would be a behavior
change for any event triggers using C code to inspect the CreateStmt,
so for now, just fix the crash.
Report by Amit Langote, who provided a somewhat different patch for it.
Robert Haas [Thu, 18 May 2017 17:48:10 +0000 (13:48 -0400)]
Don't explicitly mark range partitioning columns NOT NULL.
This seemed like a good idea originally because there's no way to mark
a range partition as accepting NULL, but that now seems more like a
current limitation than something we want to lock down for all time.
For example, there's a proposal to add the notion of a default
partition which accepts all rows not otherwise routed, which directly
conflicts with the idea that a range-partitioned table should never
allow nulls anywhere. So let's change this while we still can, by
putting the NOT NULL test into the partition constraint instead of
changing the column properties.
Amit Langote and Robert Haas, reviewed by Amit Kapila
Peter Eisentraut [Thu, 18 May 2017 00:47:37 +0000 (20:47 -0400)]
Improve CREATE SUBSCRIPTION option parsing
When creating a subscription with slot_name = NONE, we failed to check
that also create_slot = false and enabled = false were set. This
created an invalid subscription and could later lead to a crash if a
NULL slot name was accessed. Add more checks around that for
robustness.
Robert Haas [Wed, 17 May 2017 18:31:48 +0000 (14:31 -0400)]
Code review for make_partition_op_expr.
It's better to use the actual keynum here rather than 0, because
someday someone might try to make list partitioning work with
multiple partitioning columns.
Tom Lane [Wed, 17 May 2017 17:04:03 +0000 (13:04 -0400)]
Revert changes to pg_basebackup and pg_waldump usage() code.
Partially revert commit c079673dcb7f210617c9fc1470e6bf166d8a2971.
There were complaints that splitting switch descriptions would
complicate translation efforts. There are probably ways to resolve
the formatting problem without doing that, but undo it while we're
discussing.
Tom Lane [Wed, 17 May 2017 16:24:19 +0000 (12:24 -0400)]
Make psql handle EOF during COPY FROM STDIN properly on all platforms.
When stdin is a terminal, it's possible to end a COPY FROM STDIN with
a keyboard EOF signal (typically control-D), and then keep on issuing
SQL commands. One would expect another COPY FROM STDIN to work as well,
but on some platforms it did not. This turns out to be because we were
not resetting the stream's feof() flag, and BSD-ish versions of fread()
and fgets() won't attempt to read more data if that's set.
The misbehavior is observed on BSDen (including macOS), but not Linux,
Windows, or SysV-ish Unixen, which makes this a portability bug not
just a missing feature.
Add a clearerr() call to fix the behavior, and improve the prompt that's
issued when copying from a TTY to mention that EOF signals work.
It's been like this forever, so back-patch to all supported branches.
Peter Eisentraut [Wed, 17 May 2017 02:57:16 +0000 (22:57 -0400)]
Check relkind of tables in CREATE/ALTER SUBSCRIPTION
We used to only check for a supported relkind on the subscriber during
replication, which is needed to ensure that the setup is valid and we
don't crash. But it's also useful to tell the user immediately when
CREATE or ALTER SUBSCRIPTION is executed that the relation being added
to the subscription is not of a supported relkind.
Author: Petr Jelinek <petr.jelinek@2ndquadrant.com> Reported-by: tushar <tushar.ahuja@enterprisedb.com>
Tom Lane [Wed, 17 May 2017 00:36:35 +0000 (20:36 -0400)]
Preventive maintenance in advance of pgindent run.
Reformat various places in which pgindent will make a mess, and
fix a few small violations of coding style that I happened to notice
while perusing the diffs from a pgindent dry run.
There is one actual bug fix here: the need-to-enlarge-the-buffer code
path in icu_convert_case was obviously broken. Perhaps it's unreachable
in our usage? Or maybe this is just sadly undertested.
Tom Lane [Tue, 16 May 2017 23:33:31 +0000 (19:33 -0400)]
Fix leakage of memory context header in find_all_inheritors().
Commit 827d6f977 contained the same misunderstanding of hash_create's API
as commit 090010f2e. As in 5d00b764c, remove the unnecessary layer of
memory context. (This bug is less significant than the other one, since
the extra context would be under a relatively short-lived context, but
it's still a bug.)
Tom Lane [Tue, 16 May 2017 19:24:52 +0000 (15:24 -0400)]
Try to ensure that stats collector's receive buffer size is at least 100KB.
Since commit 4e37b3e15, buildfarm member frogmouth has been failing
occasionally with symptoms indicating that some expected stats data is
getting dropped. The reason that that commit changed the behavior seems
probably to be that more data is getting shoved at the collector in a short
span of time. In current sources, the stats test's first session sends
about 9KB of data while exiting, which is probably the same as what was
sent just before wait_for_stats() in the previous test design. But now,
the test's second session is starting up concurrently, and it sends another
2KB (presumably reflecting its initial catalog accesses). Since frogmouth
is running on Windows XP, which reputedly has a default socket receive
buffer size of only 8KB, it is not very surprising if this has put us over
the threshold where the receive buffer can overflow and drop messages.
The same mechanism could very easily explain the intermittent stats test
failures we've been seeing for years, since background processes such
as the bgwriter will sometimes send data concurrently with all this, and
could thus cause occasional buffer overflows.
Hence, insert some code into pgstat_init() to increase the stats socket's
receive buffer size to 100KB if it's less than that. (On failure, emit a
LOG message, but keep going.) Modern systems seem to have default sizes
in the range of 100KB-250KB, but older platforms don't. I couldn't find
any platforms that wouldn't accept 100KB, so in theory this won't cause
any portability problems.
If this is successful at reducing the buildfarm failure rate in HEAD,
we should back-patch it, because it's certain that similar buffer overflows
happen in the field on platforms with small buffer sizes. Going forward,
there might be an argument for trying to increase the buffer size even
more, but let's take a baby step first.
Tom Lane [Tue, 16 May 2017 03:27:51 +0000 (23:27 -0400)]
In SSL tests, don't scribble on permissions of a repo file.
Modifying the permissions of a persistent file isn't really much nicer
than modifying its contents, even if git doesn't currently notice it.
Adjust the test script to make a copy and set the permissions of that
instead.
Michael Paquier, per a gripe from me. Back-patch to 9.5 where these
tests were introduced.
Tom Lane [Mon, 15 May 2017 15:33:44 +0000 (11:33 -0400)]
Fix unsafe reference into relcache in constructed CommentStmt.
The CommentStmt made by RebuildConstraintComment() has to pstrdup the
relation name, else it will contain a dangling pointer after that
relcache entry is flushed. (I'm less sure that pstrdup'ing conname
is necessary, but let's be safe.) Failure to do this leads to weird
errors or crashes, as reported by Marko Elezovic.
Bug introduced by commit e42375fc8, so back-patch to 9.5 as that was.
Fix by David Rowley, regression test by Michael Paquier
Peter Eisentraut [Wed, 10 May 2017 03:35:31 +0000 (23:35 -0400)]
Fix ALTER SEQUENCE locking
In 1753b1b027035029c2a2a1649065762fafbf63f3, the pg_sequence system
catalog was introduced. This made sequence metadata changes
transactional, while the actual sequence values are still behaving
nontransactionally. This requires some refinement in how ALTER
SEQUENCE, which operates on both, locks the sequence and the catalog.
The main problems were:
- Concurrent ALTER SEQUENCE causes "tuple concurrently updated" error,
caused by updates to pg_sequence catalog.
- Sequence WAL writes and catalog updates are not protected by same
lock, which could lead to inconsistent recovery order.
- nextval() disregarding uncommitted ALTER SEQUENCE changes.
To fix, nextval() and friends now lock the sequence using
RowExclusiveLock instead of AccessShareLock. ALTER SEQUENCE locks the
sequence using ShareRowExclusiveLock. This means that nextval() and
ALTER SEQUENCE block each other, and ALTER SEQUENCE on the same sequence
blocks itself. (This was already the case previously for the OWNER TO,
RENAME, and SET SCHEMA variants.) Also, rearrange some code so that the
entire AlterSequence is protected by the lock on the sequence.
As an exception, use reduced locking for ALTER SEQUENCE ... RESTART.
Since that is basically a setval(), it does not require the full locking
of other ALTER SEQUENCE actions. So check whether we are only running a
RESTART and run with less locking if so.
Reviewed-by: Michael Paquier <michael.paquier@gmail.com> Reported-by: Jason Petersen <jason@citusdata.com> Reported-by: Andres Freund <andres@anarazel.de>
Tom Lane [Mon, 15 May 2017 03:33:03 +0000 (23:33 -0400)]
stats regression test's wait_for_stats() must check timestamp too.
pg_stat_get_snapshot_timestamp() returns the timestamp seen in the "global"
stats file. Because pgstat_write_statsfiles() writes per-DB stats files
before the global file (or at least before renaming it into place), there
is a window where the test backend can see all the stats updates that
wait_for_stats() was checking for (all of which come from the per-DB file)
but also see the same global stats file it had seen at the start of the
test script. This results in a failure in only the "snapshot_newer" query,
as reported by a couple of buildfarm members recently.
I suspect that this ought to be back-patched. Commit 4e37b3e15 has
evidently increased the probability of this window getting hit, but
it's not apparent why it could not have been hit before. I'll refrain
for the moment though.
Fix cases where an elog(ERROR) partway through a function would leave the
persistent data structures in a corrupt state. pgstat_report_stat got this
wrong by invalidating PgStat_TableEntry structs before removing hashtable
entries pointing to them, and get_tabstat_entry got it wrong by ignoring
the possibility of palloc failure after it had already created a hashtable
entry.
Also, avoid leaking a memory context per transaction, which the previous
code did through misunderstanding hash_create's API. We do not need to
create a context to hold the hash table; hash_create will do that.
(The leak wasn't that large, amounting to only a memory context header
per iteration, but it's still surprising that nobody noticed it yet.)
Tom Lane [Mon, 15 May 2017 01:39:10 +0000 (21:39 -0400)]
Make stats regression test more robust in the face of parallel query.
Commit 60690a6fe attempted to fix the wait_for_stats() function in this
test so that it would wait properly if the tenk2 scans were done in
parallel workers instead of the main session (typically as a consequence of
force_parallel_mode being turned on). However, we made it test for whether
the main session's actions had been reported by looking for inserts on
'trunc_stats_test'. This is the Wrong Thing, because those aren't the last
updates we expect the main session to do. As shown by recent failures on
buildfarm member frogmouth, it's entirely likely that the trunc_stats_test
updates will be reported in a separate message from later updates, which
means there can be a window in which wait_for_stats() will exit but not all
the updates we are expecting to see will have arrived. We should test for
the last updates we're expecting, namely those on 'trunc_stats_test4'.
Unfortunately, I doubt that this explains frogmouth's failures, because
there's no reason to believe that it's running the tenk2 queries in
parallel. Still, the test is wrong on its own terms, so fix and back-patch
to 9.6 where parallel query came in.
Robert Haas [Mon, 15 May 2017 00:59:28 +0000 (20:59 -0400)]
Attempt to fix compiler warning.
Per a report from Tom Lane, newer versions of gcc apparently think
that partexprs_item_saved can be used uninitialized. Try to convince
them otherwise.
Tom Lane [Sun, 14 May 2017 17:32:59 +0000 (13:32 -0400)]
Fix maintenance hazards caused by ill-considered use of default: cases.
Remove default cases from assorted switches over ObjectClass and some
related enum types, so that we'll get compiler warnings when someone
adds a new enum value without accounting for it in all these places.
In passing, re-order some switch cases as needed to match the declaration
of enum ObjectClass. OK, that's just neatnik-ism, but I dislike code
that looks like it was assembled with the help of a dartboard.
Tom Lane [Sun, 14 May 2017 16:22:16 +0000 (12:22 -0400)]
Fix handling of extended statistics during ALTER COLUMN TYPE.
ALTER COLUMN TYPE on a column used by a statistics object fails since
commit 928c4de30, because the relevant switch in ATExecAlterColumnType
is unprepared for columns to have dependencies from OCLASS_STATISTIC_EXT
objects.
Although the existing types of extended statistics don't actually need us
to do any work for a column type change, it seems completely indefensible
that that assumption is hidden behind the failure of an unrelated module
to contain any code for the case. Hence, create and call an API function
in statscmds.c where the assumption can be explained, and where we could
add code to deal with the problem when it inevitably becomes real.
Also, the reason this wasn't handled before, neither for extended stats
nor for the last half-dozen new OCLASS kinds :-(, is that the default:
in that switch suppresses compiler warnings, allowing people to miss the
need to consider it when adding an OCLASS. We don't really need a default
because surely getObjectClass should only return valid values of the enum;
so remove it, and add the missed OCLASS entries where they should be.
Tom Lane [Sun, 14 May 2017 14:54:47 +0000 (10:54 -0400)]
Standardize terminology for pg_statistic_ext entries.
Consistently refer to such an entry as a "statistics object", not just
"statistics" or "extended statistics". Previously we had a mismash of
terms, accompanied by utter confusion as to whether the term was
singular or plural. That's not only grating (at least to the ear of
a native English speaker) but could be outright misleading, eg in error
messages that seemed to be referring to multiple objects where only one
could be meant.
This commit fixes the code and a lot of comments (though I may have
missed a few). I also renamed two new SQL functions,
pg_get_statisticsextdef -> pg_get_statisticsobjdef
pg_statistic_ext_is_visible -> pg_statistics_obj_is_visible
to conform better with this terminology.
I have not touched the SGML docs other than fixing those function
names; the docs certainly need work but it seems like a separable task.
Andrew Dunstan [Sun, 14 May 2017 05:10:18 +0000 (01:10 -0400)]
Suppress indentation from Data::Dumper in regression tests
Ultra-modern versions of the perl Data::Dumper module have apparently
changed how they indent output. Instead of trying to keep up we choose
to tell it to supporess all indentation in the hstore_plperl regression
tests.
Backpatch to 9.5 where this feature was introduced.
Andres Freund [Sat, 13 May 2017 21:47:41 +0000 (14:47 -0700)]
Avoid superfluous work for commits during logical slot creation.
Before 955a684e0401 logical decoding snapshot maintenance needed to
cope with transactions it might not have seen in their entirety. For
such transactions we'd to assume they modified the catalog (could have
happened before we were watching), and thus a new snapshot had to be
built, and distributed to concurrently running transactions.
That's problematic because building a new snapshot isn't that cheap ,
especially as the the array of committed transactions needs to be
sorted. When creating a slot on a server with a lot of transactions,
this could make logical slot creation infeasibly expensive.
After 955a684e0401 there's no need to deal with transaction that
aren't guaranteed to be fully observable. That allows to avoid
building snapshots for transactions that haven't modified catalog,
even before reaching consistency.
While this isn't necessarily a bugfix, slot creation being impossible
in some production workloads, is severe enough to warrant
backpatching.
Author: Andres Freund, based on a quite different patch from Petr Jelinek Analyzed-By: Petr Jelinek Reviewed-By: Petr Jelinek
Discussion: https://postgr.es/m/f37e975c-908f-858e-707f-058d3b1eb214@2ndquadrant.com
Backpatch: 9.4-, where logical decoding has been introduced
Andres Freund [Sat, 13 May 2017 21:21:00 +0000 (14:21 -0700)]
Fix race condition leading to hanging logical slot creation.
The snapshot assembly during the creation of logical slots relied
waiting for transactions in xl_running_xacts to end, by checking for
their commit/abort records. Unfortunately, despite locking, it is
possible to see an xl_running_xact record listing transactions as
ready, that have already WAL-logged an commit/abort record, as the
locking just prevents the ProcArray to be adjusted, and the commit
record has to be logged first.
That lead to either delayed or hanging snapshot creation, because
snapbuild.c would wait "forever" to see commit/abort records for some
transactions. That hang resolved only if a xl_running_xacts record
without any running transactions happened to be logged, far from
certain on a busy server.
It's impractical to prevent that via more heavyweight locking, the
likelihood of deadlocks and significantly increased contention would
be too big.
Instead change the initial snapshot creation to be solely based on
tracking the oldest running transaction via
xl_running_xacts->oldestRunningXid - that actually ends up
significantly simplifying the code. That has two disadvantages:
1) Because we cannot fully "trust" the contents of xl_running_xacts,
we cannot use it to build the initial snapshot. Instead we have to
wait twice for all running transactions to finish.
2) Previously a slot, unless the race occurred, could be created when
the all transaction perceived as running based on commit/abort
records, now we have to wait for the next xl_running_xacts record.
To address that, trigger logging new xl_running_xacts record from
within snapbuild.c exactly when necessary.
Unfortunately snabuild.c's SnapBuild is stored on disk, one of the
stupider ideas of a certain Mr Freund, so we can't change it in a
minor release. As this is going to be backpatched, we have to hack
around a bit to keep on-disk compatibility. A later commit will
rejigger that on master.
Author: Andres Freund, based on a quite different patch from Petr Jelinek Analyzed-By: Petr Jelinek Reviewed-By: Petr Jelinek
Discussion: https://postgr.es/m/f37e975c-908f-858e-707f-058d3b1eb214@2ndquadrant.com
Backpatch: 9.4-, where logical decoding has been introduced
Tom Lane [Sat, 13 May 2017 19:14:39 +0000 (15:14 -0400)]
Redesign get_attstatsslot()/free_attstatsslot() for more safety and speed.
The mess cleaned up in commit da0759600 is clear evidence that it's a
bug hazard to expect the caller of get_attstatsslot()/free_attstatsslot()
to provide the correct type OID for the array elements in the slot.
Moreover, we weren't even getting any performance benefit from that,
since get_attstatsslot() was extracting the real type OID from the array
anyway. So we ought to get rid of that requirement; indeed, it would
make more sense for get_attstatsslot() to pass back the type OID it found,
in case the caller isn't sure what to expect, which is likely in binary-
compatible-operator cases.
Another problem with the current implementation is that if the stats array
element type is pass-by-reference, we incur a palloc/memcpy/pfree cycle
for each element. That seemed acceptable when the code was written because
we were targeting O(10) array sizes --- but these days, stats arrays are
almost always bigger than that, sometimes much bigger. We can save a
significant number of cycles by doing one palloc/memcpy/pfree of the whole
array. Indeed, in the now-probably-common case where the array is toasted,
that happens anyway so this method is basically free. (Note: although the
catcache code will inline any out-of-line toasted values, it doesn't
decompress them. At the other end of the size range, it doesn't expand
short-header datums either. In either case, DatumGetArrayTypeP would have
to make a copy. We do end up using an extra array copy step if the element
type is pass-by-value and the array length is neither small enough for a
short header nor large enough to have suffered compression. But that
seems like a very acceptable price for winning in pass-by-ref cases.)
Hence, redesign to take these insights into account. While at it,
convert to an API in which we fill a struct rather than passing a bunch
of pointers to individual output arguments. That will make it less
painful if we ever want further expansion of what get_attstatsslot can
pass back.
It's certainly arguable that this is new development and not something to
push post-feature-freeze. However, I view it as primarily bug-proofing
and therefore something that's better to have sooner not later. Since
we aren't quite at beta phase yet, let's put it in.
Tom Lane [Sat, 13 May 2017 13:42:12 +0000 (09:42 -0400)]
Avoid hard-wired sleep delays in stats regression test.
On faster machines, the overall runtime for running the core regression
tests is under twenty seconds these days, of which the hard-wired delays
in the stats test are a significant fraction. But on closer inspection,
it seems like we shouldn't need those.
The initial 2-second delay is there only to reduce the risk of the test's
stats messages not getting sent due to contention. But analysis of the
last ten years' worth of buildfarm runs shows no evidence that such
failures actually occur. (We do see failures that look like stats
messages not getting sent, particularly on Windows; but there is little
reason to believe that the initial delay reduces their frequency.)
The later 1-second delay is there to ensure that our session's stats
will have gotten sent. But we could also do that by starting a fresh
session, which takes well under 1 second even on very slow machines.
Hence, let's remove both delays and see what happens. The first delay
was the only test of pg_sleep_for() in the regression tests, but we can
move that responsibility into wait_for_stats().
Alvaro Herrera [Sat, 13 May 2017 04:05:48 +0000 (01:05 -0300)]
Complete tab completion for DROP STATISTICS
Tab-completing DROP STATISTICS would only work if you started writing
the schema name containing the statistics object, because the visibility
clause was missing. To add it, we need to add SQL-callable support for
testing visibility of a statistics object, like all other object types
already have.
Tom Lane [Fri, 12 May 2017 23:05:13 +0000 (19:05 -0400)]
Avoid searching for callback functions in CallSyscacheCallbacks().
We have now grown enough registerable syscache-invalidation callback
functions that the original assumption that there would be few of them
is causing performance problems. In particular, let's fix things so that
CallSyscacheCallbacks doesn't have to search the whole array to find
which callback(s) to invoke for a given cache ID. Preserve the original
behavior that callbacks are called in order of registration, just in
case there's someplace that depends on that (which I doubt).
In support of this, export the number of syscaches from syscache.h.
People could have found that out anyway from the enum, but adding a
#define makes that much safer.
This provides a useful additional speedup in Mathieu Fenniak's
logical-decoding test case, although we're reaching the point of
diminishing returns there. I think any further improvement will have
to come from reducing the number of cache invalidations that are
triggered in the first place. Still, we can hope that this change
gives some incremental benefit for all invalidation scenarios.
Back-patch to 9.4 where logical decoding was introduced.
Tom Lane [Fri, 12 May 2017 22:30:02 +0000 (18:30 -0400)]
Reduce initial size of RelfilenodeMapHash.
A test case provided by Mathieu Fenniak shows that hash_seq_search'ing
this hashtable can consume a very significant amount of overhead during
logical decoding, which triggers frequent cache invalidation. Testing
suggests that the actual population of the hashtable is often no more
than a few dozen entries, so we can cut the overhead just by dropping
the initial number of buckets down from 1024 --- I chose to cut it to 64.
(In situations where we do have a significant number of entries, we
shouldn't get any real penalty from doing this, as the dynahash.c code
will resize the hashtable automatically.)
This gives a further factor-of-two savings in Mathieu's test case.
That may be overly optimistic for real-world benefit, as real cases
may have larger average table populations, but it's hard to see it
turning into a net negative for any workload.
Back-patch to 9.4 where relfilenodemap.c was introduced.
Remove the "default:" clause in the switch, to avoid this problem in the
future. Other switches involving the same enum should probably be
changed in the same way, but are not touched by this patch.
Tom Lane [Fri, 12 May 2017 22:17:29 +0000 (18:17 -0400)]
Avoid searching for the target catcache in CatalogCacheIdInvalidate.
A test case provided by Mathieu Fenniak shows that the initial search for
the target catcache in CatalogCacheIdInvalidate consumes a very significant
amount of overhead in cases where cache invalidation is triggered but has
little useful work to do. There is no good reason for that search to exist
at all, as the index array maintained by syscache.c allows direct lookup of
the catcache from its ID. We just need a frontend function in syscache.c,
matching the division of labor for most other cache-accessing operations.
While there's more that can be done in this area, this patch alone reduces
the runtime of Mathieu's example by 2X. We can hope that it offers some
useful benefit in other cases too, although usually cache invalidation
overhead is not such a striking fraction of the total runtime.
Back-patch to 9.4 where logical decoding was introduced. It might be
worth going further back, but presently the only case we know of where
cache invalidation is really a significant burden is in logical decoding.
Also, older branches have fewer catcaches, reducing the possible benefit.
(Note: although this nominally changes catcache's API, we have always
documented CatalogCacheIdInvalidate as a private function, so I would
have little sympathy for an external module calling it directly. So
backpatching should be fine.)
Tom Lane [Fri, 12 May 2017 20:26:31 +0000 (16:26 -0400)]
Fix dependencies for extended statistics objects.
A stats object ought to have a dependency on each individual column
it reads, not the entire table. Doing this honestly lets us get rid
of the hard-wired logic in RemoveStatisticsExt, which seems to have
been misguidedly modeled on RemoveStatistics; and it will be far easier
to extend to multiple tables later.
Also, add overlooked dependency on owner, and make the dependency on
schema be NORMAL like every other such dependency.
There remains some unfinished work here, which is to allow statistics
objects to be extension members. That takes more effort than just
adding the dependency call, though, so I left it out for now.
initdb forced because this changes the set of pg_depend records that
should exist for a statistics object.
Alvaro Herrera [Fri, 12 May 2017 17:59:23 +0000 (14:59 -0300)]
Change CREATE STATISTICS syntax
Previously, we had the WITH clause in the middle of the command, where
you'd specify both generic options as well as statistic types. Few
people liked this, so this commit changes it to remove the WITH keyword
from that clause and makes it accept statistic types only. (We
currently don't have any generic options, but if we invent in the
future, we will gain a new WITH clause, probably at the end of the
command).
Also, the column list is now specified without parens, which makes the
whole command look more similar to a SELECT command. This change will
let us expand the command to supporting expressions (not just columns
names) as well as multiple tables and their join conditions.
Tom added lots of code comments and fixed some parts of the CREATE
STATISTICS reference page, too; more changes in this area are
forthcoming. He also fixed a potential problem in the alter_generic
regression test, reducing verbosity on a cascaded drop to avoid
dependency on message ordering, as we do in other tests.
Tom also closed a security bug: we documented that table ownership was
required in order to create a statistics object on it, but didn't
actually implement it.
Implement tab-completion for statistics objects. This can stand some
more improvement.
Authors: Alvaro Herrera, with lots of cleanup by Tom Lane
Discussion: https://postgr.es/m/20170420212426.ltvgyhnefvhixm6i@alvherre.pgsql
Andrew Dunstan [Fri, 12 May 2017 15:11:49 +0000 (11:11 -0400)]
Honor PROVE_FLAGS environment setting
On MSVC builds and on back branches that means removing the hardcoded
--verbose setting. On master for Unix that means removing the empty
setting in the global Makefile so that the value can be acquired from
the environment as well as from the make arguments.
Andrew Dunstan [Fri, 12 May 2017 14:17:54 +0000 (10:17 -0400)]
Add libxml2 include path for MSVC builds
On Unix this path is detected via the use of xml2-config, but that's not
available on Windows. This means that users building with libxml2 will
no longer need to move things around from the standard libxml2
installation for MSVC builds.
Andrew Dunstan [Fri, 12 May 2017 10:41:23 +0000 (06:41 -0400)]
Avoid tests which crash the calling process on Windows
Certain recovery tests use the Perl IPC::Run module's start/kill_kill
method of processing. On at least some versions of perl this causes the
whole process and its caller to crash. If we ever find a better way of
doing these tests they can be re-enabled on this platform. This does not
affect Mingw or Cygwin builds, which use a different perl and a
different shell and so are not affected.
projects / postgresql / log