Alvaro Herrera [Wed, 18 Oct 2017 11:29:16 +0000 (13:29 +0200)]
Make OWNER TO subcommand mention consistent
We say 'OWNER TO' in the synopsis; let's use that form elsewhere.
There is a paragraph in the <note> section that refers to various
subcommands very loosely (including OWNER); I didn't think it was an
improvement to change that one.
This is a fairly inconsequential change, so no backpatch.
Author: Amit Langote
Discussion: https://postgr.es/m/69ec7b51-03e5-f523-95ce-c070ee790e70@lab.ntt.co.jp
For DocBook XML compatibility, don't use SGML empty tags (</>) anymore,
replace by the full tag name. Add a warning option to catch future
occurrences.
Tom Lane [Mon, 16 Oct 2017 21:56:42 +0000 (17:56 -0400)]
Fix incorrect handling of CTEs and ENRs as DML target relations.
setTargetTable threw an error if the proposed target RangeVar's relname
matched any visible CTE or ENR. This breaks backwards compatibility in
the CTE case, since pre-v10 we never looked for a CTE here at all, so that
CTE names did not mask regular tables. It does seem like a good idea to
throw an error for the ENR case, though, thus causing ENRs to mask tables
for this purpose; ENRs are new in v10 so we're not breaking existing code,
and we may someday want to allow them to be the targets of DML.
To fix that, replace use of getRTEForSpecialRelationTypes, which was
overkill anyway, with use of scanNameSpaceForENR.
A second problem was that the check neglected to verify null schemaname,
so that a CTE or ENR could incorrectly be thought to match a qualified
RangeVar. That happened because getRTEForSpecialRelationTypes relied
on its caller to have checked for null schemaname. Even though the one
remaining caller got it right, this is obviously bug-prone, so move
the check inside getRTEForSpecialRelationTypes.
Also, revert commit 18ce3a4ab's extremely poorly thought out decision to
add a NULL return case to parserOpenTable --- without either documenting
that or adjusting any of the callers to check for it. The current bug
seems to have arisen in part due to working around that bad idea.
In passing, remove the one-line shim functions transformCTEReference and
transformENRReference --- they don't seem to be adding any clarity or
functionality.
Per report from Hugo Mercier (via Julien Rouhaud). Back-patch to v10
where the bug was introduced.
Peter Eisentraut [Fri, 11 Aug 2017 03:33:47 +0000 (23:33 -0400)]
Exclude flex-generated code from coverage testing
Flex generates a lot of functions that are not actually used. In order
to avoid coverage figures being ruined by that, mark up the part of the
.l files where the generated code appears by lcov exclusion markers.
That way, lcov will typically only reported on coverage for the .l file,
which is under our control, but not for the .c file.
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
Tom Lane [Mon, 16 Oct 2017 20:02:51 +0000 (16:02 -0400)]
Treat aggregate direct arguments as per-agg data not per-trans data.
There is no reason to insist that direct arguments must match before
we can merge transition states of two aggregate calls. They're only
used during the finalfn call, so we can treat them as like the finalfn
itself. This allows, eg, merging of
select
percentile_cont(0.25) within group (order by a),
percentile_disc(0.5) within group (order by a)
from ...
This didn't matter (and could not have been tested) before we allowed
state merging of OSAs otherwise.
Tom Lane [Mon, 16 Oct 2017 19:51:23 +0000 (15:51 -0400)]
Allow the built-in ordered-set aggregates to share transition state.
The built-in OSAs all share the same transition function, so they can
share transition state as long as the final functions cooperate to not
do the sort step more than once. To avoid running the tuplesort object
in randomAccess mode unnecessarily, add a bit of infrastructure to
nodeAgg.c to let the aggregate functions find out whether the transition
state is actually being shared or not.
This doesn't work for the hypothetical aggregates, since those inject
a hypothetical row that isn't traceable to the shared input state.
So they remain marked aggfinalmodify = 'w'.
Tom Lane [Mon, 16 Oct 2017 19:24:36 +0000 (15:24 -0400)]
Repair breakage of aggregate FILTER option.
An aggregate's input expression(s) are not supposed to be evaluated
at all for a row where its FILTER test fails ... but commit 8ed3f11bb
overlooked that requirement. Reshuffle so that aggregates having a
filter clause evaluate their arguments separately from those without.
This still gets the benefit of doing only one ExecProject in the
common case of multiple Aggrefs, none of which have filters.
While at it, arrange for filter clauses to be included in the common
ExecProject evaluation, thus perhaps buying a little bit even when
there are filters.
Tom Lane [Sun, 15 Oct 2017 23:19:18 +0000 (19:19 -0400)]
Restore nodeAgg.c's ability to check for improperly-nested aggregates.
While poking around in the aggregate logic, I noticed that commit 8ed3f11bb broke the logic in nodeAgg.c that purports to detect nested
aggregates, by moving initialization of regular aggregate argument
expressions out of the code segment that checks for that.
You could argue that this check is unnecessary, but it's not much code
so I'm inclined to keep it as a backstop against parser and planner
bugs. However, there's certainly zero value in checking only some of
the subexpressions.
We can make the check complete again, and as a bonus make it a good
deal more bulletproof against future mistakes of the same ilk, by
moving it out to the outermost level of ExecInitAgg. This means we
need to check only once per Agg node not once per aggregate, which
also seems like a good thing --- if the check does find something
wrong, it's not urgent that we report it before the plan node
initialization finishes.
Since this requires remembering the original length of the aggs list,
I deleted a long-obsolete stanza that changed numaggs from 0 to 1.
That's so old it predates our decision that palloc(0) is a valid
operation, in (digs...) 2004, see commit 24a1e20f1.
Tom Lane [Sat, 14 Oct 2017 19:21:39 +0000 (15:21 -0400)]
Explicitly track whether aggregate final functions modify transition state.
Up to now, there's been hard-wired assumptions that normal aggregates'
final functions never modify their transition states, while ordered-set
aggregates' final functions always do. This has always been a bit
limiting, and in particular it's getting in the way of improving the
built-in ordered-set aggregates to allow merging of transition states.
Therefore, let's introduce catalog and CREATE AGGREGATE infrastructure
that lets the finalfn's behavior be declared explicitly.
There are now three possibilities for the finalfn behavior: it's purely
read-only, it trashes the transition state irrecoverably, or it changes
the state in such a way that no more transfn calls are possible but the
state can still be passed to other, compatible finalfns. There are no
examples of this third case today, but we'll shortly make the built-in
OSAs act like that.
This change allows user-defined aggregates to explicitly disclaim support
for use as window functions, and/or to prevent transition state merging,
if their implementations cannot handle that. While it was previously
possible to handle the window case with a run-time error check, there was
not any way to prevent transition state merging, which in retrospect is
something commit 804163bc2 should have provided for. But better late
than never.
In passing, split out pg_aggregate.c's extern function declarations into
a new header file pg_aggregate_fn.h, similarly to what we've done for
some other catalog headers, so that pg_aggregate.h itself can be safe
for frontend files to include. This lets pg_dump use the symbolic
names for relevant constants.
Peter Eisentraut [Sat, 14 Oct 2017 15:40:54 +0000 (11:40 -0400)]
Reinstate genhtml --prefix option for non-vpath builds
In c3d9a66024a93e6d0380bdd1b18cb03a67216b72, the genhtml --prefix option
was removed to get slightly better behavior for vpath builds. genhtml
would then automatically pick a suitable prefix. However, for non-vpath
builds, this makes the coverage output dependent on the length of the
path where the source code happens to be, leading to confusingly
arbitrary results. So put the --prefix option back for non-vpath
builds.
Joe Conway [Fri, 13 Oct 2017 23:06:41 +0000 (16:06 -0700)]
Add missing options to pg_regress help() output
A few command line options accepted by pg_regress were not being output
by help(), including --help itself. Add that one, as well as --version
and --bindir, and the corresponding short options for the first two.
We could consider this for backpatching, but it did not seem worthwhile
and no one else advocated for it, so apply only to master for now.
Author: Joe Conway Reviewed-By: Tom Lane
Discussion: https://postgr.es/m/dd519469-06d7-2662-83ef-c926f6c4f0f1%40joeconway.com
Andres Freund [Fri, 13 Oct 2017 20:16:50 +0000 (13:16 -0700)]
Improve sys/catcache performance.
The following are the individual improvements:
1) Avoidance of FunctionCallInfo based function calls, replaced by
more efficient functions with a native C argument interface.
2) Don't extract columns from a cache entry's tuple whenever matching
entries - instead store them as a Datum array. This also allows to
get rid of having to build dummy tuples for negative & list
entries, and of a hack for dealing with cstring vs. text weirdness.
3) Reorder members of catcache.h struct, so imortant entries are more
likely to be on one cacheline.
4) Allowing the compiler to specialize critical SearchCatCache for a
specific number of attributes allows to unroll loops and avoid
other nkeys dependant initialization.
5) Only initializing the ScanKey when necessary, i.e. catcache misses,
greatly reduces cache unnecessary cpu cache misses.
6) Split of the cache-miss case from the hash lookup, reducing stack
allocations etc in the common case.
7) CatCTup and their corresponding heaptuple are allocated in one
piece.
This results in making cache lookups themselves roughly three times as
fast - full-system benchmarks obviously improve less than that.
I've also evaluated further techniques:
- replace open coded hash with simplehash - the list walk right now
shows up in profiles. Unfortunately it's not easy to do so safely as
an entry's memory location can change at various times, which
doesn't work well with the refcounting and cache invalidation.
- Cacheline-aligning CatCTup entries - helps some with performance,
but the win isn't big and the code for it is ugly, because the
tuples have to be freed as well.
- add more proper functions, rather than macros for
SearchSysCacheCopyN etc., but right now they don't show up in
profiles.
The reason the macro wrapper for syscache.c/h have to be changed,
rather than just catcache, is that doing otherwise would require
exposing the SysCache array to the outside. That might be a good idea
anyway, but it's for another day.
Author: Andres Freund Reviewed-By: Robert Haas
Discussion: https://postgr.es/m/20170914061207.zxotvyopetm7lrrp@alap3.anarazel.de
Andres Freund [Fri, 13 Oct 2017 18:44:51 +0000 (11:44 -0700)]
Add pg_noinline macro to c.h.
Forcing a function not to be inlined can be useful if it's the
slow-path of a performance critical function, or should be visible in
profiles to allow for proper cost attribution.
Author: Andres Freund
Discussion: https://postgr.es/m/20170914061207.zxotvyopetm7lrrp@alap3.anarazel.de
Andres Freund [Fri, 13 Oct 2017 18:54:59 +0000 (11:54 -0700)]
Force "restrict" not to be used when compiling with xlc.
Per buildfarm animal Hornet and followup manual testing by Noah Misch,
it appears xlc miscompiles code using "restrict" in at least some
cases. Allow disabling restrict usage with FORCE_DISABLE_RESTRICT=yes
in template files, and do so for aix/xlc.
Author: Andres Freund and Tom Lane
Discussion: https://postgr.es/m/1820.1507918762@sss.pgh.pa.us
Robert Haas [Fri, 13 Oct 2017 18:53:28 +0000 (14:53 -0400)]
Fix possible crash with Parallel Bitmap Heap Scan.
If a Parallel Bitmap Heap scan's chain of leftmost descendents
includes a BitmapOr whose first child is a BitmapAnd, the prior coding
would mistakenly create a non-shared TIDBitmap and then try to perform
shared iteration.
Tom Lane [Fri, 13 Oct 2017 17:43:55 +0000 (13:43 -0400)]
Improve implementation of CRE-stack-flattening in map_variable_attnos().
I (tgl) objected to the obscure implementation introduced in commit 1c497fa72. This one seems a bit less action-at-a-distance-y, at the
price of repeating a few lines of code.
Improve the comments about what the function is doing, too.
Tom Lane [Fri, 13 Oct 2017 15:46:05 +0000 (11:46 -0400)]
Rely on sizeof(typename) rather than sizeof(variable) in pqformat.h.
In each of the pq_writeintN functions, the three uses of sizeof() should
surely all be consistent. I started out to make them all sizeof(ni),
but on reflection let's make them sizeof(typename) instead. That's more
like our usual style elsewhere, and it's just barely possible that the
failures buildfarm member hornet has shown since 4c119fbcd went in are
caused by the compiler getting confused about sizeof() a parameter that
it's optimizing away.
Peter Eisentraut [Fri, 13 Oct 2017 02:33:34 +0000 (22:33 -0400)]
Log diagnostic messages if errors occur during LDAP auth.
Diagnostic messages seem likely to help users diagnose root
causes more easily, so let's report them as errdetail.
Author: Thomas Munro Reviewed-By: Ashutosh Bapat, Christoph Berg, Alvaro Herrera, Peter Eisentraut
Discussion: https://postgr.es/m/CAEepm=2_dA-SYpFdmNVwvKsEBXOUj=K4ooKovHmvj6jnMdt8dw@mail.gmail.com
Peter Eisentraut [Fri, 13 Oct 2017 02:33:15 +0000 (22:33 -0400)]
Improve LDAP cleanup code in error paths.
After calling ldap_unbind_s() we probably shouldn't try to use the LDAP
connection again to call ldap_get_option(), even if it failed. The OpenLDAP
man page for ldap_unbind[_s] says "Once it is called, the connection to the
LDAP server is closed, and the ld structure is invalid." Otherwise, as a
general rule we should probably call ldap_unbind() before returning in all
paths to avoid leaking resources. It is unlikely there is any practical
leak problem since failure to authenticate currently results in the backend
exiting soon afterwards.
Author: Thomas Munro Reviewed-By: Alvaro Herrera, Peter Eisentraut
Discussion: https://postgr.es/m/20170914141205.eup4kxzlkagtmfac%40alvherre.pgsql
Andres Freund [Thu, 12 Oct 2017 22:25:38 +0000 (15:25 -0700)]
Use C99 restrict via pg_restrict, rather than restrict directly.
Unfortunately using 'restrict' plainly causes problems with MSVC,
which supports restrict only as '__restrict'. Defining 'restrict' to
'__restrict' unfortunately causes a conflict with MSVC's usage of
__declspec(restrict) in headers.
Therefore define pg_restrict to the appropriate keyword instead, and
replace existing usages.
This replaces the temporary workaround introduced in 36b4b91ba078.
Author: Andres Freund
Discussion: https://postgr.es/m/2656.1507830907@sss.pgh.pa.us
Robert Haas [Thu, 12 Oct 2017 21:10:48 +0000 (17:10 -0400)]
Avoid coercing a whole-row variable that is already coerced.
Marginal efficiency and beautification hack. I'm not sure whether
this case ever arises currently, but the pending patch for update
tuple routing will cause it to arise.
Robert Haas [Thu, 12 Oct 2017 20:50:53 +0000 (16:50 -0400)]
Use ResultRelInfo ** rather than ResultRelInfo * for tuple routing.
The previous convention doesn't lend itself to creating ResultRelInfos
lazily, as we already do in ExecGetTriggerResultRel. This patch
doesn't make anything lazier than before, but the pending patch for
UPDATE tuple routing proposes to do so (and there might be other
opportunities as well).
Tom Lane [Thu, 12 Oct 2017 19:20:04 +0000 (15:20 -0400)]
Fix AggGetAggref() so it won't lie to aggregate final functions.
If we merge the transition calculations for two different aggregates,
it's reasonable to assume that the transition function should not care
which of those Aggref structs it gets from AggGetAggref(). It is not
reasonable to make the same assumption about an aggregate final function,
however. Commit 804163bc2 broke this, as it will pass whichever Aggref
was first associated with the transition state in both cases.
This doesn't create an observable bug so far as the core system is
concerned, because the only existing uses of AggGetAggref() are in
ordered-set aggregates that happen to not pay attention to anything
but the input properties of the Aggref; and besides that, we disabled
sharing of transition calculations for OSAs yesterday. Nonetheless,
if some third-party code were using AggGetAggref() in a normal aggregate,
they would be entitled to call this a bug. Hence, back-patch the fix
to 9.6 where the problem was introduced.
In passing, improve some of the comments about transition state sharing.
Tom Lane [Thu, 12 Oct 2017 02:18:01 +0000 (22:18 -0400)]
Prevent sharing transition states between ordered-set aggregates.
This ought to work, but the built-in OSAs are not capable of coping,
because their final-functions destructively modify their transition
state (specifically, the contained tuplesort object). That was fine
when those functions were written, but commit 804163bc2 moved the
goalposts without telling orderedsetaggs.c.
We should fix the built-in OSAs to support this, but it will take
a little work, especially if we don't want to sacrifice performance
in the normal non-shared-state case. Given that it took a year after
9.6 release for anyone to notice this bug, we should not prioritize
sharable-state over nonsharable-state performance. And a proper fix
is likely to be more complicated than we'd want to back-patch, too.
Therefore, let's just put in this stop-gap patch to prevent nodeAgg.c
from choosing to use shared state for OSAs. We can revert it in HEAD
when we get a better fix.
Report from Lukas Eder, diagnosis by me, patch by David Rowley.
Back-patch to 9.6 where the problem was introduced.
Andres Freund [Thu, 12 Oct 2017 02:06:29 +0000 (19:06 -0700)]
Temporary attempt at a workaround for further MSVC restrict build failures.
It appears some versions of msvc use __declspec(restrict) in stdlib.h
and subsidiary headers. Including those after defining 'restrict' to
'__restrict' doesn't work. Try to get the buildfarm green to see
whether there's further problems, by including stdlib.h just before
said define.
Andres Freund [Wed, 11 Oct 2017 23:49:31 +0000 (16:49 -0700)]
Improve performance of SendRowDescriptionMessage.
There's three categories of changes leading to better performance:
- Splitting the per-attribute part of SendRowDescriptionMessage into a
v2 and a v3 version allows avoiding branches for every attribute.
- Preallocating the size of the buffer to be big enough for all
attributes and then using pq_write* avoids unnecessary buffer
size checks & resizing.
- Reusing a persistently allocated StringInfo for all
SendRowDescriptionMessage() invocations avoids repeated allocations
& reallocations.
Author: Andres Freund
Discussion: https://postgr.es/m/20170914063418.sckdzgjfrsbekae4@alap3.anarazel.de
Robert Haas [Wed, 11 Oct 2017 23:52:46 +0000 (19:52 -0400)]
pg_stat_statements: Widen query IDs from 32 bits to 64 bits.
This takes advantage of the infrastructure introduced by commit 81c5e46c490e2426db243eada186995da5bb0ba7 to greatly reduce the
likelihood that two different queries will end up with the same query
ID. It's still possible, of course, but whereas before it the chances
of a collision reached 25% around 50,000 queries, it will now take
more than 3 billion queries.
Backward incompatibility: Because the type exposed at the SQL level is
int8, users may now see negative query IDs in the pg_stat_statements
view (and also, query IDs more than 4 billion, which was the old
limit).
Patch by me, reviewed by Michael Paquier and Peter Geoghegan.
Andres Freund [Wed, 11 Oct 2017 23:26:35 +0000 (16:26 -0700)]
Use one stringbuffer for all rows printed in printtup.c.
This avoids newly allocating, and then possibly growing, the
stringbuffer for every row. For wide rows this can substantially
reduce memory allocator overhead, at the price of not immediately
reducing memory usage after outputting an especially wide row.
Author: Andres Freund
Discussion: https://postgr.es/m/20170914063418.sckdzgjfrsbekae4@alap3.anarazel.de
Andres Freund [Wed, 11 Oct 2017 23:01:52 +0000 (16:01 -0700)]
Add more efficient functions to pqformat API.
There's three prongs to achieve greater efficiency here:
1) Allow reusing a stringbuffer across pq_beginmessage/endmessage,
with the new pq_beginmessage_reuse/endmessage_reuse. This can be
beneficial both because it avoids allocating the initial buffer,
and because it's more likely to already have an correctly sized
buffer.
2) Replacing pq_sendint() with pq_sendint$width() inline
functions. Previously unnecessary and unpredictable branches in
pq_sendint() were needed. Additionally the replacement functions
are implemented more efficiently. pq_sendint is now deprecated, a
separate commit will convert all in-tree callers.
3) Add pq_writeint$width(), pq_writestring(). These rely on sufficient
space in the StringInfo's buffer, avoiding individual space checks
& potential individual resizing. To allow this to be used for
strings, expose mbutil.c's MAX_CONVERSION_GROWTH.
Followup commits will make use of these facilities.
Author: Andres Freund
Discussion: https://postgr.es/m/20170914063418.sckdzgjfrsbekae4@alap3.anarazel.de
Andres Freund [Wed, 11 Oct 2017 23:01:52 +0000 (16:01 -0700)]
Allow to avoid NUL-byte management for stringinfos and use in format.c.
In a lot of the places having appendBinaryStringInfo() maintain a
trailing NUL byte wasn't actually meaningful, e.g. when appending an
integer which can contain 0 in one of its bytes.
Removing this yields some small speedup, but more importantly will be
more consistent when providing faster variants of pq_sendint etc.
Author: Andres Freund
Discussion: https://postgr.es/m/20170914063418.sckdzgjfrsbekae4@alap3.anarazel.de
Andres Freund [Wed, 11 Oct 2017 23:01:52 +0000 (16:01 -0700)]
Add configure infrastructure to detect support for C99's restrict.
Will be used in later commits improving performance for a few key
routines where information about aliasing allows for significantly
better code generation.
This allows to use the C99 'restrict' keyword without breaking C89, or
for that matter C++, compilers. If not supported it's defined to be
empty.
Author: Andres Freund
Discussion: https://postgr.es/m/20170914063418.sckdzgjfrsbekae4@alap3.anarazel.de
Tom Lane [Wed, 11 Oct 2017 21:43:50 +0000 (17:43 -0400)]
Remove unnecessary PG_TRY overhead for CurrentResourceOwner changes.
resowner/README contained advice to use a PG_TRY block to restore the
old CurrentResourceOwner value anywhere that that variable is transiently
changed. That advice was only inconsistently followed, however, and
on reflection it seems like unnecessary overhead. We don't bother
with such a convention for transient CurrentMemoryContext changes,
on the grounds that any (sub)transaction abort will start out by
resetting CurrentMemoryContext to what it wants. But the same is
true of CurrentResourceOwner, so there seems no need to treat it
differently.
Hence, remove PG_TRY blocks that exist only to restore CurrentResourceOwner
before re-throwing the error. There are a couple of places that restore
it along with some other actions, and I left those alone; the restore is
probably unnecessary but no noticeable gain will result from removing it.
Andres Freund [Wed, 11 Oct 2017 19:03:26 +0000 (12:03 -0700)]
Prevent idle in transaction session timeout from sometimes being ignored.
The previous coding in ProcessInterrupts() could lead to
idle_in_transaction_session_timeout being ignored, when
statement_timeout occurred earlier.
The problem was that ProcessInterrupts() would return before
processing the transaction timeout if QueryCancelPending was set while
QueryCancelHoldoffCount != 0 - which is the case when reading new
commands from the client. Ergo when the idle transaction timeout would
hit.
Fix that by removing the early return. Alternatively the transaction
timeout code could have been moved up, but that early return seems
like an issue that could hit other cases too.
Author: Lukas Fittl
Bug: #14821
Discussion:
https://www.postgresql.org/message-id/20170921010956.17345.61461%40wrigleys.postgresql.org
https://www.postgresql.org/message-id/CAP53PkxQnv3OWJpyNPGJYT62uY=n1=2CF_Lpc6gVOFnc0-gazw@mail.gmail.com
Backpatch: 9.6-, where idle_in_transaction_session_timeout was introduced.
Tom Lane [Wed, 11 Oct 2017 20:56:23 +0000 (16:56 -0400)]
Doc: fix missing explanation of default object privileges.
The GRANT reference page, which lists the default privileges for new
objects, failed to mention that USAGE is granted by default for data
types and domains. As a lesser sin, it also did not specify anything
about the initial privileges for sequences, FDWs, foreign servers,
or large objects. Fix that, and add a comment to acldefault() in the
probably vain hope of getting people to maintain this list in future.
Noted by Laurenz Albe, though I editorialized on the wording a bit.
Back-patch to all supported branches, since they all have this behavior.
Tom Lane [Wed, 11 Oct 2017 18:28:33 +0000 (14:28 -0400)]
Fix low-probability loss of NOTIFY messages due to XID wraparound.
Up to now async.c has used TransactionIdIsInProgress() to detect whether
a notify message's source transaction is still running. However, that
function has a quick-exit path that reports that XIDs before RecentXmin
are no longer running. If a listening backend is doing nothing but
listening, and not running any queries, there is nothing that will advance
its value of RecentXmin. Once 2 billion transactions elapse, the
RecentXmin check causes active transactions to be reported as not running.
If they aren't committed yet according to CLOG, async.c decides they
aborted and discards their messages. The timing for that is a bit tight
but it can happen when multiple backends are sending notifies concurrently.
The net symptom therefore is that a sufficiently-long-surviving
listen-only backend starts to miss some fraction of NOTIFY traffic,
but only under heavy load.
The only function that updates RecentXmin is GetSnapshotData().
A brute-force fix would therefore be to take a snapshot before
processing incoming notify messages. But that would add cycles,
as well as contention for the ProcArrayLock. We can be smarter:
having taken the snapshot, let's use that to check for running
XIDs, and not call TransactionIdIsInProgress() at all. In this
way we reduce the number of ProcArrayLock acquisitions from one
per message to one per notify interrupt; that's the same under
light load but should be a benefit under heavy load. Light testing
says that this change is a wash performance-wise for normal loads.
I looked around for other callers of TransactionIdIsInProgress()
that might be at similar risk, and didn't find any; all of them
are inside transactions that presumably have already taken a
snapshot.
Problem report and diagnosis by Marko Tiikkaja, patch by me.
Back-patch to all supported branches, since it's been like this
since 9.0.
Andres Freund [Tue, 10 Oct 2017 21:42:16 +0000 (14:42 -0700)]
Rewrite strnlen replacement implementation from 8a241792f96.
The previous placement of the fallback implementation in libpgcommon
was problematic, because libpqport functions need strnlen
functionality.
Move replacement into libpgport. Provide strnlen() under its posix
name, instead of pg_strnlen(). Fix stupid configure bug, executing the
test only when compiled with threading support.
Author: Andres Freund
Discussion: https://postgr.es/m/E1e1gR2-0005fB-SI@gemulon.postgresql.org
Tom Lane [Tue, 10 Oct 2017 16:51:09 +0000 (12:51 -0400)]
Add missing clean step to src/test/modules/brin/Makefile.
I noticed the tmp_check subdirectory wasn't getting cleaned up
after a check-world run. Apparently pgxs.mk will only do this
for you if you've defined REGRESS. The only other src/test/modules
Makefile that does not set that is snapshot_too_old, and it
does it like this.
Andres Freund [Sun, 8 Oct 2017 22:08:25 +0000 (15:08 -0700)]
Reduce memory usage of targetlist SRFs.
Previously nodeProjectSet only released memory once per input tuple,
rather than once per returned tuple. If the computation of an
individual returned tuple requires a lot of memory, that can lead to
problems.
Instead change things so that the expression context can be reset once
per output tuple, which requires a new memory context to store SRF
arguments in.
This is a longstanding issue, but was hard to fix before 9.6, due to
the way tSRFs where evaluated. But it's fairly easy to fix now. We
could backpatch this into 10, but given there've been fewc omplaints
that doesn't seem worth the risk so far.
Reported-By: Lucas Fairchild
Author: Andres Freund, per discussion with Tom Lane
Discussion: https://postgr.es/m/4514.1507318623@sss.pgh.pa.us
Tom Lane [Sun, 8 Oct 2017 19:25:26 +0000 (15:25 -0400)]
Increase distance between flush requests during bulk file copies.
copy_file() reads and writes data 64KB at a time (with default BLCKSZ),
and historically has issued a pg_flush_data request after each write.
This turns out to interact really badly with macOS's new APFS file
system: a large file copy takes over 100X longer than it ought to on
APFS, as reported by Brent Dearth. While that's arguably a macOS bug,
it's not clear whether Apple will do anything about it in the near
future, and in any case experimentation suggests that issuing flushes
a bit less often can be helpful on other platforms too.
Hence, rearrange the logic in copy_file() so that flush requests are
issued once per N writes rather than every time through the loop.
I set the FLUSH_DISTANCE to 32MB on macOS (any less than that still
results in a noticeable speed degradation on APFS), but 1MB elsewhere.
In limited testing on Linux and FreeBSD, this seems slightly faster
than the previous code, and certainly no worse. It helps noticeably
on macOS even with the older HFS filesystem.
A simpler change would have been to just increase the size of the
copy buffer without changing the loop logic, but that seems likely
to trash the processor cache without really helping much.
Back-patch to 9.6 where we introduced msync() as an implementation
option for pg_flush_data(). The problem seems specific to APFS's
mmap/msync support, so I don't think we need to go further back.
Tom Lane [Sun, 8 Oct 2017 16:23:32 +0000 (12:23 -0400)]
Reduce "X = X" to "X IS NOT NULL", if it's easy to do so.
If the operator is a strict btree equality operator, and X isn't volatile,
then the clause must yield true for any non-null value of X, or null if X
is null. At top level of a WHERE clause, we can ignore the distinction
between false and null results, so it's valid to simplify the clause to
"X IS NOT NULL". This is a useful improvement mainly because we'll get
a far better selectivity estimate in most cases.
Because such cases seldom arise in well-written queries, it is unappetizing
to expend a lot of planner cycles looking for them ... but it turns out
that there's a place we can shoehorn this in practically for free, because
equivclass.c already has to detect and reject candidate equivalences of the
form X = X. That doesn't catch every place that it would be valid to
simplify to X IS NOT NULL, but it catches the typical case. Working harder
doesn't seem justified.
Tom Lane [Sat, 7 Oct 2017 22:04:25 +0000 (18:04 -0400)]
Improve pg_regress's error reporting for schedule-file problems.
The previous coding here trashed the line buffer as it scanned it,
making it impossible to print the source line in subsequent error
messages. With a few save/restore/strdup pushups we can improve
that situation.
In passing, move the free'ing of the various strings that are collected
while processing one set of tests down to the bottom of the loop.
That's simpler, less surprising, and should make valgrind less unhappy
about the strings that were previously leaked by the last iteration.
Tom Lane [Sat, 7 Oct 2017 21:20:09 +0000 (17:20 -0400)]
Enforce our convention about max number of parallel regression tests.
We have a very old rule that parallel_schedule should have no more
than twenty tests in any one parallel group, so as to provide a
bound on the number of concurrently running processes needed to
pass the tests. But people keep forgetting the rule, so let's add
a few lines of code to check it.
Tom Lane [Sat, 7 Oct 2017 17:19:13 +0000 (13:19 -0400)]
Clean up sloppy maintenance of regression test schedule files.
The partition_join test was added to a parallel group that was already
at the maximum of 20 concurrent tests. The hash_func test wasn't
added to serial_schedule at all. The identity and partition_join tests
were added to serial_schedule with the aid of a dartboard, rather than
maintaining consistency with parallel_schedule.
There are proposals afoot to make these sorts of errors harder to make,
but in the meantime let's fix the ones already in place.
Tom Lane [Fri, 6 Oct 2017 23:18:58 +0000 (19:18 -0400)]
Fix crash when logical decoding is invoked from a PL function.
The logical decoding functions do BeginInternalSubTransaction and
RollbackAndReleaseCurrentSubTransaction to clean up after themselves.
It turns out that AtEOSubXact_SPI has an unrecognized assumption that
we always need to cancel the active SPI operation in the SPI context
that surrounds the subtransaction (if there is one). That's true
when the RollbackAndReleaseCurrentSubTransaction call is coming from
the SPI-using function itself, but not when it's happening inside
some unrelated function invoked by a SPI query. In practice the
affected callers are the various PLs.
To fix, record the current subtransaction ID when we begin a SPI
operation, and clean up only if that ID is the subtransaction being
canceled.
Also, remove AtEOSubXact_SPI's assertion that it must have cleaned
up the surrounding SPI context's active tuptable. That's proven
wrong by the same test case.
Also clarify (or, if you prefer, reinterpret) the calling conventions
for _SPI_begin_call and _SPI_end_call. The memory context cleanup
in the latter means that these have always had the flavor of a matched
resource-management pair, but they weren't documented that way before.
Per report from Ben Chobot.
Back-patch to 9.4 where logical decoding came in. In principle,
the SPI changes should go all the way back, since the problem dates
back to commit 7ec1c5a86. But given the lack of field complaints
it seems few people are using internal subtransactions in this way.
So I don't feel a need to take any risks in 9.2/9.3.
Tom Lane [Fri, 6 Oct 2017 18:28:42 +0000 (14:28 -0400)]
Fix intra-query memory leakage in nodeProjectSet.c.
Both ExecMakeFunctionResultSet() and evaluation of simple expressions
need to be done in the per-tuple memory context, not per-query, else
we leak data until end of query. This is a consideration that was
missed while refactoring code in the ProjectSet patch (note that in
pre-v10, ExecMakeFunctionResult is called in the per-tuple context).
Per bug #14843 from Ben M. Diagnosed independently by Andres and myself.
Tom Lane [Fri, 6 Oct 2017 16:20:12 +0000 (12:20 -0400)]
Fix access-off-end-of-array in clog.c.
Sloppy loop coding in set_status_by_pages() resulted in fetching one array
element more than it should from the subxids[] array. The odds of this
resulting in SIGSEGV are pretty small, but we've certainly seen that happen
with similar mistakes elsewhere. While at it, we can get rid of an extra
TransactionIdToPage() calculation per loop.
Per report from David Binderman. Back-patch to all supported branches,
since this code is quite old.
Tom Lane [Fri, 6 Oct 2017 15:35:49 +0000 (11:35 -0400)]
#ifdef out some dead code in psql/mainloop.c.
This pg_send_history() call is unreachable, since the block it's in
is currently only entered in !cur_cmd_interactive mode. But rather
than just delete it, make it #ifdef NOT_USED, in hopes that we'll
remember to enable it if we ever change that decision.
Per report from David Binderman. Since this is basically cosmetic,
I see no great need to back-patch.
Alvaro Herrera [Fri, 6 Oct 2017 15:14:42 +0000 (17:14 +0200)]
Fix traversal of half-frozen update chains
When some tuple versions in an update chain are frozen due to them being
older than freeze_min_age, the xmax/xmin trail can become broken. This
breaks HOT (and probably other things). A subsequent VACUUM can break
things in more serious ways, such as leaving orphan heap-only tuples
whose root HOT redirect items were removed. This can be seen because
index creation (or REINDEX) complain like
ERROR: XX000: failed to find parent tuple for heap-only tuple at (0,7) in table "t"
Because of relfrozenxid contraints, we cannot avoid the freezing of the
early tuples, so we must cope with the results: whenever we see an Xmin
of FrozenTransactionId, consider it a match for whatever the previous
Xmax value was.
This problem seems to have appeared in 9.3 with multixact changes,
though strictly speaking it seems unrelated.
Since 9.4 we have commit 37484ad2a "Change the way we mark tuples as
frozen", so the fix is simple: just compare the raw Xmin (still stored
in the tuple header, since freezing merely set an infomask bit) to the
Xmax. But in 9.3 we rewrite the Xmin value to FrozenTransactionId, so
the original value is lost and we have nothing to compare the Xmax with.
To cope with that case we need to compare the Xmin with FrozenXid,
assume it's a match, and hope for the best. Sadly, since you can
pg_upgrade a 9.3 instance containing half-frozen pages to newer
releases, we need to keep the old check in newer versions too, which
seems a bit brittle; I hope we can somehow get rid of that.
I didn't optimize the new function for performance. The new coding is
probably a bit slower than before, since there is a function call rather
than a straight comparison, but I'd rather have it work correctly than
be fast but wrong.
This is a followup after 20b655224249 fixed a few related problems.
Apparently, in 9.6 and up there are more ways to get into trouble, but
in 9.3 - 9.5 I cannot reproduce a problem anymore with this patch, so
there must be a separate bug.
Reported-by: Peter Geoghegan Diagnosed-by: Peter Geoghegan, Michael Paquier, Daniel Wood,
Yi Wen Wong, Álvaro
Discussion: https://postgr.es/m/CAH2-Wznm4rCrhFAiwKPWTpEw2bXDtgROZK7jWWGucXeH3D1fmA@mail.gmail.com
Robert Haas [Fri, 6 Oct 2017 15:11:10 +0000 (11:11 -0400)]
Basic partition-wise join functionality.
Instead of joining two partitioned tables in their entirety we can, if
it is an equi-join on the partition keys, join the matching partitions
individually. This involves teaching the planner about "other join"
rels, which are related to regular join rels in the same way that
other member rels are related to baserels. This can use significantly
more CPU time and memory than regular join planning, because there may
now be a set of "other" rels not only for every base relation but also
for every join relation. In most practical cases, this probably
shouldn't be a problem, because (1) it's probably unusual to join many
tables each with many partitions using the partition keys for all
joins and (2) if you do that scenario then you probably have a big
enough machine to handle the increased memory cost of planning and (3)
the resulting plan is highly likely to be better, so what you spend in
planning you'll make up on the execution side. All the same, for now,
turn this feature off by default.
Currently, we can only perform joins between two tables whose
partitioning schemes are absolutely identical. It would be nice to
cope with other scenarios, such as extra partitions on one side or the
other with no match on the other side, but that will have to wait for
a future patch.
Ashutosh Bapat, reviewed and tested by Rajkumar Raghuwanshi, Amit
Langote, Rafia Sabih, Thomas Munro, Dilip Kumar, Antonin Houska, Amit
Khandekar, and by me. A few final adjustments by me.
Robert Haas [Thu, 5 Oct 2017 17:06:46 +0000 (13:06 -0400)]
On attach, consider skipping validation of subpartitions individually.
If the table attached as a partition is itself partitioned, individual
partitions might have constraints strong enough to skip scanning the
table even if the table actually attached does not. This is pretty
cheap to check, and possibly a big win if it works out.
Robert Haas [Thu, 5 Oct 2017 15:34:38 +0000 (11:34 -0400)]
Allow DML commands that create tables to use parallel query.
Haribabu Kommi, reviewed by Dilip Kumar and Rafia Sabih. Various
cosmetic changes by me to explain why this appears to be safe but
allowing inserts in parallel mode in general wouldn't be. Also, I
removed the REFRESH MATERIALIZED VIEW case from Haribabu's patch,
since I'm not convinced that case is OK, and hacked on the
documentation somewhat.
Tom Lane [Thu, 5 Oct 2017 14:47:47 +0000 (10:47 -0400)]
Improve comments in vacuum_rel() and analyze_rel().
Remove obsolete references to get_rel_oids(). Avoid listing specific
relkinds in the comments, since we seem unable to keep such things
in sync with the code, and it's not all that helpful anyhow.
Noted by Michael Paquier, though I rewrote the comments a bit more.
Peter Eisentraut [Thu, 31 Aug 2017 02:16:50 +0000 (22:16 -0400)]
Document and use SPI_result_code_string()
A lot of semi-internal code just prints out numeric SPI error codes,
which is not very helpful. We already have an API function to convert
the codes to a string, so let's make more use of that.
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
Andres Freund [Wed, 4 Oct 2017 07:22:38 +0000 (00:22 -0700)]
Replace binary search in fmgr_isbuiltin with a lookup array.
Turns out we have enough functions that the binary search is quite
noticeable in profiles.
Thus have Gen_fmgrtab.pl build a new mapping from a builtin function's
oid to an index in the existing fmgr_builtins array. That keeps the
additional memory usage at a reasonable amount.
Author: Andres Freund, with input from Tom Lane
Discussion: https://postgr.es/m/20170914065128.a5sk7z4xde5uy3ei@alap3.anarazel.de
Tom Lane [Tue, 3 Oct 2017 22:53:44 +0000 (18:53 -0400)]
Allow multiple tables to be specified in one VACUUM or ANALYZE command.
Not much to say about this; does what it says on the tin.
However, formerly, if there was a column list then the ANALYZE action was
implied; now it must be specified, or you get an error. This is because
it would otherwise be a bit unclear what the user meant if some tables
have column lists and some don't.
Nathan Bossart, reviewed by Michael Paquier and Masahiko Sawada, with some
editorialization by me
Tom Lane [Tue, 3 Oct 2017 18:00:56 +0000 (14:00 -0400)]
Fix race condition with unprotected use of a latch pointer variable.
Commit 597a87ccc introduced a latch pointer variable to replace use
of a long-lived shared latch in the shared WalRcvData structure.
This was not well thought out, because there are now hazards of the
pointer variable changing while it's being inspected by another
process. This could obviously lead to a core dump in code like
if (WalRcv->latch)
SetLatch(WalRcv->latch);
and there's a more remote risk of a torn read, if we have any
platforms where reading/writing a pointer is not atomic.
An actual problem would occur only if the walreceiver process
exits (gracefully) while the startup process is trying to
signal it, but that seems well within the realm of possibility.
To fix, treat the pointer variable (not the referenced latch)
as being protected by the WalRcv->mutex spinlock. There
remains a race condition that we could apply SetLatch to a
process latch that no longer belongs to the walreceiver, but
I believe that's harmless: at worst it'd cause an extra wakeup
of the next process to use that PGPROC structure.
Back-patch to v10 where the faulty code was added.
Alvaro Herrera [Tue, 3 Oct 2017 12:58:25 +0000 (14:58 +0200)]
Fix coding rules violations in walreceiver.c
1. Since commit b1a9bad9e744 we had pstrdup() inside a
spinlock-protected critical section; reported by Andreas Seltenreich.
Turn those into strlcpy() to stack-allocated variables instead.
Backpatch to 9.6.
2. Since commit 9ed551e0a4fd we had a pfree() uselessly inside a
spinlock-protected critical section. Tom Lane noticed in code review.
Move down. Backpatch to 9.6.
3. Since commit 64233902d22b we had GetCurrentTimestamp() (a kernel
call) inside a spinlock-protected critical section. Tom Lane noticed in
code review. Move it up. Backpatch to 9.2.
4. Since commit 1bb2558046cc we did elog(PANIC) while holding spinlock.
Tom Lane noticed in code review. Release spinlock before dying.
Backpatch to 9.2.
Peter Eisentraut [Fri, 22 Sep 2017 17:51:01 +0000 (13:51 -0400)]
Expand collation documentation
Document better how to create custom collations and what locale strings
ICU accepts. Explain the ICU examples in more detail. Also update the
text on the CREATE COLLATION reference page a bit to take ICU more into
account.
Andres Freund [Sun, 1 Oct 2017 22:36:14 +0000 (15:36 -0700)]
Replace most usages of ntoh[ls] and hton[sl] with pg_bswap.h.
All postgres internal usages are replaced, it's just libpq example
usages that haven't been converted. External users of libpq can't
generally rely on including postgres internal headers.
Note that this includes replacing open-coded byte swapping of 64bit
integers (using two 32 bit swaps) with a single 64bit swap.
Where it looked applicable, I have removed netinet/in.h and
arpa/inet.h usage, which previously provided the relevant
functionality. It's perfectly possible that I missed other reasons for
including those, the buildfarm will tell.
Author: Andres Freund
Discussion: https://postgr.es/m/20170927172019.gheidqy6xvlxb325@alap3.anarazel.de
Andres Freund [Sun, 1 Oct 2017 22:17:10 +0000 (15:17 -0700)]
Allow pg_ctl kill to send SIGKILL.
Previously that was disallowed out of an abundance of
caution. Providing KILL support however is helpful to make the
013_crash_restart.pl test portable, and there's no actual issue with
allowing it. SIGABRT, which has similar consequences except it also
dumps core, was already allowed.
Author: Andres Freund
Discussion: https://postgr.es/m/45d42d41-6145-9be1-7261-84acf6d9e344@2ndQuadrant.com
projects / postgresql / log