|From:||David Fetter <david(at)fetter(dot)org>|
|To:||PostgreSQL Announce <pgsql-announce(at)postgresql(dot)org>|
|Subject:||== PostgreSQL Weekly News - November 26 2017 ==|
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== PostgreSQL Weekly News - November 26 2017 ==
== PostgreSQL Product News ==
Pgpool-II 3.7.0 and pgpoolAdmin 3.7.0 released.
repmgr 4.0, a replication manager for PostgreSQL, released.
== PostgreSQL Jobs for November ==
== PostgreSQL Local ==
PGDAY Brasilia 2017 will take place December 2, 2017.
PGConf Local: Austin will be held December 4 - 5, 2017. Program available
and registration is now open at
PGConf.ASIA 2017 will take place on December 4-6 2017 in Akihabara, Tokyo,
FOSDEM PGDay 2018, a one day conference held before the main FOSDEM event will
be held in Brussels, Belgium, on Feb 2nd, 2018.
Prague PostgreSQL Developer Day 2018 (P2D2 2018) is a two-day
conference that will be held on February 14-15 2018 in Prague, Czech Republic.
The CfP is open until January 5, 2018 at https://p2d2.cz/callforpapers
PostgreSQL(at)SCaLE is a two day, two track event which takes place on
March 8-9, 2018, at Pasadena Convention Center, as part of SCaLE 16X.
The CfP is open through October 31, 2017 at
Nordic PGDay 2018 will be held in Oslo, Norway, at the Radisson Blu Hotel
Nydalen, on March 13, 2018. The CfP is open through December 31, 2017 at
pgDay Paris 2018 will be held in Paris, France at the Espace Saint-Martin, on
March 15 2018. The CfP is open until December 31, 2017.
The German-speaking PostgreSQL Conference 2018 will take place on April 13th,
2018 in Berlin. The CfP is open until January 09, 2018 at
http://2018.pgconf.de/de/callforpapers.html and the conference site is at
PGCon 2018 will take place in Ottawa on May 29 - June 2018. The CfP goes out
PGConf.Brazil 2018 will take place in São Paulo, Brazil on August 3-4 2018. The
CfP will open soon.
== PostgreSQL in the News ==
Planet PostgreSQL: http://planet.postgresql.org/
PostgreSQL Weekly News is brought to you this week by David Fetter
Submit news and announcements by Sunday at 3:00pm EST5EDT. Please send English
language ones to david(at)fetter(dot)org, German language to pwn(at)pgug(dot)de, Italian
language to pwn(at)itpug(dot)org(dot)
== Applied Patches ==
Simon Riggs pushed:
- Reduce test variability for toast_tuple_target test.
- Parameter toast_tuple_target controls TOAST for new rows. Specifies the point
at which we try to move long column values into TOAST tables. No effect on
existing rows. Discussion:
Author: Simon Riggs <simon(at)2ndQudrant(dot)com> Reviewed-by: Andrew Dunstan
- Fix pg_control_checkpoint from commit 4b0d28de06. Author: Simon Riggs
<simon(at)2ndQuadrant(dot)com> Reported-By: Andreas Seltenreich <seltenreich(at)gmx(dot)de>
- Set es_output_cid in replication worker. Allows triggers to operate correctly
Author: Petr Jelinek <petr(dot)jelinek(at)2ndquadrant(dot)com> Reported-by: Konstantin
- Show partition info from psql \d+. Author: Amit Langote, Ashutosh Bapat
Reviewed-by: Álvaro Herrera, Simon Riggs
- Sort default partition to bottom of psql \d+. Minor patch to change sort
order only Author: Ashutosh Bapat Reviewed-by: Álvaro Herrera, Simon Riggs
- Tweak code for older compilers. Attempt to quiesce build farm Author: Tomas
- Generational memory allocator. Add new style of memory allocator, known as
Generational appropriate for use in cases where memory is allocated and then
freed in roughly oldest first order (FIFO). Use new allocator for logical
decoding’s reorderbuffer to significantly reduce memory usage and improve
performance. Author: Tomas Vondra Reviewed-by: Simon Riggs
Robert Haas pushed:
- Pass eflags down to parallel workers. Currently, there are no known
consequences of this oversight, so no back-patch. Several of the EXEC_FLAG_*
constants aren't usable in parallel mode anyway, and potential problems
related to the presence or absence of OIDs (see EXEC_FLAG_WITH_OIDS,
EXEC_FLAG_WITHOUT_OIDS) seem at present to be masked by the unconditional
projection step performed by Gather and Gather Merge. In general, however, it
seems important that all participants agree on the values of these flags,
which modify executor behavior globally, and a pending patch to skip
projection in Gather (Merge) would be outright broken in certain cases without
this fix. Patch by me, based on investigation of a test case provided by Amit
Kapila. This patch was also reviewed by Amit Kapila. Discussion:
- Tweak use of ExecContextForcesOids by Gather (Merge). Specifically, pass the
outer plan's PlanState instead of our own PlanState. At present,
ExecContextForcesOids doesn't actually care which PlanState we pass; it just
looks through to the underlying EState to find the result relation or
top-level eflags. However, in the future it might care. If that happens, and
if our goal is to get a tuple descriptor that matches that of the outer plan,
then I think what we care about is whether the outer plan's context forces
OIDs, rather than whether our own context forces OIDs, just as we use the
outer node's target list rather than our own. Patch by me, reviewed by Amit
- Fix multiple problems with satisfies_hash_partition. Fix the function header
comment to describe the actual behavior. Check that table OID, modulus, and
remainder arguments are not NULL before accessing them. Check that the
modulus and remainder are sensible. If the table OID doesn't exist, return
NULL instead of emitting an internal error, similar to what we do elsewhere.
Check that the actual argument types match, or at least are binary coercible
to, the expected argument types. Correctly handle invocation of this function
using the VARIADIC syntax. Add regression tests. Robert Haas and Amul Sul,
per a report by Andreas Seltenreich and subsequent followup investigation.
- Provide for forward compatibility with future minor protocol versions.
Previously, any attempt to request a 3.x protocol version other than 3.0 would
lead to a hard connection failure, which made the minor protocol version
really no different from the major protocol version and precluded gentle
protocol version breaks. Instead, when the client requests a 3.x protocol
version where x is greater than 0, send the new NegotiateProtocolVersion
message to convey that we support only 3.0. This makes it possible to
introduce new minor protocol versions without requiring a connection retry
when the server is older. In addition, if the startup packet includes
name/value pairs where the name starts with "_pq_.", assume that those are
protocol options, not GUCs. Include those we don't support (i.e. all of them,
at present) in the NegotiateProtocolVersion message so that the client knows
they were not understood. This makes it possible for the client to request
previously-unsupported features without bumping the protocol version at all;
the client can tell from the server's response whether the option was
understood. It will take some time before servers that support these new
facilities become common in the wild; to speed things up and make things
easier for a future 3.1 protocol version, back-patch to all supported
releases. Robert Haas and Badrul Chowdhury Discussion:
- Avoid projecting tuples unnecessarily in Gather and Gather Merge. It's most
often the case that the target list for the Gather (Merge) node matches the
target list supplied by the underlying plan node; when this is so, we can
avoid the overhead of projecting. This depends on commit
f455e1125e2588d4cd4fc663c6a10da4e003a3b5 for proper functioning. Idea by
Andres Freund. Patch by me. Review by Amit Kapila. Discussion:
Tom Lane pushed:
- Use out-of-line M68K spinlock code for OpenBSD as well as NetBSD. David
Carlier (from a patch being carried by OpenBSD packagers) Discussion:
- Add support for Motorola 88K to s_lock.h. Apparently there are still people
out there who care about this old architecture. They probably care about
dusty versions of Postgres too, so back-patch to all supported branches.
David Carlier (from a patch being carried by OpenBSD packagers) Discussion:
- Support index-only scans in contrib/cube and contrib/seg GiST indexes. To do
this, we only have to remove the compress and decompress support functions,
which have never done anything more than detoasting. In the wake of commit
d3a4f89d8, this results in automatically enabling index-only scans, since the
core code will now know that the stored representation is the same as the
original data (up to detoasting). The only exciting part of this is that
ALTER OPERATOR FAMILY lacks a way to drop a support function that was declared
as being part of an opclass rather than being loose in the family. For the
moment, we'll hack our way to a solution with a manual update of the pg_depend
entry type, which is what distinguishes the two cases. Perhaps someday it'll
be worth providing a cleaner way to do that, but for now it seems like a very
niche problem. Note that the underlying C functions remain, to support use of
the shared libraries with older versions of the modules' SQL declarations.
Someday we may be able to remove them, but not soon. Andrey Borodin, reviewed
by me Discussion:
- Doc: fix broken markup.
- pgbench: fix stats reporting when some transactions are skipped. pgbench can
skip some transactions when both -R and -L options are used. Previously, this
resulted in slightly silly statistics both in progress reports and final
output, because the skipped transactions were counted as executed for TPS and
related stats. Discount skipped xacts in TPS numbers, and also when figuring
the percentage of xacts exceeding the latency limit. Also, don't print
per-script skipped-transaction counts when there is only one script. That's
redundant with the overall count, and it's inconsistent with the fact that we
don't print other per-script stats when there's only one script. Clean up
some unnecessary interactions between what should be independent options that
were due to that decision. While at it, avoid division-by-zero in cases where
no transactions were executed. While on modern platforms this would generally
result in printing "NaN" rather than a crash, that isn't spelled consistently
across platforms and it would confuse many people. Skip the relevant output
entirely when practical, else print zeroes. Fabien Coelho, reviewed by Steve
Singer, additional hacking by me Discussion:
- Ensure sizeof(GenerationChunk) is maxaligned. Per buildfarm. Also improve
- Fix unstable regression test added by commits 59b71c6fe et al. The query
didn't really have a preferred index, leading to platform- specific choices of
which one to use. Adjust it to make sure tenk1_hundred is always chosen. Per
- Fix bug in generation.c's valgrind support. This doesn't look like the last
such bug, but it's one that the test_decoding regression test is tripping
over. Per buildfarm. Tomas Vondra Discussion:
- Mostly-cosmetic improvements in memory chunk header alignment coding. Add
commentary about what we're doing and why. Apply the method used for padding
in GenerationChunk to AllocChunkData, replacing the rather ad-hoc solution
used in commit 7e3aa03b4. Reorder fields in GenerationChunk so that the
padding calculation will work even if sizeof(size_t) is different from
sizeof(void *) --- likely that will never happen, but we don't need the
assumption if we do it like this. Improve static assertions about alignment.
In passing, fix a couple of oversights in the "large chunk" path in
- Improve valgrind logic in aset.c, and fix multiple issues in generation.c.
Revise aset.c so that all the "private" fields of chunk headers are marked
NOACCESS when outside the module, improving on the previous coding which
protected only requested_size. Fix a couple of corner case bugs, such as
failing to re-protect the header during a failure exit from AllocSetRealloc,
and wrong padding-size calculation for an oversize allocation request. Apply
the same design to generation.c, and also fix several bugs therein that I
found by dint of hacking the code to use generation.c as the standard
allocator and then running the core regression tests with it. Notably, we
have to track the actual size of each block, else the wipe_mem call in
GenerationReset clears the wrong amount of memory for an oversize-chunk block;
and GenerationCheck needs a way of identifying freed chunks that isn't fooled
by palloc(0). I chose to fix the latter by resetting the context pointer to
NULL in a freed chunk, roughly like what happens in a freed aset.c chunk.
- Improve planner's handling of set-returning functions in grouping columns.
Improve query_is_distinct_for() to accept SRFs in the targetlist when we can
prove distinctness from a DISTINCT clause. In that case the de-duplication
will surely happen after SRF expansion, so the proof still works. Continue to
punt in the case where we'd try to prove distinctness from GROUP BY (or, in
the future, source relations). To do that, we'd have to determine whether the
SRFs were in the grouping columns or elsewhere in the tlist, and it still
doesn't seem worth the trouble. But this trivial change allows us to
recognize that "SELECT DISTINCT unnest(foo) FROM ..." produces unique-ified
output, which seems worth having. Also, fix estimate_num_groups() to consider
the possibility of SRFs in the grouping columns. Its failure to do so was
masked before v10 because grouping_planner() scaled up plan rowcount estimates
by the estimated SRF multiplier after performing grouping. That doesn't
happen anymore, which is more correct, but it means we need an adjustment in
the estimate for the number of groups. Failure to do this leads to an
underestimate for the number of output rows of subqueries like "SELECT
DISTINCT unnest(foo)" compared to what 9.6 and earlier estimated, thus
breaking plan choices in some cases. Per report from Dmitry Shalashov.
Back-patch to v10 to avoid degraded plan choices compared to previous
- Update buffile.h/.c comments for removal of non-temp option. Commit 11e264517
removed BufFile's isTemp flag, thereby eliminating the possibility of
resurrecting BufFileCreate(). But it left that function in place, as well as
a bunch of comments describing how things worked for the non-temp-file case.
At best, that's now a source of confusion. So remove the
long-since-commented-out function and change relevant comments. I (tgl)
wanted to rename BufFileCreateTemp() to BufFileCreate(), but that seems not to
be the consensus position, so leave it as-is. In passing, fix commit
f0828b2fc's failure to update BufFileSeek's comment to match the change of its
argument type from long to off_t. (I think that might actually have been
intentional at the time, but now that 64-bit off_t is nearly universal, it
looks anachronistic.) Thomas Munro and Tom Lane Discussion:
- Repair failure with SubPlans in multi-row VALUES lists. When nodeValuesscan.c
was written, it was impossible to have a SubPlan in VALUES --- any sub-SELECT
there would have to be uncorrelated and thereby would produce an InitPlan
instead. We therefore took a shortcut in the logic that throws away a
ValuesScan's per-row expression evaluation data structures. This was broken
by the introduction of LATERAL however; a sub-SELECT containing a lateral
reference produces a correlated SubPlan. The cleanest fix for this would be
to give up the optimization of discarding the expression eval state. But that
still seems pretty unappetizing for long VALUES lists. It seems to work to
just prevent the subexpressions from hooking into the ValuesScan node's
subPlan list, so let's do that and see how well it works. (If this breaks,
due to additional connections between the subexpressions and the outer query
structures, we might consider compromises like throwing away data only for
VALUES rows not containing SubPlans.) Per bug #14924 from Christian Duta.
Back-patch to 9.3 where LATERAL was introduced. Discussion:
- Avoid formally-undefined use of memcpy() in hstoreUniquePairs().
hstoreUniquePairs() often called memcpy with equal source and destination
pointers. Although this is almost surely harmless in practice, it's undefined
according to the letter of the C standard. Some versions of valgrind will
complain about it, and some versions of libc as well (cf. commit ad520ec4a).
Tweak the code to avoid doing that. Noted by Tomas Vondra. Back-patch to all
supported versions because of the hazard of libc assertions. Discussion:
- Replace raw timezone source data with IANA's new compact format.
Traditionally IANA has distributed their timezone data in pure source form,
replete with extensive historical comments. As of release 2017c, they've
added a compact single-file format that omits comments and abbreviates command
keywords. This form is way shorter than the pure source, even before
considering its allegedly better compressibility. Hence, let's distribute the
data in that form rather than pure source. I'm pushing this now, rather than
at the next timezone database update, so that it's easy to confirm that this
data file produces compiled zic output that's identical to what we were
getting before. Discussion: https://firstname.lastname@example.org
- Update MSVC build process for new timezone data. Missed this dependency in
commits 7cce222c9 et al.
- Pad XLogReaderState's main_data buffer more aggressively. Originally, we
palloc'd this buffer just barely big enough to hold the largest xlog record
seen so far. It turns out that that can result in valgrind complaints,
because some compilers will emit code that assumes it can safely fetch padding
bytes at the end of a struct, and those padding bytes were unallocated so far
as aset.c was concerned. We can fix that by MAXALIGN'ing the palloc request
size, ensuring that it is big enough to include any possible padding that
might've been omitted from the on-disk record. An additional objection to the
original coding is that it could result in many repeated palloc cycles, in the
worst case where we see a series of gradually larger xlog records. We can
ameliorate that cheaply by imposing a minimum buffer size that's large enough
for most xlog records. BLCKSZ/2 was chosen after a bit of discussion. In
passing, remove an obsolete comment in struct xl_heap_new_cid that the
combocid field is free due to alignment considerations. Perhaps that was true
at some point, but it's not now. Back-patch to 9.5 where this code came in.
Magnus Hagander pushed:
- Fix typo. Daniel Gustafsson
Noah Misch pushed:
- Build src/test/isolation during "make" and "make install". This hack closes a
race condition in "make -j check-world" and "make -j installcheck-world".
Back-patch to v10, before which these parallel invocations had worse problems.
- Support linking with MinGW-built Perl. This is necessary for ActivePerl 5.18
onwards and for Strawberry Perl. It is not sufficient for 32-bit builds with
newer Visual Studio; these fail with error LINK2026. Back-patch to 9.3 (all
supported versions). Reported by Victor Wagner. Discussion:
Fujii Masao pushed:
- doc: mention wal_receiver_status_interval as GUC affecting logical rep worker.
wal_receiver_timeout, wal_receiver_status_interval and
wal_retrieve_retry_interval configuration parameters affect the logical rep
worker, but previously only wal_receiver_status_interval was not mentioned as
such parameter in the doc. Back-patch to v10 where logical rep was added.
Author: Masahiko Sawada Discussion:
Peter Eisentraut pushed:
- Convert documentation to DocBook XML. Since some preparation work had already
been done, the only source changes left were changing empty-element tags like
<xref linkend="foo"> to <xref linkend="foo"/>, and changing the DOCTYPE. The
source files are still named *.sgml, but they are actually XML files now.
Renaming could be considered later. In the build system, the intermediate
step to convert from SGML to XML is removed. Everything is build straight
from the source files again. The OpenSP (or the old SP) package is no longer
needed. The documentation toolchain instructions are updated and are much
simpler now. Peter Eisentraut, Alexander Lakhin, Jürgen Purtz
Andres Freund pushed:
- Fix handling of NULLs returned by aggregate combine functions. When strict
aggregate combine functions, used in multi-stage/parallel aggregation,
returned NULL, we didn't check for that, invoking the combine function with
NULL the next round, despite it being strict. The equivalent code invoking
normal transition functions has a check for that situation, which did not get
copied in a7de3dc5c346. Fix the bug by adding the equivalent check. Based on
a quick look I could not find any strict combine functions in core actually
returning NULL, and it doesn't seem very likely external users have done so.
So this isn't likely to have caused issues in practice. Add tests verifying
transition / combine functions returning NULL is tested. Reported-By: Andres
Freund Author: Andres Freund Discussion:
Backpatch: 9.6, where parallel aggregation was introduced
Dean Rasheed pushed:
- Doc: add a summary table to the CREATE POLICY docs. This table summarizes
which RLS policy expressions apply to each command type, and whether they
apply to the old or new tuples (or both), which saves reading through a lot of
text. Rod Taylor, hacked on by me. Reviewed by Fabien Coelho. Discussion:
- Fix broken XML in CREATE POLICY sgml. Commit 87c2a17fee failed to close some
tags (necessary now that the SGML docs are in fact XML).
- RLS comment fixes. The comments in get_policies_for_relation() say that
CREATE POLICY does not support defining restrictive policies. This is no
longer true, starting from PG10.
Joe Conway pushed:
- Make has_sequence_privilege support WITH GRANT OPTION. The various
has_*_privilege() functions all support an optional WITH GRANT OPTION added to
the supported privilege types to test whether the privilege is held with grant
option. That is, all except has_sequence_privilege() variations. Fix that.
Back-patch to all supported branches. Discussion:
== Pending Patches ==
Anthony Bykov sent in another revision of a patch to implement a Jsonb TRANSFORM
Alexander Korotkov sent in another revision of a patch to fix KNN and negative
coordinate handling for contrib/cube.
Brian Cloutier sent in another revision of a patch to add PGDLLIMPORT lines to
Martín Marqués sent in a patch to quiet MSVC's warnings about isatty().
Masahiko Sawada sent in three more revisions of a patch to fix an assertion
failure when a non-exclusive pg_stop_backup is aborted.
Martín Marqués sent in two more revisions of a patch to make pg_basebackup use
Ildar Musin sent in a patch to remove the redundant IndexTupleDSize macro.
Masahiko Sawada sent in another revision of a patch to move relation extension
locks out of the heavyweight lock manager.
Alik Khilazhev and Fabien COELHO traded patches to add a Zipfian distribution to
Michaël Paquier and Peter Eisentraut traded patches to allow SSL connection from
a v11 client to a v10 server with SCRAM channel binding.
Torikoshi Atsushi sent in four revisions of a patch to ensure that old
ReorderBuffer spilled files are deleted.
Tomas Vondra sent in two revisions of a patch to implement a custom lz4
compression method atop Ildus Kurbangaliev's patch which enables such
高增琦 (GaoZengqi) sent in two more revisions of a patch to add a dependency
between client executables and static libraries.
Huong Dangminh sent in another revision of a patch to fix the slot_store error
Sophie Herold sent in a patch to add a pg_to_typemod() function.
Masahiko Sawada sent in another revision of a patch to correctly establish the
replication status with logical replication.
Alexander Korotkov sent in another revision of a patch to implement incremental
Amit Khandekar and Amit Langote traded patches to make UPDATE that changes a
partition key to another partition Just Work.
Amit Khandekar and Amul Sul traded patches to implement parallel Append.
Ildus Kurbangaliev sent in two more revisions of a patch to implement custom
Michaël Paquier sent in two more revisions of a patch to add a connection
parameter "saslchannelbinding" and implement channel binding
tls-server-end-point for SCRAM.
Kyotaro HORIGUCHI sent in another revision of a patch to show index scans of the
last vacuum in pg_stat_all_tables, and add vacuum_required, vacuum execution
status and truncation information to pg_stat_all_tables.
Jing Wang sent in another revision of a patch to implement COMMENT ON DATABASE
Thomas Munro sent in another revision of a patch to implement parallel hash.
Artur Zakirov sent in another revision of a patch to fix a bug in how
to_timestamp() worked in the case of an FX prefix.
Rushabh Lathia and Amit Langote traded patches to fix an issue where range
partition didn't handle NULL partition keys.
Amit Langote sent in another revision of a patch to make partition pruning
Rushabh Lathia sent in a patch to fix a typo in the
Jeevan Chalke sent in another revision of a patch to implement partition-wise
Nikhil Sontakke sent in another revision of a patch to implement logical
decoding of two-phase transactions.
Amul Sul sent in another revision of a patch to restrict concurrent
update/delete with UPDATE of partition key.
Amit Kapila and Rafia Sabih traded patches to speed up processing at Gather
Thomas Munro sent in another revision of a patch to support huge pages on
Amit Langote sent in a patch to allow ON CONFLICT DO NOTHING on partitioned
Etsuro Fujita sent in another revision of a patch to support tuple routing for
Antonin Houska sent in another revision of a patch to enable separate logging
Pavel Stěhule sent in another revision of a patch to add default namespaces for
Oliver Ford sent in a patch to add RANGE with values and exclusions clauses to
the Window Functions.
Michaël Paquier sent in another revision of a patch to refactor syscache
routines to get attribute name, extend lookup routines for FDW and foreign
server with NULL handling, refactor routines for subscription and publication
lookups, and eliminate user-visible cache lookup errors for objaddr SQL
Fabien COELHO sent in a patch to add \if to pgbench.
Tomas Vondra sent in a patch to fix an issue in multivariate histograms and MCV
Mark Dilger sent in two revisions of a patch to clean up some code in
Hadi Moshayedi sent in a patch to fix a crash in int8_avg_combine().
Yura Sokolov sent in another revision of a patch to fix performance degradation
of contended LWLock on NUMA.
|Next Message||David Fetter||2017-12-03 19:31:08||== PostgreSQL Weekly News - December 03 2017 ==|
|Previous Message||Bo Peng||2017-11-22 04:29:37||Pgpool-II 3.7.0 and pgpoolAdmin 3.7.0 are now relased.|