== PostgreSQL Weekly News - June 28 2015 == - Mailing list pgsql-announce

== PostgreSQL Weekly News - June 28 2015 ==

PGConf.DE will be held November 26-27 in Hamburg, Germany, at the
Lindner Hotel am Michel.  The CfP is open until September 13, 2015.
http://2015.pgconf.de/

== PostgreSQL Product News ==

HypoPG, hypothetical indexes for PostgreSQL, released.
https://github.com/dalibo/hypopg

par_psql v0.1: 'Parallel psql', which adds special markings for
queries to be run in parallel, released.
http://github.com/gbb/par_psql/

== PostgreSQL Jobs for June ==

http://archives.postgresql.org/pgsql-jobs/2015-06/threads.php

== PostgreSQL Local ==

PGDay UK, Conference will be taking place on 7th July 2015 – it is aimed at
the UK PostgreSQL Community.  The CfP is open until 13 April 2015.
http://www.postgresqlusergroup.org.uk

PGDay Campinas 2015 will take place in Campinas on August 7.
http://pgdaycampinas.com.br/english/

The Call For Papers for PostgresOpen 2015, being held in Dallas, Texas
from September 16th to 18th, is now open.
http://2015.postgresopen.org/callforpapers/

PostgreSQL Session #7, will be held September 24th, 2015 in Paris,
France,
http://www.postgresql-sessions.org/7/about

PostgreSQL Conference Europe 2015 will be held on October 27-30 in the
Vienna Marriott Hotel, in Vienna, Austria.  The CfP is open until
August 7.
http://2015.pgconf.eu/

PGConf Silicon Valley 2015 is November 17-18 at the South San
Francisco Convention Center.  Discount registration is available
through June 30.
http://www.pgconfsv.com

PGBR2015 (The Brazilian PostgreSQL Conference) will take place in Porto
Alegre, Rio Grande do Sul, on November 18, 19 and 20.
The CfP is open through July 15.
http://pgbr.postgresql.org.br/2015/en/#call-for-papers

== 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 Pacific time.
Please send English language ones to david@fetter.org, German language
to pwn@pgug.de, Italian language to pwn@itpug.org.  Spanish language
to pwn@arpug.com.ar.

== Applied Patches ==

Noah Misch pushed:

- Truncate strings in tarCreateHeader() with strlcpy(), not sprintf().
  This supplements the GNU libc bug #6530 workarounds introduced in
  commit 54cd4f04576833abc394e131288bf3dd7dcf4806.  On affected
  systems, a tar-format pg_basebackup failed when some filename
  beneath the data directory was not valid character data in the
  postmaster/walsender locale.  Back-patch to 9.1, where pg_basebackup
  was introduced.  Extant, bug-prone conversion specifications receive
  only ASCII bytes or involve low-importance messages.
  http://git.postgresql.org/pg/commitdiff/4318118edd5582696027f357771e0a8b091fe2bf

Robert Haas pushed:

- psql: Add some tab completion for TABLESAMPLE.  Petr Jelinek,
  reviewed by Brendan Jurd
  http://git.postgresql.org/pg/commitdiff/da9ee026a0ddd100785b00defd1201b317c0797b

- Update get_relation_info comment.  Thomas Munro
  http://git.postgresql.org/pg/commitdiff/51d0fe5d5682a65e3bce7aa62d8666509fd08aa2

- Allow background workers to connect to no particular database.  The
  documentation claims that this is supported, but it didn't actually
  work.  Fix that.  Reported by Pavel Stehule; patch by me.
  http://git.postgresql.org/pg/commitdiff/f7bb7f0625771bc71869cdadafcf54450b2db08f

- Improve handling of CustomPath/CustomPlan(State) children.  Allow
  CustomPath to have a list of paths, CustomPlan a list of plans, and
  CustomPlanState a list of planstates known to the core system, so
  that custom path/plan providers can more reasonably use this
  infrastructure for nodes with multiple children.  KaiGai Kohei, per
  a design suggestion from Tom Lane, with some further kibitzing by
  me.
  http://git.postgresql.org/pg/commitdiff/5ca611841bcd37c7ee8448c46c8398ef8d8edcc4

- Reduce log level for background worker events from LOG to DEBUG1.
  Per discussion, LOG is just too chatty for something that will
  happen as routinely as this.  Pavel Stehule
  http://git.postgresql.org/pg/commitdiff/91118f1a59f2038f072552fdbb98e01363e30b59

- Don't warn about creating temporary or unlogged hash indexes.
  Warning people that no WAL-logging will be done doesn't make sense
  in this case.  Michael Paquier
  http://git.postgresql.org/pg/commitdiff/9043ef390f4f0b4586cfe59cbd22314b9c3e2957

- release notes: Combine items for pg_upgrade and pg_upgrade_support
  moves.  Per suggestions from Amit Langote and Álvaro Herrera.
  http://git.postgresql.org/pg/commitdiff/31c018ecda9f40fe80055d8ba95248c023593fb4

- Remove unnecessary NULL test.  Spotted by Coverity and reported by
  Michael Paquier.  Per discussion, we don't necessarily care about
  making Coverity happy in all such instances, but we can go ahead and
  change them where it otherwise seems to improve the code.
  http://git.postgresql.org/pg/commitdiff/8a8c581a8c99b9beecbdc517957da866f427f297

- release notes: Add entry for commit 5ea86e6e6.  Peter Geoghegan and
  Robert Haas
  http://git.postgresql.org/pg/commitdiff/c66bc72e8a1318e43ea657ffa3798fa95f491650

- Be more conservative about removing tablespace "symlinks".  Don't
  apply rmtree(), which will gleefully remove an entire subtree, and
  don't even apply unlink() unless it's symlink or a directory, the
  only things that we expect to find.  Amit Kapila, with minor tweaks
  by me, per extensive discussions involving Andrew Dunstan, Fujii
  Masao, and Heikki Linnakangas, at least some of whom also reviewed
  the code.
  http://git.postgresql.org/pg/commitdiff/8f15f74a44f68f9cb3a644786d3c732a5eeb237a

- Fix grammar.  Reported by Peter Geoghegan.
  http://git.postgresql.org/pg/commitdiff/7c02d48e698ad38bec1399a9dcc543c80b8f5b8f

Tom Lane pushed:

- Improve inheritance_planner()'s performance for large inheritance
  sets.  Commit c03ad5602f529787968fa3201b35c119bbc6d782 introduced a
  planner performance regression for UPDATE/DELETE on large
  inheritance sets.  It required copying the append_rel_list (which is
  of size proportional to the number of inherited tables) once for
  each inherited table, thus resulting in O(N^2) time and memory
  consumption.  While it's difficult to avoid that in general, the
  extra work only has to be done for append_rel_list entries that
  actually reference subquery RTEs, which inheritance-set entries will
  not.  So we can buy back essentially all of the loss in cases
  without subqueries in FROM; and even for those, the added work is
  mainly proportional to the number of UNION ALL subqueries.
  Back-patch to 9.2, like the previous commit.  Tom Lane and Dean
  Rasheed, per a complaint from Thomas Munro.
  http://git.postgresql.org/pg/commitdiff/2cb9ec1bcb35dd6b4cf7a4a325aaa9791444e69d

- Docs: fix claim that to_char('FM') removes trailing zeroes.  Of
  course, what it removes is leading zeroes.  Seems to have been a
  thinko in commit ffe92d15d53625d5ae0c23f4e1984ed43614a33d.  Noted by
  Hubert Depesz Lubaczewski.
  http://git.postgresql.org/pg/commitdiff/d759b7eb6aee12bd52516905d790072845b4356f

- Fix the logic for putting relations into the relcache init file.
  Commit f3b5565dd4e59576be4c772da364704863e6a835 was a couple of
  bricks shy of a load; specifically, it missed putting
  pg_trigger_tgrelid_tgname_index into the relcache init file, because
  that index is not used by any syscache.  However, we have
  historically nailed that index into cache for performance reasons.
  The upshot was that load_relcache_init_file always decided that the
  init file was busted and silently ignored it, resulting in a
  significant hit to backend startup speed.  To fix, reinstantiate
  RelationIdIsInInitFile() as a wrapper around
  RelationSupportsSysCache(), which can know about additional
  relations that should be in the init file despite being unknown to
  syscache.c.  Also install some guards against future mistakes of
  this type: make write_relcache_init_file Assert that all nailed
  relations get written to the init file, and make
  load_relcache_init_file emit a WARNING if it takes the "wrong number
  of nailed relations" exit path.  Now that we remove the init files
  during postmaster startup, that case should never occur in the
  field, even if we are starting a minor-version update that added or
  removed rels from the nailed set.  So the warning shouldn't ever be
  seen by end users, but it will show up in the regression tests if
  somebody breaks this logic.  Back-patch to all supported branches,
  like the previous commit.
  http://git.postgresql.org/pg/commitdiff/5d1ff6bd559ea8df1b7302e245e690b01b9a4fa4

- Avoid passing NULL to memcmp() in lookups of zero-argument
  functions.  A few places assumed they could pass NULL for the
  argtypes array when looking up functions known to have zero
  arguments.  At first glance it seems that this should be safe
  enough, since memcmp() is surely not allowed to fetch any bytes if
  its count argument is zero.  However, close reading of the C
  standard says that such calls have undefined behavior, so we'd
  probably best avoid it.  Since the number of places doing this is
  quite small, and some other places looking up zero-argument
  functions were already passing dummy arrays, let's standardize on
  the latter solution rather than hacking the function lookup code to
  avoid calling memcmp() in these cases.  I also added Asserts to
  catch any future violations of the new rule.  Given the utter lack
  of any evidence that this actually causes any problems in the field,
  I don't feel a need to back-patch this change.  Per report from
  Piotr Stefaniak, though this is not his patch.
  http://git.postgresql.org/pg/commitdiff/0a52d378b03b7d5ab1d64627a87edaf5ed311c6c

Peter Eisentraut pushed:

- pg_rewind: Improve message wording
  http://git.postgresql.org/pg/commitdiff/e98d635d5dbf25e5cde282af111af9fdffafa557

- pg_basebackup: Remove redundant newline in error message
  http://git.postgresql.org/pg/commitdiff/747781f25e7eaa2e5cb5ed69bdae3e5f61795d2e

Heikki Linnakangas pushed:

- Add missing newline to debug-message.  Michael Paquier
  http://git.postgresql.org/pg/commitdiff/9cb36981fbbf2f298db2476101f4475c52d00fbb

- Fix a couple of bugs with wal_log_hints.  1. Replay of the WAL
  record for setting a bit in the visibility map contained an
  assertion that a full-page image of that record type can only occur
  with checksums enabled. But it can also happen with wal_log_hints,
  so remove the assertion. Unlike checksums, wal_log_hints can be
  changed on the fly, so it would be complicated to figure out if it
  was enabled at the time that the WAL record was generated.  2.
  wal_log_hints has the same effect on the locking needed to read the
  LSN of a page as data checksums. BufferGetLSNAtomic() didn't get the
  memo.  Backpatch to 9.4, where wal_log_hints was added.
  http://git.postgresql.org/pg/commitdiff/4b8e24b9ad308c30dbe2184e06848e638e018114

- Fix typo in comment.  Etsuro Fujita
  http://git.postgresql.org/pg/commitdiff/7845db2aa778aa751b41cff72c41c94993e975e3

- Add missing_ok option to the SQL functions for reading files.  This
  makes it possible to use the functions without getting errors, if
  there is a chance that the file might be removed or renamed
  concurrently.  pg_rewind needs to do just that, although this could
  be useful for other purposes too. (The changes to pg_rewind to use
  these functions will come in a separate commit.) The
  read_binary_file() function isn't very well-suited for
  extensions.c's purposes anymore, if it ever was. So bite the bullet
  and make a copy of it in extension.c, tailored for that use case.
  This seems better than the accidental code reuse, even if it's a
  some more lines of code.  Michael Paquier, with plenty of kibitzing
  by me.
  http://git.postgresql.org/pg/commitdiff/cb2acb1081e13b4b27a76c6b5311115528e49c59

- Don't choke on files that are removed while pg_rewind runs.  If a
  file is removed from the source server, while pg_rewind is running,
  the invocation of pg_read_binary_file() will fail. Use the
  just-added missing_ok option to that function, to have it return
  NULL instead, and handle that gracefully. And similarly for
  pg_ls_dir and pg_stat_file.  Reported by Fujii Masao, fix by Michael
  Paquier.
  http://git.postgresql.org/pg/commitdiff/b36805f3c54fe0e50e58bb9e6dad66daca46fbf6

- Fix double-XLogBeginInsert call in GIN page splits.  If data
  checksums or wal_log_hints is on, and a GIN page is split, the code
  to find a new, empty, block was called after having already called
  XLogBeginInsert(). That causes an assertion failure or PANIC, if
  finding the new block involves updating a FSM page that had not been
  modified since last checkpoint, because that update is WAL-logged,
  which calls XLogBeginInsert again. Nested XLogBeginInsert calls are
  not supported.  To fix, rearrange GIN code so that XLogBeginInsert
  is called later, after finding the victim buffers.  Reported by Jeff
  Janes.
  http://git.postgresql.org/pg/commitdiff/a45c70acf35e43257d86313dcbb7bb0e5201fab1

- Promote the assertion that XLogBeginInsert() is not called twice
  into ERROR.  Seems like cheap insurance for WAL bugs. A spurious
  call to XLogBeginInsert() in itself would be fairly harmless, but if
  there is any data registered and the insertion is not
  completed/cancelled properly, there is a risk that the data ends up
  in a wrong WAL record.  Per Jeff Janes's suggestion.
  http://git.postgresql.org/pg/commitdiff/a32c3ec893cafbd3a4b42c34270a80198f28f123

- Fix markup in docs.  Oops. I could swear I built the docs before
  pushing, but I guess not..
  http://git.postgresql.org/pg/commitdiff/6ab4d38ab085b0177d7ce63f7e1f2fb3f3a8e4a5

Fujii Masao pushed:

- Add index terms for functions jsonb_set and jsonb_pretty.
  http://git.postgresql.org/pg/commitdiff/0b157a0dad4f88f6f4420faa4cddab1e5112988f

Andres Freund pushed:

- Fix the fallback memory barrier implementation to be reentrant.
  This was essentially "broken" since 0c8eda62; but until more
  recently (14e8803f) barriers usage in signal handlers was
  infrequent.  The failure to be reentrant was noticed because the
  test_shm_mq, which uses memory barriers at a high frequency,
  occasionally got stuck on some solaris buildfarm animals. Turns out,
  those machines use sun studio 12.1, which doesn't yet have efficient
  memory barrier support. A machine with a newer sun studio did not
  fail.  Forcing the barrier fallback to be used on x86 allows to
  reproduce the problem.  The new fallback is to use
  kill(PostmasterPid, 0) based on the theory that that'll always imply
  a barrier due to checking the liveliness of PostmasterPid on systems
  old enough to need fallback support. It's hard to come up with a
  good and performant fallback.  I'm not backpatching this for now -
  the problem isn't active in the back branches, and we haven't
  backpatched barrier changes for now. Additionally master looks
  entirely different than the back branches due to the new atomics
  abstraction. It seems better to let this rest in master, where the
  non-reentrancy actively causes a problem, and then consider
  backpatching.  Found-By: Robert Haas Discussion:
  55626265.3060800@dunslane.net
  http://git.postgresql.org/pg/commitdiff/1b468a131bd260c9041484f78b8580c7f232d580

- Fix test_decoding's handling of nonexistant columns in old tuple
  versions.  test_decoding used fastgetattr() to extract column
  values. That's wrong when decoding updates and deletes if a table's
  replica identity is set to FULL and new columns have been added
  since the old version of the tuple was created. Due to the lack of a
  crosscheck with the datum's natts values an invalid value will be
  output, leading to errors or worse.  Bug: #13470 Reported-By:
  Krzysztof Kotlarski Discussion:
  20150626100333.3874.90852@wrigleys.postgresql.org Backpatch to 9.4,
  where the feature, including the bug, was added.
  http://git.postgresql.org/pg/commitdiff/d47a1136e441cebe7ae7fe72d70eb8ce278d5cd6

Álvaro Herrera pushed:

- Fix BRIN xlog replay.  There was a confusion about which block
  number to use when storing an item's pointer in the revmap -- the
  revmap page's blkno was being used, not the data page's blkno.
  Spotted-by: Jeff Janes
  http://git.postgresql.org/pg/commitdiff/402822246866e1094d35a617775a65b4be93d322

- Fix DDL command collection for TRANSFORM.  Commit b488c580ae, which
  added the DDL command collection feature, neglected to update the
  code that commit cac76582053e had previously added two weeks earlier
  for the TRANSFORM feature.  Reported by Michael Paquier.
  http://git.postgresql.org/pg/commitdiff/7d60b2af34842ae89b1abdd31fb5d303bd43c514

Simon Riggs pushed:

- Avoid hot standby cancels from VAC FREEZE VACUUM FREEZE generated
  false cancelations of standby queries on an otherwise idle master.
  Caused by an off-by-one error on cutoff_xid which goes back to
  original commit.  Backpatch to all versions 9.0+ Analysis and report
  by Marco Nenciarini Bug fix by Simon Riggs
  http://git.postgresql.org/pg/commitdiff/66fbcb0d2e1b201477dd2977b6eb93b1cfd9dd6c

Kevin Grittner pushed:

- Add opaque declaration of HTAB to tqual.h.  Commit
  b89e151054a05f0f6d356ca52e3b725dd0505e53 added the
  ResolveCminCmaxDuringDecoding declaration to tqual.h, which uses an
  HTAB parameter, without declaring HTAB.  It accidentally fails to
  fail to build with current sources because a declaration happens to
  be included, directly or indirectly, in all source files that
  currently use tqual.h before tqual.h is first included, but we
  shouldn't count on that.  Since an opaque declaration is enough
  here, just use that, as was done in snapmgr.h.  Backpatch to 9.4,
  where the HTAB reference was added to tqual.h.
  http://git.postgresql.org/pg/commitdiff/604e99396de02f6f23950ee373c13335d2ccdf05

- Fix comment for GetCurrentIntegerTimestamp().  The unit of measure
  is microseconds, not milliseconds.  Backpatch to 9.3 where the
  function and its comment were added.
  http://git.postgresql.org/pg/commitdiff/cca8ba9529f8815acd23fe88c32763765d0e1b68

Tatsuo Ishii pushed:

- Fix function declaration style to respect the coding standard.
  http://git.postgresql.org/pg/commitdiff/527e6d3f099df22783465ca7046fc0c8a534c921

== Rejected Patches (for now) ==

No one was disappointed this week :-)

== Pending Patches ==

Peter Geoghegan sent in a patch to allow JSON[B] arrays to take
negative subscripts.

Tomas Vondra sent in a patch to add density correction to sampling for
statistics collection.

Michael Paquier sent in a patch to fix some white space in pg_rewind
error messages.

Michael Paquier and Robert Haas traded patches to fix an issue where a
dangerous rm -rf was being issued in the global makefile.

Michael Paquier sent in two more revisions of a patch to update the
hash index creation warning.

Abhijit Menon-Sen sent in a patch to introduce
XLogLockBlockRangeForCleanup().

Fabien COELHO sent in another revision of a patch to add checkpointer
continuous flushing.

Michael Paquier sent in another revision of a patch to add support for
TAP tests on Windows.

Michael Paquier sent in a patch to improve log capture of TAP tests
and fix race conditions.

Fabrízio de Royes Mello sent in two more revisions of a patch to add
CINE for ALTER TABLE ... ADD COLUMN.

Uriy Zhuravlev sent in another revision of a patch to implement ALTER
OPERATOR.

Craig Ringer sent in a patch to implement ALTER TABLE ... ALTER
CONSTRAINT ... SET DEFERRABLE on UNIQUE or PK.

Oskari Saarenmaa sent in a patch to add -lrt to configure for
sched_yield on Solaris.

Jim Nasby sent in a patch to ensure that object_classes is properly
sized.

Marco Nenciarini sent in a patch to fix an off-by-one bug which caused
VACUUM FREEZE to mistakenly cancel standby sessions.

Peter Geoghegan sent in a patch to add some compatibility notes for
UPSERT with foreign data wrappers.

Amit Kapila sent in a patch to improve the performance of DROP TABLE
when the shared_buffers setting is high.

Jeff Janes sent in a patch to make pg_trgm perform better by
supporting the triconsistent function, introduced in version 9.4 of
the server, to make it faster to implement indexed queries where some
keys are common and some are rare.

Tom Lane sent in a patch to refactor the way the pg_file_settings view
works.