== PostgreSQL Weekly News - July 27 2014 ==
David Fetter <david <at> fetter.org>
2014-07-28 05:41:43 GMT
== PostgreSQL Weekly News - July 27 2014 ==
PostgreSQL 9.4 Beta 2 released. TEST!
PostgreSQL bug fix versions 9.3.5, 9.2.9, 9.1.14, 9.0.18, and 8.4.22
out now; 8.4 is now EOL.
== PostgreSQL Product News ==
Bi-Direction Replication (BDR), an asynchronous multi-master
replication system for PostgreSQL, has been announced by 2ndQuadrant.
pgAdmin3 v1.20.0 Beta 1, a multi-platform stand-alone GUI
administration tool, released.
== PostgreSQL Jobs for July ==
== PostgreSQL Local ==
PgDay Portland, Oregon 2014 will be held Saturday September 6, 2014.
Postgres Open 2014 will be in Chicago, IL, USA, September 17-19.
Tickets and Tutorials now available for purchase.
The 4th PgDay Ecuador will be held on Tuesday 7th in October at the
city of Quito, as part of the 5th International Congress of Free
Software. Send talk proposals to ecpug AT postgresql DOT org.
The sixth PGDay Cubano be held on 13 and 14 October 2014 in Habana.
PGConf.EU 2014 in Madrid, Spain on October 21-24 is now open for
PGDay.IT 2014 will take place in Prato on November the 7th 2014. The
International Call For Papers is now open:
== PostgreSQL in the News ==
Planet PostgreSQL: http://planet.postgresql.org/
PostgreSQL Weekly News is brought to you this week by David Fetter
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== Applied Patches ==
Peter Eisentraut pushed:
- Translation updates
- Update SQL features list
- gitattributes: Ignore time zone data files for whitespace checks.
The latest update introduced some funny whitespace, but since they
are externally maintained files, we add them to the list of files to
- Unset some local environment variables in TAP tests. Unset
environment variables that control message language, so that we can
compare some program output with expected strings. This is very
similar to what pg_regress does.
- Fix TAP installcheck tests when current directory name contains
spaces. This fixes the installcheck part. The check part has
additional problems that will be addressed in a separate commit.
- doc: Fix up ALTER TABLESPACE reference page. The documentation of
ALTER TABLESPACE ... MOVE was added without any markup, not even
paragraph breaks. Fix that, and clarify the text in a few places.
Magnus Hagander pushed:
- Properly use DEFAULT_EVENT_SOURCE in pgevent.c. This was broken and
reverted in a previous commit. The (this time verified) fix is to
simly add postgres_fe.h. MauMau, review by Amit Kapila
Tom Lane pushed:
- Defend against bad relfrozenxid/relminmxid/datfrozenxid/datminmxid
values. In commit a61daa14d56867e90dc011bbba52ef771cea6770, we
fixed pg_upgrade so that it would install sane relminmxid and
datminmxid values, but that does not cure the problem for
installations that were already pg_upgraded to 9.3; they'll
initially have "1" in those fields. This is not a big problem so
long as 1 is "in the past" compared to the current nextMultiXact
counter. But if an installation were more than halfway to the MXID
wrap point at the time of upgrade, 1 would appear to be "in the
future" and that would effectively disable tracking of oldest MXIDs
in those tables/databases, until such time as the counter wrapped
around. While in itself this isn't worse than the situation
pre-9.3, where we did not manage MXID wraparound risk at all, the
consequences of premature truncation of pg_multixact are worse now;
so we ought to make some effort to cope with this. We discussed
advising users to fix the tracking values manually, but that seems
both very tedious and very error-prone. Instead, this patch adopts
two amelioration rules. First, a relminmxid value that is "in the
future" is allowed to be overwritten with a full-table VACUUM's
actual freeze cutoff, ignoring the normal rule that relminmxid
should never go backwards. (This essentially assumes that we have
enough defenses in place that wraparound can never occur anymore,
and thus that a value "in the future" must be corrupt.) Second, if
we see any "in the future" values then we refrain from truncating
pg_clog and pg_multixact. This prevents loss of clog data until we
have cleaned up all the broken tracking data. In the worst case
that could result in considerable clog bloat, but in practice we
expect that relfrozenxid-driven freezing will happen soon enough to
fix the problem before clog bloat becomes intolerable. (Users could
do manual VACUUM FREEZEs if not.) Note that this mechanism cannot
save us if there are already-wrapped or already-truncated-away MXIDs
in the table; it's only capable of dealing with corrupt tracking
values. But that's the situation we have with the pg_upgrade bug.
For consistency, apply the same rules to relfrozenxid/datfrozenxid.
There are not known mechanisms for these to get messed up, but if
they were, the same tactics seem appropriate for fixing them.
- Adjust cutoff points in newly-added sanity tests. Per
recommendation from Andres Freund.
- Release notes for 9.3.5, 9.2.9, 9.1.14, 9.0.18, 8.4.22.
- Reject out-of-range numeric timezone specifications. In commit
631dc390f49909a5c8ebd6002cfb2bcee5415a9d, we started to handle
simple numeric timezone offsets via the zic library instead of the
old CTimeZone/HasCTZSet kluge. However, we overlooked the fact that
the zic code will reject UTC offsets exceeding a week (which seems a
bit arbitrary, but not because it's too tight ...). This led to
possibly setting session_timezone to NULL, which results in crashes
in most timezone-related operations as of 9.4, and crashes in a
small number of places even before that. So check for NULL return
from pg_tzset_offset() and report an appropriate error message. Per
bug #11014 from Duncan Gillis. Back-patch to all supported
branches, like the previous patch. (Unfortunately, as of today that
no longer includes 8.4.)
- Check block number against the correct fork in get_raw_page().
get_raw_page tried to validate the supplied block number against
RelationGetNumberOfBlocks(), which of course is only right when
accessing the main fork. In most cases, the main fork is longer
than the others, so that the check was too weak (allowing a
lower-level error to be reported, but no real harm to be done).
However, very small tables could have an FSM larger than their heap,
in which case the mistake prevented access to some FSM pages. Per
report from Torsten Foertsch. In passing, make the bad-block-number
error into an ereport not elog (since it's certainly not an internal
error); and fix sloppily maintained comment for
RelationGetNumberOfBlocksInFork. This has been wrong since we
invented relation forks, so back-patch to all supported branches.
- Re-enable error for "SELECT ... OFFSET -1". The executor has thrown
errors for negative OFFSET values since 8.4 (see commit
bfce56eea45b1369b7bb2150a150d1ac109f5073), but in a moment of brain
fade I taught the planner that OFFSET with a constant negative value
was a no-op (commit 1a1832eb085e5bca198735e5d0e766a3cb61b8fc).
Reinstate the former behavior by only discarding OFFSET with a value
of exactly 0. In passing, adjust a planner comment that referenced
the ancient behavior. Back-patch to 9.3 where the mistake was
- Rearrange documentation paragraph describing pg_relation_size().
Break the list of available options into an <itemizedlist> instead
of inline sentences. This is mostly motivated by wanting to ensure
that the cross-references to the FSM and VM docs don't cross page
boundaries in PDF format; but it seems to me to read more easily
this way anyway. I took the liberty of editorializing a bit further
while at it. Per complaint from Magnus about 9.0.18 docs not
building in A4 format. Patch all active branches so we don't get
blind-sided by this particular issue again in future.
- Fix a performance problem in pg_dump's dump order selection logic.
findDependencyLoops() was not bright about cases where there are
multiple dependency paths between the same two dumpable objects. In
most scenarios this did not hurt us too badly; but since the
introduction of section boundary pseudo-objects in commit
a1ef01fe163b304760088e3e30eb22036910a495, it was possible for this
code to take unreasonable amounts of time (tens of seconds on a
database with a couple thousand objects), as reported in bug #11033
from Joe Van Dyk. Joe's particular problem scenario involved
"pg_dump -a" mode with long chains of foreign key constraints, but I
think that similar problems could arise with other situations as
long as there were enough objects. To fix, add a flag array that
lets us notice when we arrive at the same object again while
searching from a given start object. This simple change seems to be
enough to eliminate the performance problem. Back-patch to 9.1,
like the patch that introduced section boundary objects.
Noah Misch pushed:
- Diagnose incompatible OpenLDAP versions during build and test. With
OpenLDAP versions 2.4.24 through 2.4.31, inclusive, PostgreSQL
backends can crash at exit. Raise a warning during "configure"
based on the compile-time OpenLDAP version number, and test the
crash scenario in the dblink test suite. Back-patch to 9.0 (all
- MSVC: Substitute $(top_builddir) in REGRESS_OPTS. Commit
d7cdf6ee36adeac9233678fb8f2a112e6678a770 introduced a usage thereof.
Back-patch to 9.0, like that commit.
- Report success when Windows kill() emulation signals an exiting
process. This is consistent with the POSIX verdict that kill()
shall not report ESRCH for a zombie process. Back-patch to 9.0 (all
supported versions). Test code from commit
d7cdf6ee36adeac9233678fb8f2a112e6678a770 depends on it, and log
messages about kill() reporting "Invalid argument" will cease to
appear for this not-unexpected condition.
- Move PGAC_LDAP_SAFE to config/programs.m4. This restores the style
of keeping configure.in free of AC_DEFUN. Per gripe from Tom Lane.
- Handle WAIT_IO_COMPLETION return from WaitForMultipleObjectsEx().
This return code is possible wherever we pass bAlertable = TRUE; it
arises when Windows caused the current thread to run an "I/O
completion routine" or an "asynchronous procedure call". PostgreSQL
does not provoke either of those Windows facilities, hence this bug
remaining largely unnoticed, but other local code might do so. Due
to a shortage of complaints, no back-patch for now. Per report from
Shiv Shivaraju Gowda, this bug can cause PGSemaphoreLock() to PANIC.
The bug can also cause select() to report timeout expiration too
early, which might confuse pgstat_init() and CheckRADIUSAuth().
Andrew Dunstan pushed:
- Allow empty string object keys in json_object(). This makes the
behaviour consistent with the json parser, other json-generating
functions, and the JSON standards.
Fujii Masao pushed:
- Fix bug where pg_receivexlog goes into busy loop if -s option is set
to 0. The problem is that pg_receivexlog calls select(2) with
timeout=0 and goes into busy loop when --status-interval option is
set to 0. This bug was introduced by the commit,
74cbe966fe2d76de1d607d933c98c144dab58769. Per report from Sawada
Robert Haas pushed:
- docs: Improve documentation of \pset without arguments. The syntax
summary previously failed to clarify that the first argument is also
optional. The textual description did mention it, but all the way
at the bottom. It fits better with the command overview, so move it
there, and fix the summary also. Dilip Kumar, reviewed by Fabien
- Avoid access to already-released lock in LockRefindAndRelease.
Spotted by Tom Lane.
- Prevent shm_mq_send from reading uninitialized memory.
shm_mq_send_bytes didn't invariably initialize *bytes_written before
returning, which would cause shm_mq_send to read from uninitialized
memory and add the value it found there to mqh->mqh_partial_bytes.
This could cause the next attempt to send a message via the queue to
fail an assertion (if the queue was detached) or copy data from a
garbage pointer value into the queue (if non-blocking mode was in
- Fix checkpointer crash in EXEC_BACKEND builds. Nothing in the
checkpointer calls InitXLOGAccess(), so WALInsertLocks never got
initialized there. Without EXEC_BACKEND, it works anyway because
the correct value is inherited from the postmaster, but with
EXEC_BACKEND we've got a problem. The problem appears to have been
introduced by commit 68a2e52bbaf98f136a96b3a0d734ca52ca440a95. To
fix, move the relevant initialization steps from InitXLOGAccess() to
XLOGShmemInit(), making this more parallel to what we do elsewhere.
Andres Freund pushed:
- Properly remove ephemeral replication slots after a crash restart.
Ephemeral slots - slots that shouldn't survive database restarts -
weren't properly cleaned up after a immediate/crash restart. They
were ignored in the sense that they weren't restored into memory and
thus didn't cause unwanted resource retention; but they prevented a
new slot with the same name from being created. Now ephemeral slots
are fully removed during startup. Backpatch to 9.4 where
replication slots where added.
== Rejected Patches (for now) ==
No one was disappointed this week
== Pending Patches ==
Dilip Kumar sent in another revision of a patch to document correctly
that all arguments to pset are optional, not just the second.
Marko (johto) Tiikkaja sent in a patch to add
Anastasia Lubennikova sent in another revision of a patch to allow
index-only scans for multicolumn GiST.
Fabien COELHO and Mitsumasa KONDO traded patches to allow pgbench to
use a Gaussian distribution.
Kaigai Kouhei sent in another revision of a patch to enable the custom
Pavel Stehule sent in another revision of a patch to enable psql
unicode border line styles.
Viswanatham Kirankumar sent in another revision of a patch to process
pg_hba.conf keywords as case-insensitive.
Fabrízio de Royes Mello sent in two more revisions of a patch to
enable ALTER TABLE ... SET LOGGED.
Kyotaro HORIGUCHI sent in another revision of a patch to enable using
unique indexes for longer pathkeys.
Michael Paquier sent in a patch to add a facility to check
Full-Page-Write consistency at WAL replay.
Thomas Munro sent in four more revisions of a patch to implement SKIP
Fabrízio de Royes Mello sent in another revision of a patch to fix an
issue where the verbose output of pg_dump did not show schema names.
Furuya Osamu sent in another revision of a patch to add a synchronous
mode to pg_receivexlog.
Kyotaro HORIGUCHI sent in a patch to introduce coarse-grained
parallelism via the postgres_fdw.
Alexey Klyukin sent in a patch to implement subject alternative names
support for SSL connections.
Robert Haas sent in a patch to implement a contrib module that lets
you launch arbitrary command in a background worker, and supporting
infrastructure patches for core.
Guillaume Lelarge sent in a patch to fix the documentation for
Marko (johto) Tiikkaja sent in a patch to implement EXIT USING
Marko (johto) Tiikkaja sent in a patch to make PL/pgsql throw an error
during compilation (instead of runtime) if the number of parameters
passed to RAISE don't match the number of placeholders in error
Haribabu Kommi sent in another revision of a patch to enable min/max
on inet types.
David Rowley sent in a patch to fix an issue where get_loop_count()
fails to ignore RELOPT_DEADREL rels.
Peter Geoghegan sent in another revision of a patch to add a strxfrm()
optimization for B-Trees.
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