== PostgreSQL Weekly News – August 06 2012 ==
== PostgreSQL Weekly News – August 06 2012 ==
PostgreSQL 9.2 Beta 3 released.
The Call for Papers deadline for pgconf.eu 2012 has been extended.
Instead of ending tomorrow, the new deadline is Tuesday, August 7th,
== PostgreSQL Product News ==
pgpool-II 3.2.0, a multi-purpose middleware which can
provide connection pooling, replication, load balancing, parallel
execution and more, released.
pgpoolAdmin 3.2.0, a UI for pgpool, released.
== PostgreSQL Jobs for August ==
== PostgreSQL Local ==
PostgreSQL Session will be held on October 4th, 2012, in Paris,
France. More information at:
PostgreSQL Conference Europe 2012 will be in Prague, Czech Republic
on October 23-26. The call for papers is open.
PostgreSQL Day Argentina 2012 will be held on November 13th in Bernal,
Buenos Aires, at the National University of Quilmes. It will cover
topics for PostgreSQL users, developers and contributors, as well as
decision and policy makers. For more information about the
conference, please see the website at
== 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 ==
Bruce Momjian pushed:
– Now that the diskchecker.pl author has updated the download link on
his website, revert the separate link to the download git
repository. Backpatch from 9.0 to current.
– In pg_upgrade, use pg_log() instead of prep_status() for
newline-terminated messages, per suggestion from Tom. Backpatch to
– Document that, for psql -c, only the result of the last command is
returned, per report from Aleksey Tsalolikhin Backpatch to 9.2 and
– Document that trying to exceed temp_file_limit causes a query
cancel. Backpatch to 9.2.
– Add link to synchronous_commit variables in high availability docs.
Backpatch to 9.2. Erik Rijkers
– Reword documentation for concurrent index rebuilds to be clearer.
Backpatch to 9.1 and 9.2.
– Replace pgindent shell script with Perl script. Update perltidy
instructions to perltidy Perl files that lack Perl file extensions.
pgindent Perl coding by Andrew Dunstan, restructured by me.
Alvaro Herrera pushed:
– pg_basebackup: stylistic adjustments. The most user-visible part of
this is to change the long options –statusint and –noloop to
–status-interval and –no-loop, respectively, per discussion.
Also, consistently enclose file names in double quotes, per our
conventions; and consistently use the term “transaction log file” to
talk about WAL segments. (Someday we may need to go over this
terminology and make it consistent across the whole source code.)
Finally, reflow the code to better fit in 80 columns, and have
pgindent fix it up some more.
– Fix memory and file descriptor leaks in pg_receivexlog/pg_basebackup.
When the internal loop mode was added, freeing memory and closing
filedescriptors before returning became important, and a few cases
in the code missed that. This is a backpatch of commit 058a050e to
the 9.2 branch, which seems to have been neglected (in error,
because the bugs it fixes were introduced in commit 16282ae6 which
is present in both master and 9.2). Fujii Masao
– Make strings identical
Tom Lane pushed:
– Fix syslogger so that log_truncate_on_rotation works in the first
rotation. In the original coding of the log rotation stuff, we did
not bother to make the truncation logic work for the very first
rotation after postmaster start (or after a syslogger crash and
restart). It just always appended in that case. It did not seem
terribly important at the time, but we’ve recently had two separate
complaints from people who expected it to work unsurprisingly.
(Both users tend to restart the postmaster about as often as a log
rotation is configured to happen, which is maybe not typical use,
but still…) Since the initial log file is opened in the
postmaster, fixing this requires passing down some more state to the
syslogger child process. It’s always been like this, so back-patch
to all supported branches.
– Fix WITH attached to a nested set operation
(UNION/INTERSECT/EXCEPT). Parse analysis neglected to cover the
case of a WITH clause attached to an intermediate-level set
operation; it only handled WITH at the top level or WITH attached to
a leaf-level SELECT. Per report from Adam Mackler. In HEAD, I
rearranged the order of SelectStmt’s fields to put withClause with
the other fields that can appear on non-leaf SelectStmts. In back
branches, leave it alone to avoid a possible ABI break for
third-party code. Back-patch to 8.4 where WITH support was added.
– Add documentation cross-reference for JSON functions. Thom Brown
– Replace libpq’s “row processor” API with a “single row” mode. After
taking awhile to digest the row-processor feature that was added to
libpq in commit 92785dac2ee7026948962cd61c4cd84a2d052772, we’ve
concluded it is over-complicated and too hard to use. Leave the
core infrastructure changes in place (that is, there’s still a row
processor function inside libpq), but remove the exposed API pieces,
and instead provide a “single row” mode switch that causes
PQgetResult to return one row at a time in separate PGresult
objects. This approach incurs more overhead than proper use of a
row processor callback would, since construction of a PGresult per
row adds extra cycles. However, it is far easier to use and harder
to break. The single-row mode still affords applications the
primary benefit that the row processor API was meant to provide,
namely not having to accumulate large result sets in memory before
processing them. Preliminary testing suggests that we can probably
buy back most of the extra cycles by micro-optimizing construction
of the extra results, but that task will be left for another day.
– Update release notes for libpq feature change.
– Fix race conditions associated with SPGiST redirection tuples. The
correct test for whether a redirection tuple is removable is whether
tuple’s xid < RecentGlobalXmin, not OldestXmin; the previous coding
failed to protect index searches being done in concurrent
transactions that have no XID. This mirrors the recent fix in
btree’s page recycling logic made in commit
d3abbbebe52eb1e59e621c880ad57df9d40d13f2. Also, WAL-log the newest
XID of any removed redirection tuple on an index page, and apply
ResolveRecoveryConflictWithSnapshot during InHotStandby WAL replay.
This protects against concurrent Hot Standby transactions possibly
needing to see the redirection tuple(s). Per my query of 2012-03-12
and subsequent discussion.
– Stamp 9.2beta3.
– In SPGiST replay, do conflict resolution before modifying the page.
In yesterday’s commit 962e0cc71e839c58fb9125fa85511b8bbb8bdbee, I
added the ResolveRecoveryConflictWithSnapshot call in the wrong
place. I correctly put it before spgRedoVacuumRedirect itself would
modify the index page — but not before RestoreBkpBlocks, so replay
of a record with a full-page image would modify the page before
kicking off any conflicting HS transactions. Oops.
– Improve underdocumented btree_xlog_delete_get_latestRemovedXid()
code. As noted by Noah Misch, btree_xlog_delete_get_latestRemovedXid
is critically dependent on the assumption that it’s examining a
consistent state of the database. This was undocumented though, so
the seemingly-unrelated check for no active HS sessions might be
thought to be merely an optional optimization. Improve comments,
and add an explicit check of reachedConsistency just to be sure.
This function returns InvalidTransactionId (thereby killing all HS
transactions) in several cases that are not nearly unlikely enough
for my taste. This commit doesn’t attempt to fix those
deficiencies, just document them. Back-patch to 9.2, not from any
real functional need but just to keep the branches more closely
synced to simplify possible future back-patching.
– Fix bugs with parsing signed hh:mm and hh:mm:ss fields in interval
input. DecodeInterval() failed to honor the “range” parameter (the
special SQL syntax for indicating which fields appear in the literal
string) if the time was signed. This seems inappropriate, so make
it work like the not-signed case. The inconsistency was introduced
in my commit f867339c0148381eb1d01f93ab5c79f9d10211de, which as
noted in its log message was only really focused on making
SQL-compliant literals work per spec. Including a sign here is not
per spec, but if we’re going to allow it then it’s reasonable to
expect it to work like the not-signed case. Also, remove bogus
setting of tmask, which caused subsequent processing to think that
what had been given was a timezone and not an hh:mm(:ss) field, thus
confusing checks for redundant fields. This seems to be an
aboriginal mistake in Lockhart’s commit
2cf1642461536d0d8f3a1cf124ead0eac04eb760. Add regression test cases
to illustrate the changed behaviors. Back-patch as far as 8.4,
where support for spec-compliant interval literals was added. Range
problem reported and diagnosed by Amit Kapila, tmask problem by me.
Heikki Linnakangas pushed:
– Perform conversion from Python unicode to string/bytes object via
UTF-8. We used to convert the unicode object directly to a string
in the server encoding by calling Python’s PyUnicode_AsEncodedString
function. In other words, we used Python’s routines to do the
encoding. However, that has a few problems. First of all, it
required keeping a mapping table of Python encoding names and
PostgreSQL encodings. But the real killer was that Python doesn’t
support EUC_TW and MULE_INTERNAL encodings at all. Instead, convert
the Python unicode object to UTF-8, and use PostgreSQL’s encoding
conversion functions to convert from UTF-8 to server encoding. We
were already doing the same in the other direction in
PLyUnicode_FromString, so this is more consistent, too. Note: This
makes SQL_ASCII to behave more leniently. We used to map SQL_ASCII
to Python’s ‘ascii’, which on Python means strict 7-bit ASCII only,
so you got an error if the python string contained anything but pure
ASCII. You no longer get an error; you get the UTF-8 representation
of the string instead. Backpatch to 9.0, where these conversions
were introduced. Jan Urbański
– Put back plpython_unicode_2.out for SQL_ASCII case. This
alternative expected output file is required when using SQL_ASCII as
the client and server encoding. The python encoding conversion used
to throw an error on that, but it is now accepted and you get the
UTF-8 representation of the string. I thought that case was already
covered by the other expected output files, but the buildfarm says
otherwise. This is only required on REL9_2_STABLE. In 9.1, we
explicitly set client_encoding to UTF-8 to avoid this.
Magnus Hagander pushed:
– Complain with proper error message if streaming stops prematurely.
In particular, with a controlled shutdown of the master,
pg_basebackup with streaming log could terminate without an error
message, even though the backup is not consistent. In passing, fix
a few cases where walfile wasn’t properly set to -1 after closing.
Robert Haas pushed:
– Warn more vigorously about the non-transactional behavior of
sequences. Craig Ringer, edited fairly heavily by me.
– Typo fixes for previous commit. Noted by Thom Brown.
== Rejected Patches (for now) ==
No one was disappointed this week
== Pending Patches ==
Alvaro Herrera sent in another revision of the patch to make NOT NULL
constraints visible in pg_catalog.
Qi Huang sent in another revision of the patch to add a
Amit Kapila sent in a patch to compute the max LSN of data pages.
Marco Nenciarini sent in another revision of the patch to allow array
elements to be enforced foreign keys. The new syntax in the patch is
Fabian Coelho sent in two revisions of a patch to make psql -1 < file
work just as psql -1f file does, i.e. attempt to run the entire
contents of STDIN as one transaction.
Etsuro Fujita sent in a patch to allow the sortedness of CSV tables to
be used in planning for the file_fdw.
Amit Kapila sent in a PoC patch to reduce the amount of WAL generated
Alexander Korotkov sent in a patch to collect statistics and
selectivity estimation for ranges.
Tom Lane sent in a WIP patch to add LATERAL, and there was much rejoicing.
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