== PostgreSQL Weekly News - April 29 2007 ==

От: David Fetter
Тема: == PostgreSQL Weekly News - April 29 2007 ==
Дата: ,
Msg-id: 20070430041151.GA22226@fetter.org
(см: обсуждение, исходный текст)
Список: pgsql-announce

== PostgreSQL Weekly News - April 29 2007 ==

Security releases 8.2.4, 8.1.9, 8.0.13, 7.4.17 and 7.3.19 are out.
Schedule that upgrade now :)

== PostgreSQL Product News ==

EnterpriseDB 8.2 released.

A full-text dictionary for Italian released under the GPL.

Continuent Uni/Cluster for PostgreSQL 2007 released.

== PostgreSQL Jobs for April ==


== PostgreSQL Local ==

Get on the Road to PgDay!

Registration is open for PGCon 2007

== PostgreSQL in the News ==

Planet PostgreSQL: http://www.planetpostgresql.org/

General Bits, Archives and occasional new articles:

PostgreSQL Weekly News is brought to you this week by David Fetter

To get your submission into the upcoming issue, make sure it arrives
at  or in German at  by Sunday at 3:00pm
Pacific Time.

== Applied Patches ==

Michael Meskes committed:

- Removed non-existant function from extern.h

- Inlined two functions to get rid of va_list problems on some archs.

Tom Lane committed:

- Implement rate-limiting logic on how often backends will attempt to
  send messages to the stats collector.  This avoids the problem that
  enabling stats_row_level for autovacuum has a significant overhead
  for short read-only transactions, as noted by Arjen van der Meijden.
  We can avoid an extra gettimeofday call by piggybacking on the one
  done for WAL-logging xact commit or abort (although that doesn't
  help read-only transactions, since they don't WAL-log anything).  In
  my proposal for this, I noted that we could change the WAL log
  entries for commit/abort to record full TimestampTz precision,
  instead of only time_t as at present.  That's not done in this
  patch, but will be committed separately.

- Marginal performance hack: use a dedicated routine instead of
  copyObject to copy nodes that are known to be Vars during plan
  reference adjustment.  Saves useless memzero operation as well as
  the big switch in copyObject.

- Marginal performance hack: avoid unnecessary work in
  expression_tree_mutator.  We can just palloc, instead of using
  makeNode, when we are going to overwrite the whole node anyway in
  the FLATCOPY macro.  Also, use FLATCOPY instead of copyObject for
  common node types Var and Const.

- Marginal performance hack: remove the loop that used to be needed to
  look through a freelist for a chunk of adequate size.  For a long
  time now, all elements of a given freelist have been exactly the
  same allocated size, so we don't need a loop.  Since the loop never
  iterated more than once, you'd think this wouldn't matter much, but
  it makes a noticeable savings in a simple test --- perhaps because
  the compiler isn't optimizing on a mistaken assumption that the loop
  would repeat.  AllocSetAlloc is called often enough that saving even
  a couple of instructions is worthwhile.

- Modify processing of DECLARE CURSOR and EXPLAIN so that they can
  resolve the types of unspecified parameters when submitted via
  extended query protocol.  This worked in 8.2 but I had broken it
  during plancache changes.  DECLARE CURSOR is now treated almost
  exactly like a plain SELECT through parse analysis, rewrite, and
  planning; only just before sending to the executor do we divert it
  away to ProcessUtility.  This requires a special-case check in a
  number of places, but practically all of them were already
  special-casing SELECT INTO, so it's not too ugly.  (Maybe it would
  be a good idea to merge the two by treating IntoClause as a form of
  utility statement?  Not going to worry about that now, though.)
  That approach doesn't work for EXPLAIN, however, so for that I
  punted and used a klugy solution of running parse analysis an extra
  time if under extended query protocol.

- Fix dynahash.c to suppress hash bucket splits while a
  hash_seq_search() scan is in progress on the same hashtable.  This
  seems the least invasive way to fix the recently-recognized problem
  that a split could cause the scan to visit entries twice or (with
  much lower probability) miss them entirely.  The only field-reported
  problem caused by this is the "failed to re-find shared lock object"
  PANIC in COMMIT PREPARED reported by Michel Dorochevsky, which was
  caused by multiply visited entries.  However, it seems certain that
  mdsync() is vulnerable to missing required fsync's due to missed
  entries, and I am fearful that RelationCacheInitializePhase2() might
  be at risk as well.  Because of that and the generalized hazard
  presented by this bug, back-patch all the supported branches.  Along
  the way, fix pg_prepared_statement() and pg_cursor() to not assume
  that the hashtables they are examining will stay static between
  calls.  This is risky regardless of the newly noted dynahash
  problem, because hash_seq_search() has never promised to cope with
  deletion of table entries other than the just-returned one.  There
  may be no bug here because the only supported way to call these
  functions is via ExecMakeTableFunctionResult() which will cycle them
  to completion before doing anything very interesting, but it seems
  best to get rid of the assumption.  This affects 8.2 and HEAD only,
  since those functions weren't there earlier.

- Support explicit placement of the temporary-table schema within
  search_path.  This is needed to allow a security-definer function to
  set a truly secure value of search_path.  Without it, a malicious
  user can use temporary objects to execute code with the privileges
  of the security-definer function.  Even pushing the temp schema to
  the back of the search path is not quite good enough, because a
  function or operator at the back of the path might still capture
  control from one nearer the front due to having a more exact
  datatype match.  Hence, disable searching the temp schema altogether
  for functions and operators.  Security: CVE-2007-2138

Bruce Momjian committed:

- Update TODO, change version number, "Make
  standard_conforming_strings the default in 8.4?"

- In TODO, mark "PL/PgSQL MOVE" as done.

- Remove tabs from installation.sgml.

- Jun Kuwamura's update to the Japanese FAQs.

- Fix typo in FAQ.

- Update FAQ item on upgrades.

Magnus Hagander committed:

- In pgsql/src/tools/msvc/Mkvcbuild.pm, properly set MODULE_PATHNAME
  based on module name instead of incorrectly based on directory name.
  Fixes the generation of .sql files in contrib/spi.  Per complaint
  from Dave Page.

- In pgsql/src/tools/msvc/Mkvcbuild.pm, libpgtypes is a client lib,
  should not link with backend.

- In pgsql/src/tools/msvc/Solution.pm, generate "fake configure
  output" for pg_config, so that external builds like Slony can figure
  out which options were enabled in the build.

- Dave Page's patch to install libpgport.lib as needed by some client

- Dave Page's patch to install headers in the same directory structure
  as Mingw.

- In pgsql/src/backend/port/win32_sema.c, set maximum semaphore count
  to 32767 instead of 1.  Fixes errorcode 298 when unlocking a
  semaphore more than once.  Back-patched to 8.2.  Per report from
  Marcin Waldowski.

- In pgsql/src/tools/msvc/Install.pm, don't try to install uuid-ossp
  since we don't build it.  Per buildfarm member mastodon.

Neil Conway committed:

- Support for MOVE in PL/PgSQL. Initial patch from Magnus, some
  improvements by Pavel Stehule, and reviewed by Neil Conway.

- Add support for IN as alternative to FROM in PL/PgSQL's FETCH
  statement, for consistency with the backend's FETCH command. Patch
  from Pavel Stehule, reviewed by Neil Conway.

- Remove no-longer-true statement from the docs. Since the default
  config now enables row-level stats, the out of the box stats volume
  is no longer particularly low.

- Another tweak for tab completion of CREATE TEMP.  Instead of only
  completing CREATE { TEMP | TEMPORARY } TABLE, we should also suggest
  VIEW and SEQUENCE.  Per Greg Sabino Mullane.

- Consistency tweaks for a table in the SGML docs: we don't terminate
  table entries describing functions with periods.

- Minor enhancement to psql tab completion. If we see "CREATE
  TEMPORARY", we can complete "TABLE". The previous coding only looked
  for "CREATE TEMP".  Note that I didn't add TEMPORARY to the list of
  suggested completions after we've seen "CREATE", since TEMP is
  equivalent and more concise.  But if the user has already manually
  typed TEMPORARY, we may as well complete TABLE for them.

- Minor tweak for DISCARD ref page.

- Rename the newly-added commands for discarding session state.  RESET
  PLANS, and DISCARD TEMP, respectively.  This is to avoid confusion
  with the pre-existing RESET variants: the DISCARD commands are not
  actually similar to RESET.  Patch from Marko Kreen, with some minor

- Minor consistency tweak for SGML docs.

- Fix newly-introduced documentation typo in

- Heikki Linnakangas's patch which fixes LOCK_DEBUG compilation in the
  8.2 branch; HEAD was fixed earlier.

== Rejected Patches (for now) ==

No one was disappointed this week :-)

== Pending Patches ==

Theo Schlossnagle sent in a patch to correct PL/Perl's handling of
bytea input types.

ITAGAKI Takahiro sent in version 4.1 of his Load Distributed
Checkpoint patch.

ITAGAKI Takahiro sent in a patch to fix autovacuum startup.

Gregory Stark sent in another revision of his SORT/LIMIT optimization.

Neil Conway sent in a patch to allow hashing NUMERICs.

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