== PostgreSQL Weekly News - November 07 2010 ==

От: David Fetter
Тема: == PostgreSQL Weekly News - November 07 2010 ==
Дата: ,
Msg-id: 20101108070140.GF11454@fetter.org
(см: обсуждение, исходный текст)
Список: pgsql-announce

== PostgreSQL Weekly News - November 07 2010 ==

PostgreSQL 9.1alpha2 released.  Get it here:
Here's how to test it:

BuildFarm client 4.4 released.  Please join the buildfarm, especially
if you have an unusual hardware/OS/compiler combination.

FOSDEM is one of the biggest Free and Open Source event held annually
in Brussels, Belgium, on February 5-6, 2011, and attended by around
4000 people.  Send in your proposal to fosdem AT postgresql DOT eu.

NYPUG presents Mladen Gogala, who will speak on moving from Oracle to
PostgreSQL Tuesday, November 9.  Details below.

Early bird registration for PGDay.IT, December 10, 2010 in Rome,
Italy, is open and the schedule is online.

== PostgreSQL Product News ==

Npgsql 2.0.11, a .NET data provider for PostgreSQL, released.

== PostgreSQL Jobs for November ==


== PostgreSQL Local ==

PostgreSQL Booth and BOF at Usenix LISA, November 10-11, San Jose CA

The German PostgreSQL User Group is running a booth at OpenRheinRuhr
2010 on november 13rd and 14th in Oberhausen, Germany.  Andreas
Scherbaum is giving a talk about new features in PostgreSQL 9.0.

The German PostgreSQL User Group is present with a booth, a talk and a
workshop at Brandenburger Linux-Infotag 2010 in Potsdam, Germany on
November 6th.

Registration for PGDay.EU 2010 held on December 6-8 in Stuttgart,
Germany is open.

PgDay.IT 2010 will be in Rome this year December 10th.  The Call for
Papers is now open.

PGDay is scheduled at this year's Southern California Linux Exposition
(SCALE) held in the LAX Hilton Hotel in the city of Los Angeles,
California, on Friday February 25th, 2011.  Post your talk submission
to pgday-submissions AT googlegroups DOT com.

== 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 , German language
to , Italian language to .  Spanish language
to .

== Reviews ==

== Applied Patches ==

Heikki Linnakangas pushed:

- Fix corner-case bug in tracking of latest removed WAL segment during
  streaming replication.  We used log/seg 0/0 to indicate that no WAL
  segments have been removed since startup, but 0/0 is a valid value
  for the very first WAL segment after initdb.  To make that
  unambiguous, store (latest removed WAL segment + 1) in the global
  variable.  Per report from Matt Chesler, also reproduced by Greg

- Bootstrap WAL to begin at segment logid=0 logseg=1
  (000000010000000000000001) rather than 0/0, so that we can safely
  use 0/0 as an invalid value.  This is a more future-proof fix for
  the corner-case bug in streaming replication that was fixed
  yesterday.  We had a similar corner-case bug with log/seg 0/0 back
  in February as well.  Avoiding 0/0 as a valid value should prevent
  bugs like that in the future.  Per Tom Lane's idea.  Back-patch to
  9.0.  Since this only affects bootstrapping, it makes no difference
  to existing installations.  We don't need to worry about the bug in
  existing installations, because if you've managed to get past the
  initial base backup already, you won't hit the bug in the future

Tom Lane pushed:

- Avoid using a local FunctionCallInfoData struct in
  ExecMakeFunctionResult and related routines.  We already had a
  redundant FunctionCallInfoData struct in FuncExprState, but were
  using that copy only in set-returning-function cases, to avoid
  keeping function evaluation state in the expression tree for the
  benefit of plpgsql's "simple expression" logic.  But of course that
  didn't work anyway.  Given the recent fixes in plpgsql there is no
  need to have two separate behaviors here.  Getting rid of the local
  FunctionCallInfoData structs should make things a little faster
  (because we don't need to do InitFunctionCallInfoData each time),
  and it also makes for a noticeable reduction in stack space
  consumption during recursive calls.

- Ensure an index that uses a whole-row Var still depends on its
  table.  We failed to record any dependency on the underlying table
  for an index declared like "create index i on t (foo(t.*))".  This
  would create trouble if the table were dropped without previously
  dropping the index.  To fix, simplify some overly-cute code in
  index_create(), accepting the possibility that sometimes the
  whole-table dependency will be redundant.  Also document this hazard
  in dependency.c.  Per report from Kevin Grittner.  In passing,
  prevent a core dump in pg_get_indexdef() if the index's table can't
  be found.  I came across this while experimenting with Kevin's
  example.  Not sure it's a real issue when the catalogs aren't
  corrupt, but might as well be cautious.  Back-patch to all supported

- Fix buffer overrun in pg_upgrade.  Problem reported, and cause
  identified, by Hernan Gonzalez.

- Fix adjust_semi_join to be more cautious about clauseless joins.  It
  was reporting that these were fully indexed (hence cheap), when of
  course they're the exact opposite of that.  I'm not certain if the
  case would arise in practice, since a clauseless semijoin is hard to
  produce in SQL, but if it did happen we'd make some dumb decisions.

- Use only one hash entry for all instances of a pltcl trigger
  function.  Like plperl and unlike plpgsql, there isn't any cached
  state that could depend on exactly which relation the trigger is
  being fired for.  So we can use just one hash entry for all
  relations, which might save a little something.  Alex Hunsaker.

- Reduce recursion depth in recently-added regression test.  Some
  buildfarm members fail the test with the original depth of 10
  levels, apparently because they are running at the minimum
  max_stack_depth setting of 100kB and using ~ 10k per recursion
  level.  While it might be interesting to try to figure out why
  they're eating so much stack, it isn't likely that any fix for that
  would be back-patchable.  So just change the test to recurse only 5
  levels.  The extra levels don't prove anything correctness-wise

- Reimplement planner's handling of MIN/MAX aggregate optimization.
  Per my recent proposal, get rid of all the direct inspection of
  indexes and manual generation of paths in planagg.c.  Instead, set
  up EquivalenceClasses for the aggregate argument expressions, and
  let the regular path generation logic deal with creating paths that
  can satisfy those sort orders.  This makes planagg.c a bit more
  visible to the rest of the planner than it was originally, but the
  approach is basically a lot cleaner than before.  A major advantage
  of doing it this way is that we get MIN/MAX optimization on
  inheritance trees (using MergeAppend of indexscans) practically for
  free, whereas in the old way we'd have had to add a whole lot more
  duplicative logic.  One small disadvantage of this approach is that
  MIN/MAX aggregates can no longer exploit partial indexes having an
  "x IS NOT NULL" predicate, unless that restriction or something that
  implies it is specified in the query.  The previous implementation
  was able to use the added "x IS NOT NULL" condition as an extra
  predicate proof condition, but in this version we rely entirely on
  indexes that are considered usable by the main planning process.
  That seems a fair tradeoff for the simplicity and functionality

- Use appendStringInfoString() where appropriate in elog.c.  The
  nominally equivalent call appendStringInfo(buf, "%s", str) can be
  significantly slower when str is large.  In particular, the former
  usage in EVALUATE_MESSAGE led to O(N^2) behavior when collecting a
  large number of context lines, as I found out while testing
  recursive functions.  The other changes are just neatnik-ism and
  seem unlikely to save anything meaningful, but a cycle shaved is a
  cycle earned.

- Allow moddatetime's target column to be of type timestamptz.  Dirk

- Include the current value of max_stack_depth in stack depth
  complaints.  I'm mainly interested in finding out what it is on
  buildfarm machines, but including the active value in the message
  seems like good practice in any case.  Add the info to the HINT, not
  the ERROR string, so as not to change the regression tests' expected

- Make get_stack_depth_rlimit() handle RLIM_INFINITY more sanely.
  Rather than considering this result as meaning "unknown", report
  LONG_MAX.  This won't change what superusers can set max_stack_depth
  to, but it will cause InitializeGUCOptions() to set the built-in
  default to 2MB not 100kB.  The latter seems like a fairly
  unreasonable interpretation of "infinity".  Per my investigation of
  odd buildfarm results as well as an old complaint from Heikki.
  Since this should persuade all the buildfarm animals to use a
  reasonable stack depth setting during "make check", revert previous
  patch that dumbed down a recursive regression test to only 5 levels.

- Add support for detecting register-stack overrun on IA64.  Per
  recent investigation, the register stack can grow faster than the
  regular stack depending on compiler and choice of options.  To avoid
  crashes we must check both stacks in check_stack_depth().
  Back-patch to all supported versions.

- Implement an "S" option for psql's \dn command.  \dn without "S" now
  hides all pg_XXX schemas as well as information_schema.  Thus, in a
  bare database you'll only see "public".  ("public" is considered a
  user schema, not a system schema, mainly because it's droppable.)
  Per discussion back in late September.

- Prevent invoking I/O conversion casts via functional/attribute
  notation.  PG 8.4 added a built-in feature for casting
  pretty much any data type to string types (text, varchar, etc).  We
  allowed this to work in any of the historically-allowed syntaxes:
  CAST(x AS text), x::text, text(x), or x.text.  However, multiple
  complaints have shown that it's too easy to invoke such casts
  unintentionally in the latter two styles, particularly field
  selection.  To cure the problem with the narrowest possible change
  of behavior, disallow use of I/O conversion casts from composite
  types to string types via functional/attribute syntax.  The new
  functionality is still available via cast syntax.  In passing,
  document the equivalence of functional and attribute syntax in a
  more visible place.

Michael Meskes pushed:

- Some cleanup in ecpg code: Use bool as type for booleans instead of
  int.  Do not implicitely cast size_t to int.  Make the compiler stop
  complaining about unused variables by adding an empty statement.

Peter Eisentraut pushed:

- Print a make warning when using GNU make older than 3.80.  A
  proposed patch will require GNU make 3.80 or newer.  We will let
  this patch run for a while to see how much damage that would do to
  the buildfarm.

== Rejected Patches (for now) ==

No one was disappointed this week :-)

== Pending Patches ==

Andres Freund sent in two more patches to make COPY more efficient by
creating and using custom integer-to-string conversion routines.

Alex Hunsaker sent in two patches to fix the way PL/Tcl handles
trigger functions analogous to the fix for PL/Perl.

Hitoshi Harada sent in a patch to change sort states to plan states in
some parts of the explain and the executor.

Dimitri Fontaine and Alvaro Herrera traded several revisions of the
patch to add ALTER OBJECT ... SET SCHEMA for the objects where this is
not already doable.

Dimitri Fontaine sent a patch to add execute_from_file().

Peter Eisentraut sent in a patch intended to improve support for
parallel make.

Dimitri Fontaine sent in a patch to add pg_dump support for

Alex Hunsaker sent in a patch to fix the way PL/Python handles trigger
functions similar to how he fixed PL/Perl and PL/Tcl.

ITAGAKI Takahiro sent in a patch to change boolean==true to boolean in
the source code.

Alexander Korotkov and Yeb Havinga traded patches to fix the picksplit
function in the seg contrib module.

KaiGai Kohei sent in a contrib module to allow delaying auth.

Fujii Masao sent in a patch to allow tracking the most recently
replayed transaction.

Marti Raudsepp sent in a patch to revert wal_sync_method to fdatasync
on Linux 2.6.33 or higher because the setting changed as of that

Alvaro Herrera sent in a patch to better document the now-less-dusty

Hitoshi Harada sent in a patch to allow sharing the result data of a
separate plan in a single execution.  This is infrastructure for
writeable CTEs.

Tom Lane sent in a patch to fix an issue with how UNION ALL was

Gurjeet Singh sent in a patch to allow ALTER TABLE to point to a
UNIQUE index which would then become a constraint, for example, a
PRIMARY KEY constraint.

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