== PostgreSQL Weekly News - May 06 2007 ==

== PostgreSQL Weekly News - May 06 2007 ==

The first road2pgday talk happened this week.  The page in Italian has
slides.
http://www.pghost.eu/node/9
Below is video.
http://www.youtube.com/profile?user=neothezion

== PostgreSQL Product News ==

DataArchitect 4.0 released.
http://www.thekompany.com/products/dataarchitect/

psqlODBC 08.02.0400 released.
http://psqlodbc.projects.postgresql.org/release.html

pyswarm 0.7.1 released.
http://pyswarm.sourceforge.net/

== PostgreSQL Jobs for May ==

http://archives.postgresql.org/pgsql-jobs/2007-05/threads.php

== PostgreSQL Local ==

Get on the Road to PgDay!
http://www.pgday.it/en/node/95

Registration is open for PGCon 2007
http://www.pgcon.org/2007/registration.php

== PostgreSQL in the News ==

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

General Bits, Archives and occasional new articles:
http://www.varlena.com/GeneralBits/

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 david@fetter.org or in German at pwn@pgug.de by Sunday at 3:00pm
Pacific Time.

== Applied Patches ==

Bruce Momjian committed:

- Update TODO to reflect new direction in plan tracking and
  invalidation.

- Mark TODO as done: "Allow multiple vacuums so large tables do not
  starve small."

- Wording update to FAQ_DEV..

- Add note to FAQ_DEV that regression tests might need to be added.

- In developer's FAQ, update list API, from Tom Lane.

- Add FAQ item about how patches are reviewed.

- Mark TODO as done: "Allow ORDER BY ... LIMIT # to select high/low
  value without sort"

Andrew Dunstan committed:

- Make clearer how arguments and return values in pl/perl are escaped.
  This is to clarify the situation that Theo Schlossnagle recently
  reported on -bugs.

Neil Conway committed:

- Doc tweak: add an xref to pgsql/doc/src/sgml/func.sgml.

- Fix some typos in the documentation.  Patch from Brian Gough.
  Backport the relevant fixes to 8.2 as well.

Alvaro Herrera committed:

- Fix a few more double words in docs.

- Use the new TimestampDifferenceExceeds API instead of
  timestamp_cmp_internal and TimestampDifference, to make coding
  clearer.  I think this should also fix the failure to start workers
  in platforms with low resolution timers, as reported by Itagaki
  Takahiro.

- Fix failure to check for INVALID worker entry in the new autovacuum
  code, which could happen when a worker took to long to start and was
  thus "aborted" by the launcher.  Noticed by lionfish buildfarm
  member.

Magnus Hagander committed:

- In pgsql/src/backend/utils/adt/selfuncs.c, check return code from
  strxfrm on Windows since it has a non-standard way of indicating
  errors, so we don't try to allocate INT_MAX bytes to store a result
  in.  Per ITAGAKI Takahiro.

- Release builds generate different strangely formatted export names
  for local symbols, that shouldn't be exported. This patch excludes
  them, cutting down about 10,000 exported symbols and decreasing the
  binary size by 20%.

- Dave Page's patch which adds a wrapper script install.bat around
  install.pl that calls buildenv.bat before doing the install.

Tom Lane committed:

- Add a line to the EXPLAIN ANALYZE output for a Sort node, showing
  the actual sort strategy and amount of space used.  By popular
  demand.

- Kazuhiro Inaoka's patch which adds tas() support for Renesas' M32R
  processor.

- Suppress a recently-introduced 'variable might be clobbered by
  longjmp' warning.

- A few fixups in error handling: mark pg_re_throw() as noreturn for
  gcc, and for other compilers, insert a dummy exit() call so that
  they understand PG_RE_THROW() doesn't return.  Insert fflush(stderr)
  in ExceptionalCondition, per recent buildfarm evidence that that
  might not happen automatically on some platforms.  And const-ify
  ExceptionalCondition's declaration while at it.

- Teach tuplesort.c about "top N" sorting, in which only the first N
  tuples need be returned.  We keep a heap of the current best N
  tuples and sift-up new tuples into it as we scan the input.  For M
  input tuples this means only about M*log(N) comparisons instead of
  M*log(M), not to mention a lot less workspace when N is small ---
  avoiding spill-to-disk for large M is actually the most attractive
  thing about it.  Patch includes planner and executor support for
  invoking this facility in ORDER BY ... LIMIT queries.  Greg Stark,
  with some editorialization by moi.

- Tweak hash index AM to use the new ReadOrZeroBuffer bufmgr API when
  fetching pages it intends to zero immediately.  Just to show there
  is some use for that function besides WAL recovery :-).  Along the
  way, fold _hash_checkpage and _hash_pageinit calls into _hash_getbuf
  and friends, instead of expecting callers to do that separately.

- Dept. of second thoughts: add comments cautioning against using
  ReadOrZeroBuffer to fetch pages from beyond physical EOF.  This
  would usually work, but would cause problems for md.c if writes
  occurred beyond a segment boundary when the previous segment file
  hadn't been fully extended.

- Heikki Linnakangas's patch which makes the following change:
  During WAL recovery, when reading a page that we intend to overwrite
  completely from the WAL data, don't bother to physically read it;
  just have bufmgr.c return a zeroed-out buffer instead.  This speeds
  recovery significantly, and also avoids unnecessary failures when a
  page-to-be-overwritten has corrupt page headers on disk.  This
  replaces a former kluge that accomplished the latter by pretending
  zero_damaged_pages was always ON during WAL recovery; which was OK
  when the kluge was put in, but is unsafe when restoring a WAL log
  that was written with full_page_writes off.

- Fix things so that when CREATE INDEX CONCURRENTLY sets
  pg_index.indisvalid true at the very end of its processing, the
  update is broadcast via a shared-cache-inval message for the index;
  without this, existing backends that already have relcache entries
  for the index might never see it become valid.  Also, force a
  relcache inval on the index's parent table at the same time, so that
  any cached plans for that table are re-planned; this ensures that
  the newly valid index will be used if appropriate.  Aside from
  making C.I.C. behave more reasonably, this is necessary
  infrastructure for some aspects of the HOT patch.  Pavan Deolasee,
  with a little further stuff from me.

- Fix oversight in PG_RE_THROW processing: it's entirely possible that
  there isn't any place to throw the error to.  If so, we should treat
  the error as FATAL, just as we would have if it'd been thrown
  outside the PG_TRY block to begin with.  Although this is clearly a
  *potential* source of bugs, it is not clear at the moment whether it
  is an *actual* source of bugs; there may not presently be any PG_TRY
  blocks in code that can be reached with no outer longjmp catcher.
  So for the moment I'm going to be conservative and not back-patch
  this.  The change breaks ABI for users of PG_RE_THROW and hence
  might create compatibility problems for loadable modules, so we
  should not put it into released branches without proof that it's
  needed.

- Fix a thinko in my patch of a couple months ago for bug #3116: it
  did the wrong thing when inlining polymorphic SQL functions, because
  it was using the function's declared return type where it should
  have used the actual result type of the current call.  In 8.1 and
  8.2 this causes obvious failures even if you don't have assertions
  turned on; in 8.0 and 7.4 it would only be a problem if the inlined
  expression were used as an input to a function that did run-time
  type determination on its inputs.  Add a regression test, since this
  is evidently an under-tested area.

- Change the timestamps recorded in transaction commit/abort xlog
  records from time_t to TimestampTz representation.  This provides
  full gettimeofday() resolution of the timestamps, which might be
  useful when attempting to do point-in-time recovery --- previously
  it was not possible to specify the stop point with sub-second
  resolution.  But mostly this is to get rid of TimestampTz-to-time_t
  conversion overhead during commit.  Per my proposal of a day or two
  back.

- Fix oversight in my patch of yesterday: forgot to ensure that stats
  would still be forced out at backend exit.

== Rejected Patches (for now) ==

No one was disappointed this week :-)

== Pending Patches ==

Heikki Linnakangas sent an update of Simon's Heap Page Diagnostic
Functions.

Gavin Sherry sent in an update to his bitmap index patch.

Jaime Casanova sent in another revision of his patch which adds a GUC
for temp_tablespaces.

Dany DeBontridder sent in a patch which enables pg_dump to dump
individual objects.

Andrew Dunstan sent in a patch documenting PL/Perl's behavior with
bytea inputs.

Joachim Wieland sent in a patch which addresses the outstanding issues
of the recent guc patch.

Neil Conway sent in a patch which enables integer datetimes by
default.

Pavel Stehule sent in another revision of his patch which adds table
function support per SQL2003: T326 Table Functions.