== Wöchentlicher PostgreSQL Newsletter - 31. Oktober 2010 ==

Der Originalartikel befindet sich unter:

http://www.postgresql.org/community/weeklynews/pwn20101031



== Wöchentlicher PostgreSQL Newsletter - 31. Oktober 2010 ==

Happy Halloween vom wöchentlichen PostgreSQL Newsletter!

PGDay findet dieses Jahr während der südkalifornischen Linux Auss=
tellung
(SCALE) im LAX Hilton Hotel in Los Angeles, Kalifornien am Freitag dem
25. Februar 2011 statt. Vorträge kannst du unter pgday-submissions AT
googlegroups DOT com einreichen.

Andreas Scherbaum wurde in einem Podcast über PostgreSQL interviewt:
http://andreas.scherbaum.la/blog/archives/743-POFACS-Postgre SQL.html

== PostgreSQL Produkt Neuigkeiten ==

psqlODBC 09.00.0200, ein ODBC Treiber für PostgreSQL, ist erschienen.
http://psqlodbc.projects.postgresql.org/release.html

Postgres-XC 0.9.3, ein Clustering System für PostgreSQL, ist erschiene=
n.
http://postgres-xc.sourceforge.net/

== PostgreSQL Jobs im Oktober ==

http://archives.postgresql.org/pgsql-jobs/2010-10/threads.ph p

== PostgreSQL Lokal ==

Die Deutsche PostgreSQL Anwendergruppe hat einen Stand auf der
OpenRheinRuhr 2010 am 13. und 14. November in Oberhausen,
Deutschland. Andreas Scherbaum hält einen Vortrag über neue
Features in PostgreSQL 9.0.
http://andreas.scherbaum.la/blog/archives/744-PostgreSQL-Ope nRheinRuhr-2010=
..html

Die Deutsche PostgreSQL Anwendergruppe ist mit einem Stand, einem
Vortrag und einem Workshop auf dem Brandenburger Linux-Infotag 2010
in Potsdam, Deutschland am 6. November 2010 präsent.
http://andreas.scherbaum.la/blog/archives/746-PostgreSQL-Bra ndenburger-Linu=
x-Infotag-2010.html

Registrierung für PGDay.EU 2010 vom 6. bis 8. Dezember in
Stuttgart, Deutschland ist jetzt offen.
http://2010.pgday.eu/register

PgDay.IT 2010 wird am 10. Dezember in Rom stattfinden. Der Call for
Papers ist jetzt offen.
http://www.pgday.it/

== PostgreSQL in den News ==

Planet PostgreSQL: http://planet.postgresql.org/

Dieser wöchentliche PostgreSQL Newsletter wurde erstellt von David Fet=
ter.

Sende Neuigkeiten und Ankündigungen bis Sonntag, 15 Uhr Pazifischer
Zeit. Bitte sende englische Beiträge an david@fetter.org, deutsche an
pwn@pgug.de, italienische an pwn@itpug.org, spanische an pwn@arpug.com.ar.

== Reviews ==

== Angewandte Patches ==

Tom Lane pushed:

- Work around rounding misbehavior exposed by buildfarm.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D4ba6=
1a487e39eaf859cd9face9520b30127e6a91

- Fix inline_set_returning_function() to preserve the invalItems list
properly. This avoids a possible crash when inlining a SRF whose
argument list contains a reference to an inline-able user function.
The crash is quite reproducible with CLOBBER_FREED_MEMORY enabled,
but would be less certain in a production build. Problem introduced
in 9.0 by the named-arguments patch, which requires invoking
eval_const_expressions() before we can try to inline a SRF. Per
report from Brendan Jurd.
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http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3Def55=
e294e66725c412d55b9689328235141d816d

- Fix overly-enthusiastic Assert in printing of Param reference
expressions. A NestLoopParam's value can only be a Var or Aggref,
but this isn't the case in general for SubPlan parameters, so
print_parameter_expr had better be prepared to cope. Brain fade in
my recent patch to print the referenced expression instead of just
printing $N for PARAM_EXEC Params. Per report from Pavel Stehule.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3Dc687=
3eac4c33720140240cdbd1a663fecc922c57

- Fix up some oversights in psql's Unicode-escape support. Original
patch failed to include new exclusive states in a switch that needed
to include them; and also was guilty of very fuzzy thinking about
how to handle error cases. Per bug #5729 from Alan Choi.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D35d8=
9401525677441824c6f2116b9f7d0cc3caac

- Previous patch had no detectable virtue other than being a
one-liner. Try to make the code look self-consistent again, so it
doesn't confuse future developers.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3De672=
1c6e1617a0fc8b4bce8eacba8b5a381f1f21

- Fix plpgsql's handling of "simple" expression evaluation. In
general, expression execution state trees aren't re-entrantly
usable, since functions can store private state information in them.
For efficiency reasons, plpgsql tries to cache and reuse state trees
for "simple" expressions. It can get away with that most of the
time, but it can fail if the state tree is dirty from a previous
failed execution (as in an example from Alvaro) or is being used
recursively (as noted by me). Fix by tracking whether a state tree
is in use, and falling back to the "non-simple" code path if so.
This results in a pretty considerable speed hit when the non-simple
path is taken, but the available alternatives seem even more
unpleasant because they add overhead in the simple path. Per idea
from Heikki Linnakangas. Back-patch to all supported branches.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D8ce2=
2dd4c51b6e8155889653c0116cad13877512

- Save a few cycles in plpgsql simple-expression initialization.
Instead of using ExecPrepareExpr, call ExecInitExpr. The net change
here is that we don't apply expression_planner() to the expression
tree. There is no need to do so, because that tree is extracted
from a fully planned plancache entry, so all the needed work is
already done. This reduces the setup costs by about a factor of 2
according to some simple tests. Oversight noted while fooling
around with the simple-expression code for previous fix.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D37e0=
a016547abb3526b685d7aacbd0a4d57f6937

- In psql, make \? output of \dg and \du the same. The previous
wording might have suggested that \du only showed login roles and
\dg only group roles, but that is no longer the case. Proposed by
Josh Kupershmidt.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D2995=
91d1a293e737d72d57aa8545c6c00d19db1d

- In psql, add tab completion for psql \dg and \z. Josh Kupershmidt.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3Da3d4=
0e9fb51f8aab9cde5d5018be5e46332275fd

- Avoid creation of useless EquivalenceClasses during planning.
Zoltan Boszormenyi exhibited a test case in which planning time was
dominated by construction of EquivalenceClasses and PathKeys that
had no actual relevance to the query (and in fact got discarded
immediately). This happened because we generated PathKeys
describing the sort ordering of every index on every table in the
query, and only after that checked to see if the sort ordering was
relevant. The Emmanuel Cecchet/PK construction code is O(N^2) in
the number of ECs, which is all right for the intended number of
such objects, but it gets out of hand if there are ECs for lots of
irrelevant indexes. To fix, twiddle the handling of mergeclauses a
little bit to ensure that every interesting Emmanuel Cecchet is
created before we begin path generation. (This doesn't cost
anything --- in fact I think it's a bit cheaper than before ---
since we always eventually created those ECs anyway.) Then, if an
index column can't be found in any pre-existing Emmanuel Cecchet, we
know that that sort ordering is irrelevant for the query. Instead
of creating a useless Emmanuel Cecchet, we can just not build a
pathkey for the index column in the first place. The index will
still be considered if it's useful for non-order-related reasons,
but we will think of its output as unsorted.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D1423=
1a41a94b2345cc679ff67dbee1bf7dac7029

- Oops, missed one fix for EquivalenceClass rearrangement. Now that
we're expecting a mergeclause's left_ec/right_ec to persist from the
initial assignments, we can't just blithely zero these out when
transforming such a clause in adjust_appendrel_attrs. But really it
should be okay to keep the parent's values, since a child table's
derived Var ought to be equivalent to the parent Var for all
EquivalenceClass purposes. (Indeed, I'm wondering whether we
couldn't find a way to dispense with add_child_rel_equivalences
altogether. But this is wrong in any case.)
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D48a1=
fb23900d73e7d9cb2dc0408c745cd03597a7

- Fix comparisons of pointers with zero to compare with NULL instead.
Per C standard, these are semantically the same thing; but saying
NULL when you mean NULL is good for readability. Marti Raudsepp,
per results of INRIA's Coccinelle.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3Dbfd3=
f37be309c3647844aed937e6a66aad5fd3cb

- Provide hashing support for arrays. The core of this patch is
hash_array() and associated typcache infrastructure, which works
just about exactly like the existing support for array comparison.
In addition I did some work to ensure that the planner won't think
that an array type is hashable unless its element type is hashable,
and similarly for sorting. This includes adding a datatype
parameter to op_hashjoinable and op_mergejoinable, and adding an
explicit "hashable" flag to SortGroupClause. The lack of a
cross-check on the element type was a pre-existing bug in mergejoin
support --- but it didn't matter so much before, because if you
couldn't sort the element type there wasn't any good alternative to
failing anyhow. Now that we have the alternative of hashing the
array type, there are cases where we can avoid a failure by being
picky at the planner stage, so it's time to be picky. The issue of
exactly how to combine the per-element hash values to produce an
array hash is still open for discussion, but the rest of this is
pretty solid, so I'll commit it as-is.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D186c=
bbda8f8dc5e42f68fc7892f206a76d56a20f

- Revert removal of trigger flag from plperl function hash key. As
noted by Jan Urbanski, this flag is in fact needed to ensure that
the function's input/result conversion functions are set up as
expected. Add a regression test to discourage anyone from making
same mistake in future.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D76b1=
2e0af765b2ca2eeddcabdd5e7c22eda164da

Alvaro Herrera pushed:

- find -path is not portable, so use grep -v instead. Per previous
failure of buildfarm member koi (which is no longer failing, alas).
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D9350=
824e708678f6af9657979ba656cf1951b408

Peter Eisentraut pushed:

- Refactor typenameTypeId() Split the old typenameTypeId() into two
functions: A new typenameTypeId() that returns only a type OID, and
typenameTypeIdAndMod() that returns type OID and typmod. This
isolates call sites better that actually care about the typmod.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D3567=
0340f57d78d6ab023b1fb42fd81339f85d4c

- Add missing newlines at end of files.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3Da87d=
21263600a978ff85142c53375ab25eb30bce

- Remove obsolete release-alpha.sgml. This was only used while the
final release notes for 9.0 were being prepared. The alpha release
notes are now in release-9.1.sgml.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D18d6=
437885d2cf50bb16b09676ff054054591290

- Release notes for 9.1alpha2.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3De9eb=
4f401333209139af1acee2cd4251b05e0397

- Remove tabs from SGML.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D2999=
f4ef354a72f00ab0033ed9c0463d89212b99

- Last-minute updates to 9.1alpha2 release notes.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D7116=
5685b265a8e5fdd615485917affdb0e8fa32

- Change version number in release notes to 9.1alpha2
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3Dbd1f=
f9713369c2f54391112b92e0c22ab5c99180

ITAGAKI Takahiro pushed:

- Add .gitignore for contrib/uuid-ossp.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D07ca=
728f699694781ce62eae9e2fa61cd4ffa542

- Fix typos "are are".
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3Dbf76=
ad07fe59affc64f1554d4ff20ddf4d5e8e59

Heikki Linnakangas pushed:

- Before removing backup_label and irrevocably changing pg_control
file, check that WAL file containing the checkpoint redo-location
can be found. This avoids making the cluster irrecoverable if the
redo location is in an earlie WAL file than the checkpoint record.
Report, analysis and patch by Jeff Davis, with small changes by me.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D0c62=
93dd0361a0d3c72c94ced389c509019713a7

- Note explicitly that hash indexes are also not replicated because
they're not WAL-logged. Make the notice about the lack of
WAL-logging more visible by making it a . Also remove the
false statement from hot standby caveats section that hash indexes
are not used during hot standby.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D5c38=
782cc8b3219d43ac2ccaf4254fd590bde758

- Fix long-standing segfault when accept() or one of the calls made
right after accepting a connection fails, and the server is compiled
with GSSAPI support. Report and patch by Alexander V. Chernikov, bug
#5731.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D869a=
f50fcfdd4448b2dc637d905f1afda689741d

- Give a more specific error message if you try to COMMIT, ROLLBACK or
COPY FROM STDIN in PL/pgSQL. We alread did this for dynamic EXECUTE
statements, ie. "EXECUTE 'COMMIT'", but not otherwise.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3Df184=
de351d6a35355aa8f1c1b655c3f6a5087205

Robert Haas pushed:

- Fix dumb typo in SECURITY LABEL error message. Report by Peter
Eisentraut.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D3579=
a94d6acd9374fbc3b45d0be593331ffd414d

- Minor fixups for psql's process_file() function. Avoid closing
stdin, since we didn't open it. Previously multiple inclusions of
stdin would be terminated with a single quit, now a separate quit is
needed for each invocation. Previous behavior also accessed stdin
after it was fclose()d, which is undefined behavior per ANSI C.
Properly restore pset.inputfile, since the caller expects to be able
to free that memory. Marti Raudsepp.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D1fea=
0c05eb4ac4a21d79471b9a7fe96163306b88

- Add a client authentication hook. KaiGai Kohei, with minor cleanup
of the comments by me.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D2070=
9f813601976076a346c0b0f8e92006e3b3fa

- Note that effective_io_concurrency only affects bitmap heap scans.
Josh Kupershmidt.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D5a12=
c808cf223c7a5498217142cc9cb45efe033a

- Reorganize OS-specific details about write caching into a list.
Along the way, clarify that sdparm can be used on Linux as well as
FreeBSD.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D0d5d=
eebe11818a54f79ca66e1a1d41dae0e0b52b

- Revert "Correct WAL space calculation formula in docs." This reverts
commit 915116bc62db2aaec7001bde6610128f4cbd29f9. Per discussion,
the previous formula was in fact correct.
http://archives.postgresql.org/pgsql-docs/2010-10/msg00038.p hp
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D2cae=
0aeb9c61aef48b6de3fb5c4f7785a06bca0b

Andrew Dunstan pushed:

- Allow generic record arguments to plperl functions.
=20
http://git.postgresql.org/gitweb?p=3Dpostgresql.git;a=3Dcomm itdiff;h=3D6c3c=
7b533e4b73bef99996f92da26c7c4124edd3

== Abgelehnte Patches (bis jetzt) ==

No one was disappointed this week :-)

== Eingesandte Patches ==

Shigeru HANADA sent in another revision of the patch to add SQL/MED
with simple wrappers.

ITAGAKI Takahiro sent in two revisions of a patch to add executor
nodes, which will help with, among other things, SQL/MED.

Alvaro Herrera sent in a patch atop the patch to add EXTENSIONs.

David Fetter sent in two revisions of a patch to add tab completion in
psql for views made writeable by triggers.

Dimitri Fontaine sent in another patch for EXTENSIONs.

Zoltan Boszormenyi, Heikki Linnakangas and Tom Lane traded patches to
speed up planning times for queries on tables with large numbers of
partitions.

Alvaro Herrera sent in a patch to add "ALTER TYPE...ADD ELEMENT" to
enums.

Steve Singer sent in a patch to modify TRUNCATE ... RESTART IDENTITY
so that when the transaction rolls back, the restart of the sequence
also rolls back.

Robert Haas sent in a patch to help explain about sdparm's effects on
WAL durability.

Alvaro Herrera sent in a patch to change ALTER TYPE...ENUM... to
include ADD LABEL [BEFORE|AFTER]. The LABEL is new.

Zoltan Boszormenyi sent in a patch for ECPG to get WHERE CURRENT OF to
accept dynamic cursor names.

Heikki Linnakangas sent in a patch to allow tracking the latest
timeline in standby mode.

Marti Raudsepp sent in a patch to change places where pointers were
compared to 0 to compare them to NULL.

Alexander Korotkov sent in a patch to fix the GiST picksplit method
implementation in contrib/cube.

Andres Freund sent in another revision of the patch to cancel IIT
backends.

Marti Raudsepp sent in some more fixes based on Coccinelli runs.

Dimitri Fontaine sent in a patch to add ALTER...SET SCHEMA... to those
object types that don't already have it.

Peter Eisentraut sent in a patch to avoid passing around type OID +
typmod (+ collation) separately all over the place. Instead, there is
a new struct TypeInfo that contains these fields, and only a pointer
is passed around.

Alex Hunsaker sent in a patch to fix another issue with PL/Perl
trigger functions.

Andres Freund sent in a patch to improve the performance of int32- and
int64-to-text conversions by creating a custom converter rather than
using the standard itoa functions.

--
Andreas 'ads' Scherbaum
Deutsche PostgreSQL User Group: http://www.pgug.de/
DPWN: http://andreas.scherbaum.la/blog/categories/18-PWN




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