Nouvelles hebdomadaires de PostgreSQL - 5 avril 2009

Les inscriptions sont à présent ouvertes pour le pgCon à Ottawa : http://www.pgcon.org/2009/registration.php

Ouverture des inscriptions pour l'OSCON également. Il y aura un pgDay la veille, soit dimanche : https://en.oreilly.com/oscon2009/public/register

Le PgDay de Florianopolis aura lieu le 22 mai. Contactez Dickson S. Guedes (guedes AROBASE guedesoft DOT net) pour participer ou proposer une conférence : http://www.postgresql.org.br/eventos/pgday/sc

Les nouveautés des produits dérivés

• Archiveopteryx 3.0.7 et 3.1.0, un gestionnaire d'e-mail basé sur PostgreSQL : http://www.archiveopteryx.org/3.0.7, http://www.archiveopteryx.org/3.1.0
• PGORM 0.09, un corrélateur objet-relationnel .NET pour PostgreSQL : http://pgorm.googlecode.com
• PostgreDAC ver. 2.5.1 : http://microolap.com/products/connectivity/postgresdac/download/

PostgreSQL 8.4 Feature of the Week

CIText : David Wheeler a ajouté un nouveau module à "contrib" qui implémente, avec toutes les options, un type de données textes insensibles à la casse.

L'astuce de la semaine

\h <COMMAND> dans psql vous fournira une documentation complète sur un grand éventail de commandes SQL.

(lien vers l'article original)

Offres d'emplois autour de PostgreSQL en April

• http://archives.postgresql.org/pgsql-jobs/2009-04/threads.php

PostgreSQL Local

• Kevin Kempter fera une présentation des sauvegardes et des récupérations lors de la première réunion du PUG de Denver, le 8 avril 2009 : http://www.diapug.org/Meeting.html
• Le PgDay de Brasilia aura lieu le 17 avril. Contactez [fernando.ike (a) gmail (point) com] ou [eduardo (a) planejamento (point) gov (point) br] pour participer : http://www.postgresql.org.br/drupal6/eventos/pgday/df
• La "Percona Performance Conference" prendra place au "Santa Clara Convention Center", Santa Clara, Californie : http://conferences.percona.com/
• L'appel aux conférences est lancé pour le PgDay de São Paulo, programmé le 24 avril. Contactez [marins (point) consultoria (a) gmail (point) com] ou [marcelojscosta (a) gmail (point) com] pour participer.
• "PostgreSQL Conference, U.S. (JDCon)" organise un PgDay lors de la "LinuxFest Northwest" (25 & 26 avril). L'appel aux conférences est consultable à l'adresse : http://www.postgresqlconference.org/
• Il y aura également des PgDays les 29 et 30 avril, respectivement à Porto Velho (RO) et Ji-Parana (RO). Contactez Luis Fernando Bueno : [proflfbueno (a) gmail (point) com] pour participer.
• Michael Renner animera un atelier sur la réplication PostgreSQL lors des "Netways OSDC", les 29 et 30 avril 2009, à Nuremberg (All.) : http://www.netways.de/english/osdc/y2009/programm/w/michael_renner_postgresql_repliziert_ein_ueberblick/
• La PGCon 2009 se tiendra à l'Université d'Ottawa les 21 et 22 mai 2009. Elle sera précédée de deux jours de tutoriels les 19 & 20 mai : http://www.pgcon.org/2009/
• Notez la date : pgDay San Jose, dimanche 19 juillet juste avant l'OSCON. Appel à conférenciers, plus d'infos sous peu !
• La "PGCon Brazil" prendra place à l'Unicamp de Campinas (État de São Paulo) les 23 & 24 octobre 2009.

PostgreSQL dans les média

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

PostgreSQL Weekly News / les nouvelles hebdomadaires vous sont offertes cette semaine par David Fetter et Josh Berkus. La traduction en est assurée par l'équipe PostgreSQLFr.

Proposez vos articles ou annonces avant dimanche 15:00 (heure du Pacifique). Merci de les envoyer en anglais à david (a) fetter.org, en allemand à pwn (a) pgug.de, en italien à pwn (a) itpug.org.

Correctifs appliqués

Tom Lane a commité :

• Fix an oversight in the support for storing/retrieving "minimal tuples" in TupleTableSlots. We have functions for retrieving a minimal tuple from a slot after storing a regular tuple in it, or vice versa; but these were implemented by converting the internal storage from one format to the other. The problem with that is it invalidates any pass-by-reference Datums that were already fetched from the slot, since they'll be pointing into the just-freed version of the tuple. The known problem cases involve fetching both a whole-row variable and a pass-by-reference value from a slot that is fed from a tuplestore or tuplesort object. The added regression tests illustrate some simple cases, but there may be other failure scenarios traceable to the same bug. Note that the added tests probably only fail on unpatched code if it's built with --enable-cassert; otherwise the bug leads to fetching from freed memory, which will not have been overwritten without additional conditions. Fix by allowing a slot to contain both formats simultaneously; which turns out not to complicate the logic much at all, if anything it seems less contorted than before. Back-patch to 8.2, where minimal tuples were introduced.
• In pgsql/src/backend/optimizer/plan/planner.c, fix window function plan generation to cope with volatile sort expressions. (Not clear how useful these really are, but failing is no good...) Per report from David Fetter and Robert Treat.
• Add PQinitOpenSSL() function to support applications that use libcrypto but not OpenSSL (or perhaps vice versa, if that's possible). Andrew Chernow, with minor editorialization by me.
• Add a "relistemp" boolean column to pg_class, which is true for temporary relations (including a temp table's indexes and toast table/index), and false for normal relations. For ease of checking, this commit just adds the column and fills it correctly --- revising the relation access machinery to use it will come separately.
• Modify the relcache to record the temp status of both local and nonlocal temp relations; this is no more expensive than before, now that we have pg_class.relistemp. Insert tests into bufmgr.c to prevent attempting to fetch pages from nonlocal temp relations. This provides a low-level defense against bugs-of-omission allowing temp pages to be loaded into shared buffers, as in the contrib/pgstattuple problem reported by Stuart Bishop. While at it, tweak a bunch of places to use new relcache tests (instead of expensive probes into pg_namespace) to detect local or nonlocal temp tables.
• Fix contrib/pgstattuple and contrib/pageinspect to prevent attempts to read temporary tables of other sessions; that is unsafe because of the way our buffer management works. Per report from Stuart Bishop. This is redundant with the bufmgr.c checks in HEAD, but not at all redundant in the back branches.
• Remove last references to the crypt auth method, per Andreas 'ads' Scherbaum.
• In pgsql/doc/src/sgml/func.sgml, index some array functions, per Mario Splivalo.
• In pgsql/src/bin/pg_dump/pg_dump.c, improve pg_dump's query for retrieving BLOB comments to be more efficient when there are many blobs and not so many comments. Tamas Vincze.
• In pgsql/src/pl/plpgsql/src/pl_exec.c, plpgsql's exec_simple_cast_value() mistakenly supposed that it could bypass casting effort whenever the input value was NULL. However this prevents application of not-null domain constraints in the cases that use this function, as illustrated in bug #4741. Since this function isn't meant for use in performance-critical paths anyway, this certainly seems like another case of "premature optimization is the root of all evil". Back-patch as far as 8.2; older versions made no effort to enforce domain constraints here anyway.
• In pgsql/src/backend/utils/misc/guc.c, fix GUC's reports of assign_hook failure to always include the parameter value we failed to assign, even in "can't happen" cases. Motivated by wondering what's going on in a recent trouble report where "failed to commit" did happen.
• Fix SetClientEncoding() to maintain a cache of previously selected encoding conversion functions. This allows transaction rollback to revert to a previous client_encoding setting without doing fresh catalog lookups. I believe that this explains and fixes the recent report of "failed to commit client_encoding" failures. This bug is present in 8.3.x, but it doesn't seem prudent to back-patch the fix, at least not till it's had some time for field testing in HEAD. In passing, remove SetDefaultClientEncoding(), which was used nowhere.
• In pgsql/src/pl/plpgsql/src/pl_exec.c, minor code beautification/consolidation.
• Refactor ExecProject and associated routines so that fast-path code is used for simple Var targetlist entries all the time, even when there are other entries that are not simple Vars. Also, ensure that we prefetch attributes (with slot_getsomeattrs) for all Vars in the targetlist, even those buried within expressions. In combination these changes seem to significantly reduce the runtime for cases where tlists are mostly but not exclusively Vars. Per my proposal of yesterday.
• Defend against possible crash if a plpython function does not specify names for its arguments. Also add a regression test, since someone apparently changed every single plpython test case to use only named parameters; else we'd have noticed this sooner. Euler Taveira de Oliveira, per a report from Alvaro Herrera.
• In pgsql/src/backend/storage/buffer/bufmgr.c, add a comment documenting the question of whether PrefetchBuffer should try to protect an already-existing buffer from being evicted. This was left as an open issue when the posix_fadvise patch was committed. I'm not sure there's any evidence to justify more work in this area, but we should have some record about it in the source code.
• In pgsql/src/port/path.c, use (unsigned char) cast in argument of pg_tolower(). Maybe it works on Windows without that, but we shouldn't put bad examples where people might copy them. Also, reformat slightly to improve the odds that pgindent won't go nuts on this.
• In pgsql/src/bin/psql/help.c, add missing help output for \ef option. Andrew (RhodiumToad) Gierth.
• In pgsql/doc/src/sgml/ref/psql-ref.sgml, minor wordsmithing on descriptions of some \d commands.
• In pgsql/src/bin/psql/describe.c, make \dt \di and friends more consistent about the treatment of TOAST tables and indexes; to wit, never show either. (You can examine them with plain \d if you're really so inclined.)
• In pgsql/src/bin/psql/describe.c, improve obsolete comment.
• Rewrite interval_hash() so that the hashcodes are equal for values that interval_eq() considers equal. I'm not sure how that fundamental requirement escaped us through multiple revisions of this hash function, but there it is; it's been wrong since interval_hash was first written for PG 7.1. Per bug #4748 from Roman Kononov. Backpatch to all supported releases. This patch changes the contents of hash indexes for interval columns. That's no particular problem for PG 8.4, since we've broken on-disk compatibility of hash indexes already; but it will require a migration warning note in the next minor releases of all existing branches: "if you have any hash indexes on columns of type interval, REINDEX them after updating".
• A session that does not have any live snapshots does not have to be waited for when we are waiting for old snapshots to go away during a concurrent index build. In particular, this rule lets us avoid waiting for idle-in-transaction sessions. This logic could be improved further if we had some way to wake up when the session we are currently waiting for goes idle-in-transaction. However that would be a significantly more complex/invasive patch, so it'll have to wait for some other day. Simon Riggs, with some improvements by Tom.
• Remove the recently added node types ReloptElem and OptionDefElem in favor of adding optional namespace and action fields to DefElem. Having three node types that do essentially the same thing bloats the code and leads to errors of confusion, such as in yesterday's bug report from Khee Chin.
• Make an attempt at fixing our current Solaris 11 breakage: add a configure probe for opterr (exactly like the one for optreset) and have getopt.c define the variables only if configure doesn't find them in libc.
• In pgsql/src/port/getopt.c, hmm, baiji thinks we need explicit 'extern' here.
• Remove contrib/intarray's definitions of the <@ and @> operators, so that they don't cause confusion with the built-in anyarray versions of those operators. Adjust the module's index opclasses to support the built-in operators in place of the private ones. The private implementations are still available under their historical names @ and ~, so no functionality is lost. Some quick testing suggests that they offer no real benefit over the core operators, however. Per a complaint from Rusty Conover.
• In pgsql/src/include/pg_config.h.win32, I had always wondered why pg_config.h.win32 claimed that Windows provides optreset. Current mastodon results prove that in fact it does not; it was only because getopt.c defined the variable anyway that things failed to fall over.
• Remove a boatload of useless definitions of 'int optreset'. If we are using our own ports of getopt or getopt_long, those will define the variable for themselves; and if not, we don't need these, because we never touch the variable anyway.
• Change EXPLAIN output so that subplans and initplans (particularly CTEs) are individually labeled, rather than just grouped under an "InitPlan" or "SubPlan" heading. This in turn makes it possible for decompilation of a subplan reference to usefully identify which subplan it's referencing. I also made InitPlans identify which parameter symbol(s) they compute, so that references to those parameters elsewhere in the plan tree can be connected to the initplan that will be executed. Per a gripe from Robert Haas about EXPLAIN output of a WITH query being inadequate, plus some longstanding pet peeves of my own.
• In pgsql/src/backend/executor/execQual.c, make ExecInitExpr build the list of SubPlans found in a plan tree in order of discovery, rather than reverse order. This doesn't matter functionally (I suppose the previous coding dates from the time when lcons was markedly cheaper than lappend). However now that EXPLAIN is labeling subplans with IDs that are based on order of creation, this may help produce a slightly less surprising printout.
• Change cardinality() into a C-code function, instead of a SQL-language alias for array_length(v,1). The efficiency gain here is doubtless negligible --- what I'm interested in is making sure that if we have second thoughts about the definition, we will not have to force a post-beta initdb to change the implementation.

Alvaro Herrera a commité :

• In pgsql/doc/src/sgml/plpython.sgml, update URL to Python bug tracker. Backpatch to 8.3; doesn't seem worthy of further backpatch.
• Disallow setting fillfactor for TOAST tables. To implement this without almost duplicating the reloption table, treat relopt_kind as a bitmask instead of an integer value. This decreases the range of allowed values, but it's not clear that there's need for that much values anyway. This patch also makes heap_reloptions explicitly a no-op for relation kinds other than heap and TOAST tables. Patch by ITAGAKI Takahiro with minor edits from me. (In particular I removed the bit about adding relation kind to an error message, which I intend to commit separately.)

Bruce Momjian a commité :

• In pgsql/doc/src/sgml/release.sgml, reorder release note sections.
• In pgsql/doc/src/sgml/release.sgml, more release note wording improvements; section order adjustments.
• In pgsql/doc/src/sgml/release.sgml, more release note adjustments, reordering.
• In pgsql/doc/src/sgml/release.sgml, more release note changes, including a lower level of subsections.
• In pgsql/doc/src/sgml/release.sgml, more new subsections in release notes.
• In pgsql/doc/src/sgml/release.sgml, update release note introductory description.
• In pgsql/doc/src/sgml/release.sgml, remove some "Other" sections in the release notes by putting the items at the top of their sections.
• Change psql \d* display so 'S' _or_ a pattern include system objects.
• In pgsql/src/bin/psql/describe.c, do not show information_schema in \d* commands, unless 'S' or pattern is specified. Martin Pihlak.
• Add support for additional DTrace probes. Robert Lor.
• Have PL/pgSQL FETCH set DIAGNOSTICS ROW_COUNT. Andrew (RhodiumToad) Gierth.
• In pgsql/src/backend/utils/misc/guc.c, give a better error message when trying to change "effective_io_concurrency" on systems without posix_fadvise().
• Revert DTrace patch from Robert Lor.
• In pgsql/doc/src/sgml/config.sgml, document that Solaris can't use effective_io_concurrency because of an ineffective posix_fadvise().

Heikki Linnakangas a commité :

• In pgsql/src/backend/storage/ipc/procarray.c, fix a rare race condition when commit_siblings > 0 and a transaction commits at the same instant as a new backend is spawned. Since CountActiveBackends() doesn't hold ProcArrayLock, it needs to be prepared for the case that a pointer at the end of the proc array is still NULL even though numProcs says it should be valid, since it doesn't hold ProcArrayLock. Backpatch to 8.1. 8.0 and earlier had this right, but it was broken in the split of PGPROC and sinval shared memory arrays. Per report and proposal by Marko Kreen.
• In pgsql/src/backend/utils/adt/pg_locale.c, update comment to reflect that LC_COLLATE and LC_CTYPE are now per-database settings.

Magnus Hagander a commité :

• In pgsql/src/bin/initdb/initdb.c, don't crash initdb when we fail to get the current username. Give an error message and exit instead, like we do elsewhere... Per report from Wez Furlong and Robert Treat.
• In pgsql/src/port/path.c, make directory name comparisons on Win32 case insensitive. This method will not catch all different ways since the locale handling in NTFS doesn't provide an easy way to do that, but it will hopefully solve the most common cases causing startup problems when the backend is found in the system PATH. Attempts to fix bug #4694.

Teodor Sigaev a commité :

• In pgsql/contrib/hstore/hstore_io.c, fix memory allocation for output of hstore type. Per report from Zhang Maosen.
• Fix infinite loop while checking of partial match in pending list. Improve comments. Now GIN-indexable operators should be strict. Per Tom Lane's questions/suggestions.

Correctifs rejetés (à ce jour)

• Hitoshi Harada's doc patch which changed HeapTupleSatisfiesNow to HeapTupleSatisfiesVisibility in doc/src/sgml/pgstattuple.sgml.

Correctifs en attente

• Abhijit Menon-Sen sent in a patch to implement has_sequence_privilege().
• Andrew (RhodiumToad) Gierth sent in a patch to psql which adds a mention of \ef to the \? command's output.
• K. Srinath sent in a patch which allows an index to cover all tables in an inheritance hierarchy.
• Pavel Stehule and Tom Lane sent in a couple of versions of a patch to allow raising an exception from _PG_init per previous discussion.
• Heikki Linnakangas sent in a patch to help with message encoding.
• Pavel Stehule sent in a patch to transform array inputs in variadic functions into standard parameters.
• Teodor Sigaev sent in two patches intended to fix a bug in GiST reported by Andrew (RhodiumToad) Gierth.
• Fujii Masao sent in another revision of his pg_standby trigger patch.
• Robert Haas sent in a patch to add SET NDISTINCT to ALTER COLUMN.
• Bruce Momjian sent in another revision of his patch to handle platforms which don't support effective_io_concurrency.
• Martin Pihlak sent in a patch which adds a U (user) modifier to psql's \d commands in order to be able to match patterns only on non-system objects.
• Alvaro Herrera sent in a patch to fix a reloptions bug reported by Khee Chin.
• Teodor Sigaev sent in a patch to fix a crash in GiST insertion of pathological box data.
• Zdenek Kotala sent in another patch to fix the misbehavior of Solaris's getopt.