PostgreSQL Weekly News [LWN.net]

From:		Robert Treat <xzilla-AT-users.sourceforge.net>
To:		pgsql-announce-AT-postgresql.org
Subject:		[ANNOUNCE] == PostgreSQL Weekly News - July 6th 2004 ==
Date:		Tue, 6 Jul 2004 23:59:22 -0400

== PostgreSQL Weekly News - July 6th 2004 ==

        Having passed the July 1st deadline, we are now officially in feature 
freeze. That means that any patches that introduce new features will be held 
off until the next development cycle. What type of patches will be accepted? 
Bugfixes, clean up of loose ends on new features, and documentation 
improvements are all welcome. The core team is currently targetting July 15th 
for the first official beta release, but we'll keep you posted as development 
progresses.

        Several outstanding patches were committed this week as the 
patch-queue was cleared out. The fuzzymatch module in contrib added double 
metaphone code, and metaphone was changed so that an empty input string 
causes an empty output string to be returned rather than toss an ERROR. 
Operators for interval-plus-datetime were fleshed out for better SQL 
compliance. Two procedural languages received updates this week as well. The 
first involved a changing in the parsing of FOR loops in plpgsql so that the 
integer-loop-vs-query-loop decision is driven off the presence of '..' 
between IN and LOOP, rather than the presence of a matching record/row 
variable name. This means that the general error for mistyped record 
variables will now give a more meaningful error message than one referencing 
'..'. The other involved several upgrades to the plperl module thanks to the 
folks at Command Prompt and several developers who organized themselves on 
www.pgfoundry.org.  New functionality includes shared data and namespace 
support, trigger support, support for returning records, spi_exec 
functionality, and the ability to return "record" and "setof record".

        So what else will be in this next release?  With the caveat that these 
features could be removed during the beta cycle, most of the big name 
features made it in under the wire including nested transactions, PITR, and 
integrated pg_autovacuum. It is also worth reminding folks about win32 
support, tablespace support, and the ARC buffer code, which is making this 
release one of the most significant in several years. Stay tuned as beta 
progress for updates on these features and a complete list of changes due in 
the next version of PostgreSQL.



== PostgreSQL Product News ==
                                                                                
Slony 1.0.0 Released
http://gborg.postgresql.org/project/slony1/news/newsfull.php?news_id=182
                                                                                
shadonet.com introduces free PostgreSQL hosting
http://www.postgresql.org/news/205.html



== PostgreSQL In the News ==
                                                                                
Fujitsu foots the bill for new PostgreSQL database features
http://software.newsforge.com/software/04/07/01/0721222.shtml?tid=72&tid=82
                                                                                
FAQ on when to use "for update" in a query
http://techdocs.postgresql.org/guides/Forupdate
                                                                                
Relational Databases Rule the Roost
http://sdtimes.com/news/105/story15.htm
                                                                                
Connect Computing Gives User a Linux Option
http://www.linuxpr.com/releases/7013.html
                                                                                
Why Write PostgreSQL Extension Functions?
http://www.onlamp.com/pub/a/onlamp/2004/06/28/postgresql_extensions.html



== Upcoming Events ==
                                                                                
OSCon: Portland, OR, USA: July 26-30
There will be a PostgreSQL Track with many community members participating.
http://conferences.oreillynet.com/os2004/
                                                                                
Linux World Expo: San Francisco, CA, USA: August 3-5
PostgreSQL will have a booth and B.O.F with OSDL.



== PostgreSQL Weekly News - July 6th 2004 ==
Don't forget to read Elein Mustain's Weekly Summary of the PostgreSQL
General Mailing List http://www.varlena.com/GeneralBits/
                                                                                
On the Web:
http://www.postgresql.org
http://advocacy.postgresql.org


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Nested Transactions

Posted Jul 7, 2004 23:14 UTC (Wed) by ccyoung (subscriber, #16340) [Link]

Is "nested transactions" the same as "autonomous transactions"? For example, if you are in transaction A and begin transaction B, commit B - will B stay committed even if A is rolled back? Or is it that you can roll back to a certain step in a transaction and proceed from there?

If the former, this is great news for database bigots such as myself. It allows, for example, logging within triggers, great for error logs, recovery, and debugging. It allows more business rules to be at the database level - where they should be, of course.

Nested Transactions

Posted Jul 8, 2004 2:38 UTC (Thu) by alvherre (subscriber, #18730) [Link]

Is "nested transactions" the same as "autonomous transactions"? For example, if you are in transaction A and begin transaction B, commit B - will B stay committed even if A is rolled back? Or is it that you can roll back to a certain step in a transaction and proceed from there?

The latter. The feature is much more like SQL-standard's savepoints than autonomous transactions, as you name them. In fact, there's no way to "commit" a nested transaction; it will be truly committed only when the parent transaction commits.

If the former, this is great news for database bigots such as myself. It allows, for example, logging within triggers, great for error logs, recovery, and debugging. It allows more business rules to be at the database level - where they should be, of course.

You are right, but sadly there are lots of things that are not there yet (and probably they won't be on the upcoming release, because we are now in feature freeze). For example, PL/pgSQL does not at present have support for exceptions --- the function aborts and you can't do anything else from within it. You can retain control of the transaction afterwards if you happened to run the function itself within a nested transaction, but this is less than ideal.

It will undoubtly be better on a future release, and we may yet see exceptions support in PL/pgSQL for the current release, but don't count on it.

Anyway, if you have not been following closely the latest PostgreSQL news, there are a lot of new/better things for this release. One of the things that I'm excited over is the new PL/Perl --- you can now actually do pretty much everything PL/pgSQL can do, including returning sets, writing triggers, and other cool stuff.