Thread: Alpha4 Available Now

The fourth alpha release for PostgreSQL version 9.0, 9.0alpha4, is now
available. This alpha contains several new major features added since
the previous alpha. Please download, install, and test it to give us
early feedback on the features being developed for the next version of
PostgreSQL.

Features added in Alpha4 include:

* Streaming Replication for binary log-based replication of PostgreSQL
* New in-memory, high-performance Listen/Notify queue
* Automatic row-count return to drivers on SELECT queries
* ROWS PRECEDING and ROWS FOLLOWING windowing functions

These new major features mean that we need you to participate in testing
them. If you are able to help with organized alpha testing, please see
the Alpha/Beta testing page: http://wiki.postgresql.org/wiki/HowToBetaTest

Alphas are not stable and should never be used in production; they are
for testing new features only. There is no guarantee that any features
or APIs present in the alphas will be present, or the same, in the final
release.  Previous alpha versions were called "8.5"; the 9.0 alpha is
the same version of PostgreSQL, renamed for the release.  Additional
alpha releases, or a beta release, will be available for testing in a
few weeks.

More detail is available in the Release Notes included with each alpha

* Alpha information page: http://www.postgresql.org/developer/alpha
* Download the alpha: http://www.postgresql.org/ftp/source/9.0alpha4

Alpha4 is currently available in source code form only. Binary packages
for some operating systems will be prepared in the coming days.

http://developer.postgresql.org/pgdocs/postgres/release-9-0.html

Performance section:

> Simplify the forms foo <> true and foo <> false to foo = false and 
> foo = true during query optimization.

Will it work correct;ly when foo is NULL?

On Feb 26, 2010, at 0:55 , Дмитрий Фефелов wrote:

> http://developer.postgresql.org/pgdocs/postgres/release-9-0.html
>
> Performance section:
>
>> Simplify the forms foo <> true and foo <> false to foo = false and
>> foo = true during query optimization.
>
> Will it work correct;ly when foo is NULL?

It shouldn't have any effect: NULL <> anything and NULL = anything is
NULL

SELECT arg1, arg2,       (arg1 <> arg2) AS "arg1 <> arg2",       (arg1 = arg2) AS "(arg1 = arg2)"  FROM (VALUES (TRUE,
TRUE),(TRUE, FALSE),               (FALSE, TRUE), (FALSE, FALSE),               (NULL, TRUE), (NULL, FALSE)) AS bools
(arg1,arg2)  ORDER BY arg1, arg2; 
  arg1  | arg2 | arg1 <> arg2 | (arg1 = arg2)
--------+------+--------------+--------------- f      | f    | f            | t f      | t    | t            | f t
|f    | t            | f t      | t    | f            | t (null) | f    | (null)       | (null) (null) | t    | (null)
    | (null) 
(6 rows)

Michael Glaesemann
grzm seespotcode net

>
> On Feb 26, 2010, at 0:55 , Дмитрий Фефелов wrote:
>
> > http://developer.postgresql.org/pgdocs/postgres/release-9-0.html
> >
> > Performance section:
> >
> >> Simplify the forms foo <> true and foo <> false to foo = false and
> >> foo = true during query optimization.
> >
> > Will it work correct;ly when foo is NULL?
>
> It shouldn't have any effect: NULL <> anything and NULL = anything is
> NULL

I already got it, dumb question ;))