Re: 7.4beta2 vs 7.3.3

Gaetano Mendola wrote:
> Tom Lane wrote:
> 
>>
>> Hm, it sure looks to be exactly the same plan.  The performance
>> difference seems to be just that the seqscans are faster.  I surmise
>> that in the 7.3 database you had a lot of dead rows, or at least a lot
>> of free space.  Possibly you need to vacuum more often to keep down the
>> amount of junk in the tables.
> 
> 
> The two databases were created from scratch and the first
> operation on it ( after a vacuum analyze ) was just that query.
> 
> I will try to pump up the statistic target.

The default_statistics_target was already 1000 for
postgres7.4beta2 and after setting this value to 1000
for postgres7.3.3 I had the same explain with the same
expected row ( almost 400 ) and the almost the same time execution.


Another piece: The query

SELECT ud.*
FROM user_data ud,     class_default cd
WHERE ud.id_class = cd.id_class AND      cd.id_provider = 39;

( I removed the huge table )

take just few ms to be executed.


Regards
Gaetano Mendola