Обсуждение: About System Catalogs

Hi gurus,
i have two questions for you.

1) I would like to know if the system catalogs tables are created
     for each database of Postgresql instance or belong to a specific db, such as template0 i suppose.

2) As i had a very large pg_largeogject, i deleted rows e now i have a clean, small table.
    The table is empty but its index  pg_largeogject_loid_pn_index  lasts to retain a lot of bytes.
     How can i do?
     I have to drop and recreate the index?

Thank you very much.

Francesco.Borgoglio@cedacri.it writes:
> 2) As i had a very large pg_largeogject, i deleted rows e now i have a
> clean, small table.
>     The table is empty but its index  pg_largeogject_loid_pn_index  lasts
> to retain a lot of bytes.

REINDEX should fix this.

            regards, tom lane

Tom Lane wrote:

Francesco.Borgoglio@cedacri.it writes: 

2) As i had a very large pg_largeogject, i deleted rows e now i have a 
clean, small table.   The table is empty but its index  pg_largeogject_loid_pn_index  lasts 
to retain a lot of bytes.   

REINDEX should fix this.
 

Is REINDEX still going to be a necessity in the 8.0 release?  I remembered at there was a discussion on the mailing list about a fix or need to fix VACUUM so that manually reindexing would not be necessary...

Thomas Swan wrote:
> Tom Lane wrote:
>
>>Francesco.Borgoglio@cedacri.it writes:
>>
>>
>>>2) As i had a very large pg_largeogject, i deleted rows e now i have a
>>>clean, small table.
>>>    The table is empty but its index  pg_largeogject_loid_pn_index  lasts
>>>to retain a lot of bytes.
>>>
>>>
>>
>>REINDEX should fix this.
>>
>>
>>
> Is REINDEX still going to be a necessity in the 8.0 release?  I
> remembered at there was a discussion on the mailing list about a fix or
> need to fix VACUUM so that manually reindexing would not be necessary...
>

This is already true for the 7.4, I don't remember that vacuum was improved
int that direction in the 8.0.



Regards
Gaetano Mendola