Re: performace question...

On Tue, 13 Apr 2004 09:45:29 -0500, Vince Laurent <eAddict_at_yahoo.com> wrote:

>Quick question: Are full table scans bad for performance? I am
>guessing yes. I ran this script:
>
>set serverout on size 1000000
>set verify off
>
>col object_name form a30
>
>PROMPT Column flag in x$bh table is set to value 0x80000, when
>PROMPT block was read by a sequential scan.
>
>spool bufferts.lst
>
>SELECT o.object_name,o.object_type,o.owner
>FROM dba_objects o,x$bh x
>WHERE x.obj=o.object_id
>AND o.object_type='TABLE'
>AND standard.bitand(x.flag,524288)>0
>AND o.owner<>'SYS';
>
>spool off
>
>and the result on one of our DB was 5600! Since Sunday's backup! How
>can I tell the vendor that thier appliction, um, er... works harder
>than it needs to?
>
>Thanks
>
>--------------------------------------
>Come race with us!
>www.mgpmrc.org

How long is a piece of string?

Given these two queries:

SELECT country_name
FROM north_american_countries
WHERE country_code = 'USA';

SELECT customer_name
FROM all_usa_telephone_customers
WHERE telephone_number = '555-5555';

With no more information available -- assuming the two tables are of a structure and size one would expect from their names -- I'd guess that a FTS might actually be the preferred acces for the first query. The second query might be a bit 'performance challenged' if it were forced to use a FTS.

Gi Received on Tue Apr 13 2004 - 12:41:43 CDT