Re: Slow query against ALL_OBJECTS view

"Tanel Poder" <tanel@@peldik.com> wrote in message news:<3e52b61e$1_1_at_news.estpak.ee>...
> Do what?
>
> I think I just stated that analyzing DD could make your DD queries slow.
>
> I wonder whats the situation in next release...
>
> Tanel.
>

Never analyze data dictionary tables, clusters and indexes. It'll make your database run slow.

>
> > > One common cause for slow DD queries problem is, that you have analyzed
> your
> > > data dictionary?
> > >
> >
> > Never ever do that! Read Oracle documentation first! Data dictionary is
> > never to be analyzed.
> >
> > Use hints to force rule-based optimizer.
> >
> > > Tanel.
> > >
> > > "Shujda" <nlalovic_at_comcast.net> wrote in message
> > > news:D6udndLlqNAsWcyjXTWcoQ_at_comcast.com...
> > > > Hello everyone,
> > > > I have about 700 users in database and about 300,000 rows in
> all_objects
> > > > table/view.
> > > > More then 90% of the objects in the database are the private synonyms.
> The
> > > > average user has about 450 private synonyms.
> > > > When I logon to database, and execute the query:
> > > > SELECT username FROM all_users WHERE EXISTS(SELECT 'X' FROM
> all_objects
> > > > WHERE owner = username), I get the results within 3-4 seconds. When I
> logon
> > > > as someone else, the same query takes forever to execute (more then 30
> > > > minutes). The difference between me and the other user is that I have
> > > > connect, resource and dba roles and he has connect and resource only.
> When
> I
> > > > grant him dba role, the same query gets executed very fast. When I
> revoke
> > > > it, it becomes slow again. I know that all_users is a view and that it
> > > > returns different recordset depending on who is logged on, but I
> didn't
> know
> > > > that it can be such difference in performance...
> > > > The biggest problem is that this query gets generated by SQL Navigator
> when
> > > > you click on "Schemas" node, and I can't tune it up.
> > > > What is the trick? How can I make it run faster.
> > > > Did I hit some limits?
> > > > Thanks.
> > > > Shujda
> > > >
> > > >
> > > >
> > > >
Received on Thu Feb 20 2003 - 10:55:10 CST