"kwr2k" <Kanwar.Plaha_at_gmail.com> wrote in message
news:1133734763.039658.176820_at_g14g2000cwa.googlegroups.com...
> Hi guys,
> We have a long-running query (CTAS) that throws up ORA-01555. This is
> the only query running against the database, which is Oracle9i
> (9.2.0.6). Also, automatic undo is turned off on instructions from the
> application vendor. Increasing the rollback tablespace makes this error
> go away although the high water mark does not justify the increase in
> tablespace size.
>
> My question is: What are all the possible causes of this error and what
> can be done in each case?
>
> Thanks.
>
- Other DML activity going on against the
data you are reading for the CTAS.
- Your own session causing delayed block
cleanout on the data you are reading.
In either case, the first step is to check on the
efficiency of the query that the CTAS is running -
the quicker it runs, the less chance there is for
other people to generate excess rollback; the
fewer (redundant) data blocks it visits the less
likely it is to cripple itself with delayed block
cleanout.
--
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html
Cost Based Oracle: Fundamentals
http://www.jlcomp.demon.co.uk/appearances.html
Public Appearances - schedule updated 29th Nov 2005
Received on Mon Dec 05 2005 - 01:25:53 CST
