RE: ORA-01555 Mystery (Help)

Delayed block cleanouts can still cause the ORA-1555, even after locking the table in exlusive mode.

That's the purpose of the analyze, to force the block cleanouts.

Jared

Paul Baumgartel <treegarden_at_YAHOO.COM>
Sent by: root_at_fatcity.com
01/25/02 09:30 AM
Please respond to ORACLE-L  

        To:     Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
        cc: 
        Subject:        RE: ORA-01555 Mystery (Help)

Sure, but the original post concerns a *query*, not a transaction, and before running the query, the user locked the queried table in exclusive mode, to ensure that no other session could write to the queried table. How do we account for the query's need to read from rollback?

• "Baker, Barbara" <bbaker_at_denvernewspaperagency.com> wrote:
  >
  > I have a batch job that does this consistently. It's the only job in
  > the
  > database; it sets the transaction to a hugh rollback segment. And it
  > eats
  > its own tail.
  >
  > Depending on how the job is written, it may need a read consistent
  > view
  > itself (as opposed to some other query in the database needing that
  > read
  > consistent view.) In that case, it may well go try to read its own
  > rollback segment, only to find that it's been overwritten. (Oddly
  > enough,
  > even when there's plenty of space to extend the rollback, Oracle will
  > decide
  > to overwrite the original rollback segments rather than extend if it
  > thinks
  > it doesn't need those segments any more.)
  >
  > I'd strongly suggest you get the stuff from Steve Adams' ixora site
  > that
  > places an uncommitted transaction in your rollback segments for the
  > length
  > of the run. This will guarantee that the rollback segments don't
  > get
  > overwritten.
  > Good luck!
  >
  > Barb
  >
  > > ----------
  > > From: Walter K[SMTP:alden14004_at_yahoo.com]
  > > Reply To: ORACLE-L_at_fatcity.com
  > > Sent: Friday, January 25, 2002 9:15 AM
  > > To: Multiple recipients of list ORACLE-L
  > > Subject: ORA-01555 Mystery (Help)
  > >
  > > Hi,
  > >
  > > A user in our data warehousing group is running into
  > > the old ORA-01555 (snapshot too old) error every time
  > > she runs a massive (20 million rows) select against
  > > one table via a view. I confirmed that the view only
  > > translates to the one table.
  > >
  > > The user swears that no one would be making any
  > > updates/deletes to the table she is selecting from. I
  > > suggested she lock the table in exclusive mode, prior
  > > to running her massive select to guarantee no one else
  > > could change the data in the table and cause the
  > > triggering of the 1555 error. Locking the table was a
  > > viable option because it's a staging table in the
  > > warehouse itself. She locked the table in exclusive
  > > mode last night and it locked; fired off her query,
  > > and it failed 5 hours later with the 1555 error again.
  > >
  > > I'm stumped on this. I just don't see how this is
  > > possible. Any suggestions?
  > >
  > > Thanks!!!
  > > -w
  > >
  > > __________________________________________________
  .

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