Comments on: Do Frequent Commits Fix ORA-01555?

By: bharathy

bharathy — Fri, 21 Oct 2011 02:38:09 +0000

hi,
we are getting ORA-01555: snapshot too old: rollback segment number error when we are trying to fetch a data from other database and try to insert in to ours.we are running this as a batch and moreover we are not using any cursors in this

example

delete our_db_table;
begin
insert into our_db_table
(col1,col2,col3)
select col1,col2,col3 from other_db_table;

update db_erro_table;
commit;
end

we think instead of hitting other database everytime , if we use cursor or buffer it will reduce the executing time and get rid of the above error.

kindly suggest

By: Steve

Steve — Sat, 10 Jul 2010 14:13:26 +0000

In regards to Pasi’s post, that is incorrect. UNDO_RETENTION is alive and well in the versions of Oracle used on planet Earth. Old post, but wrong is wrong.

By: rohan

rohan — Thu, 20 May 2010 15:52:57 +0000

i have not understood that if undo_retention is higher as u suggest then obviously it take that much time to hold the undo objects . i think if undo_retention is lower then only it will work fine to insert millions of record.

By: Pasi Parkkonen

Pasi Parkkonen — Tue, 30 Dec 2008 08:08:46 +0000

Please remember that from 10g Release 2 (10.2.x) and above the UNDO_RETENTION – parameter has become obsolete. You do not need to set it anymore since Oracle doesn’t use it.
The size of the actual UNDO tablespace will limit the amount of Undo records held => size the UNDO tablespace properly to hold enough Undo data.

Great site and cool examples!
Pasi Parkkonen

By: Undone by Undo · Steve Karam · The Oracle Alchemist

Undone by Undo · Steve Karam · The Oracle Alchemist — Thu, 12 Jun 2008 16:25:05 +0000

[...] is UNDO. If you do not have enough UNDO to satisfy your long running queries, you may receive an ‘ORA-01555: snapshot too old, rollback segment too small’ [...]

By: dm

dm — Fri, 24 Aug 2007 17:56:40 +0000

I would have different wish for UNDO behavior. Just wondering if you have any opinion â€¦
I am interested in migrating a large database (9i) on a different platform â€“ and I am forced to use export-import (full) technique. I have some tables with few hundreds-millions records and lot of indexes on those tables. Besides other speed tuning techniques for import (e.g. disabling archive log and even the use of _disable_logging=TRUE), I would like to change the behavior of Oracle engine to completely avoid the UNDO generation â€“ I mean, for the duration of import only, I would like to have just the data coming into place, bypassing any unnecessary process like generating UNDO. I am also interested in finding a way of forcing Oracle engine to use a particular amount of PGA and a particular size of SORT_AREA in order to avoid the sorting taking place in TEMP.
â€¦
So, just adding something to this (or to another) topic â€¦

By: steve

steve — Tue, 31 Oct 2006 19:14:28 +0000

I should probably add here that commits should occur at the end of a logical transaction. This means you should not do them based on a modulus-driven commit or other method, but by the business rules.