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It is an interesting question how Oracle manages the undo for read-only.
I might look at :
ORA-1555 Using Automatic Undo Management - How to troubleshoot [ID 389554.1]
ORA-01555 "Snapshot too old" - Detailed Explanation [ID 40689.1]
It is possible
ORA-01555 Snapshot too old
using target database control file instead of recovery catalog RMAN-00571: =========================================================== RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS =============== RMAN-00571: =========================================================== RMAN-03002: failure of list command at 02/24/2011 14:24:42 ORA-01555: snapshot too old: rollback segment number 20 with name "_SYSSMU20_328 6862503$" too small RMAN-06031: could not translate database keyword
ORA-01555: snapshot too old
h3. Would forget the why and fix the issue
increase size of UNDOTBS1
Edited by: mseberg on Nov 9, 2012 7:21 AM
Thanks for the reply, but these do not speak to why we need undo with a readonly tablespace.
Absolutely no DML changing the data...
The asktom reference below talks about read/write operations as well...
Once a table/tablespace is READONLY, why is UNDO even a part of the discussion?
Using RMAN to export a set of tables with consistency set to default (N).Or Oracle recently changed functionality of rman or you are mixing up things here.
I guess you have question for the data pump forum (or export/import forum) and not the rman forum.
Perhaps, but I think that this question deals with 1) the database itself, and 2) RMAN.
My point in mentioning consistency is to highlight that I was trying to exclude even that as a possible cause. Even though no DML is changing data (readonly tablespace) I am EXPLICITLY telling the db I don't care about that either...
mseberg :Don't you agree that knowing why is important?
Edited by: Vorlon1 on Nov 9, 2012 5:31 AM
Well for the matter of consistency this only counts for consistency between tables in you export set not the data per exported table this still needs to be consistent.
Using RMAN to export a set of tables with consistency set to default (N).Could you show us what exactly you are doing ? The command line ?
An ORA-1555 may also appear against the data dictionary which the export is attempting to read from.
Hemant K Chitale