Jack,
You might have a look at the undo advisers, either at the command line or
in Enterprise Manager, where the charts may help explain how you're running
out of undo space.
https://www.morganslibrary.org/reference/pkgs/dbms_undo_adv.html
Regards,
John Thomas
Database Designer and Administrator
https://oracleexpert.net
On Tue, 29 Jan 2019 at 04:12, Jack van Zanen <jack@xxxxxxxxxxxx> wrote:
Hi All
We are getting ORA-1555 on one of our daily extracts and I need to explain
to the business why it is happening.
ERROR at line 1:
ORA-01555: snapshot too old: rollback segment number 92 with name
"_SYSSMU92_3807070151$" too small
ORA-06512: at line 43
ORA-06512: at "SYS.DBMS_SQL", line 1726
ORA-06512: at line 24
I have an undo retention of 3 hours (query fails before that generally)
I have an undo tablespace that can grow to 400G and currently only at 120G
so it does not appear to be the usual suspects so I am thinking of setting
an event to capture more information to explain it better
would below give me more information why this is happening or is there a
better solution?
*alter system set events '1555 trace name errorstack level 3';*
My guess is that the same blocks are simply changed too many times during
the time of query so the rollback record required for CR is simply no
longer available.
Jack van Zanen
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