DB - 11gR2
Users were running select queries on Primary where as the same select was failing with ORA-01555 in Active standby.
Undo_retention = 900 sec --Primary
Undo_retention = 21600 sec --Standby
Inspite of higher retention at standby users were facing ORA-01555.
Later realized that undo_retention at stantby does not have any significance. Oracle Dataguard just replicates the undo_retention value from Primary. Increased the Undo_retention in Primary to get rid of this error.
Below note really helped in understanding this.
http://alexeymoseyev.wordpress.com/2013/10/24/ora-01555-on-standby/
Users were running select queries on Primary where as the same select was failing with ORA-01555 in Active standby.
Undo_retention = 900 sec --Primary
Undo_retention = 21600 sec --Standby
Inspite of higher retention at standby users were facing ORA-01555.
Later realized that undo_retention at stantby does not have any significance. Oracle Dataguard just replicates the undo_retention value from Primary. Increased the Undo_retention in Primary to get rid of this error.
Below note really helped in understanding this.
http://alexeymoseyev.wordpress.com/2013/10/24/ora-01555-on-standby/
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