After doing a SwitchOver from Production to standby(open read only), We were facing frequent ORA-01555 error.
This is a Oracle bug in 11.2 as per the below oracle doc.
Bug 22241601 ORA-600 [kdsgrp1] / ORA-1555 / ORA-600 [ktbdchk1: bad dscn] / ORA-600 [2663] due to Invalid Commit SCN in INDEX ( Doc ID 1608167.1 ).
As a solution we need to set below parameter on Production and standby.
alter system set "_ktb_debug_flags"=8 scope=both;
After this there was no issue in queries running in standby database.
This is a Oracle bug in 11.2 as per the below oracle doc.
Bug 22241601 ORA-600 [kdsgrp1] / ORA-1555 / ORA-600 [ktbdchk1: bad dscn] / ORA-600 [2663] due to Invalid Commit SCN in INDEX ( Doc ID 1608167.1 ).
As a solution we need to set below parameter on Production and standby.
alter system set "_ktb_debug_flags"=8 scope=both;
After this there was no issue in queries running in standby database.