We have one database with version 11.2.0.4 Exadata-X5 machine. We have IORM
objective kept as BASIC(which is default) and it's only one database in
that half RACK(~7 cell server) exadata cluster. We encountered performance
issue twice , where a ETL query doing FULL table/partition scan
repetitively for longer duration, causing the flash cache to be flooded
with large reads and the other low latency work load or small reads/index
reads getting suffered because of that, and so we had to kill the ETL query
to let the low latency workload perform in its normal speed.
I saw in a few blogs stating the IORM should be kept as AUTO and is
recommended. Wanted to understand from experts, if AUTO IORM setup is going
to help in such a situation, where we have only one database residing in
the exadata machine having multiple types of workloads(both OLTP and BATCH
types at same time) running in the same database? I am not seeing a clear
difference , how different is IORM objective AUTO from the BASIC incase of
single database IORM management?
