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Known Issues and Recommendations related to MIRA from 12.2 Onwards (Exadata and Non Exadata envirnoment) (Doc ID 2678711.1)

Last updated on MARCH 11, 2022

Applies to:

Oracle Database - Enterprise Edition - Version and later
Information in this document applies to any platform.


This Document lists down known issues related to MIRA and few recommendation when using it on Exadata .

Starting with Oracle Database 12.2, Multi-Instance Redo Apply (MIRA) greatly improves scalability of redo apply for
Oracle RAC databases. Instead of merging all threads of redo into a single apply process, multiple apply instances
divide the threads of redo between the apply instances. For example, when two apply nodes are used to apply four
threads of redo from the primary, each apply instance will apply two threads.

Important :- In Rac database it is recommended  to use single instance redo apply (SIRA) instead of MIRA when online patching for RAC rolling upgrade is in progress.




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