Wednesday, 30 March 2016

gc current block busy

gc current block busy

Definition

- An instance request for any data block in current mode, it send a request to the master.
- If master is the holder of that data block and also has already modified that block.
- Then master will retain PI block for itself.
- Master will also flush respective redo log to log file before sending CURRENT block to requesting instance.
- Now the block transfer delayed on requsting instance.
- Meanwhile requesting instance will wait in "gc current block busy"

Reason

- The block was being used by a session on another instance.
- The block transfer was delayed because the holding instance could not write the corresponding redo record to the online redo log file.


Troubleshooting

 - Tune LGWR
- Appropriate Application Partitioning
- Tune N/w

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