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1. If checkpoint failed it should restore physical records from WAL, as usual).
2. If checkpoint was not invoked reencryption is started from the beginning using saved logical WAL record.

// TBD

Risks and assumptions

• Background re-encryption can affect performancemay affect performance. Performance impact can be managed using following properties:
  1. IGNITE_REENCRYPTION_THREAD_POOL_SIZE - number of threads used for reencryption.
     
  2. IGNITE_REENCRYPTION_BATCH_SIZE - number of pages that is scanned during reencryption under checkpoint lock.
     
  3. IGNITE_REENCRYPTION_THROTTLE - delay in milliseconds between batches during a partition scanning.
     
• The WAL history can be not enough to store all entries between checkpoints (this should be carefully tuned by properly setting the size of the WAL history and tuning the re-encryption performance).
• The WAL history (for delta rebalancing) may be lost for all cache groups due to background re-encryption.

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