# Quiz

+ What are the following statements about reads and writes DML statements correct? (Select 2)
  + `A` . The main purpose of the.region cache is to cache hot data and reduce the number of times TiKV is accessed
  + `B` . Two-stage commit When getting the TSO that started the transaction and the submitted TSO, both are done by the TiDB Server
  + `C` . Schedule module uses latch to control that data currently being written is not read
  + `D` . On write operations, lock information is also written to RocksDB KV

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B, D