# `Read` Operation
+ Point query 
  + `Bloom` filter avoids disk I/O 
  + At most physical read once 

+ Range scan 
  + `Bloom` filter cannot help 
  + Prefix-iterator (applied `bloom-filter`)
    + Ranges scans within same key prefix
    + `Bloom` created for key prefix only
    + Reduces the read amplification

![`smart`](ReadPenaltyOnLSM_aa_001_20221021.png)

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