question: public int read ( String table , String key , Set < String > fields , HashMap < String , ByteIterator > result ) { long st = System . nanoTime ( ) ; int res = _db . read ( table , key , fields , result ) ; long en = System . nanoTime ( ) ; _measurements . measure ( "READ" , ( int ) ( ( en - st ) / 1000 ) ) ; _measurements . reportReturnCode ( "READ" , res ) ; return res ; }
target:  Read a record from the database. Each field/value pair from the result will be stored in a HashMap.