private int getFieldSize(Field field) {
    return Strings.nullToEmpty((String) get(field)).length() * Character.BYTES;
  }
Returns an estimated size of this record in bytes. This is used by the QueryHistoryService to sum the sizes of
records to decide if it needs to persist them (to prevent holding too many history records in memory).
This is a rough estimation in 2 steps:
1. Given a base size of the presumably "short" fields (String lengths are considered to be a constant)
2. Add the size of the "long" fields
@return estimatedSizeInMemoryBytes
ql/src/java/org/apache/hadoop/hive/ql/queryhistory/schema/Record.java