The logical size includes all data in the spill files and b-trees (row keys, columns, values, timestamps, and indexes). It's almost equal to the physical size if compression is not enabled. Usually, the logical size is a bit smaller than the physical size since MapR-DB has some internal overhead. If compression is enabled, the logical size is usually much larger than physical size.
Remember that column names are repeated in the data saved (like HBase) in the logical size of a table. Row keys and CFs are not repeated with each cell. If you write a lot of data with large column names, the column names are repeated for every row—they can consume a lot of space.
Retrieving data ...