When a CQL SELECT statement is executed with WHERE clause, Read Count is incremented in cfstats of the column family. But, when a full row scan is done using SELECT statement without WHERE clause, Read Count is not incremented.
Similarly, when using Size Tiered Compaction, if we do a full row scan using Hector RangeslicesQuery, Read Count is not incremented in cfstats, Cassandra still considers all sstables as cold and does not trigger compaction for them. If we fire MultigetSliceQuery, Read Count is incremented and sstables becomes hot, triggering compaction of these sstables.
1. Read Count must be incremented by number of rows read during a full row scan done using CQL SELECT statement or Hector RangeslicesQuery.
2. Size Tiered compaction must consider all sstables as Hot after a full row scan.