Question-4: Please map the following

1. SSTable
2. Compaction
3. Tombstone

1. Data written on Disk
2. Marker for column deletion in a Row
3. Used for consolidating data on the disk

1. A-1, B-3, C-2
2. A-1, B-2, C-3
3. A-2, B-3, C-1
4. A-2, B-1, C-3
5. A-3, B-2, C-1

Ans : A

Exp: Each time memory structure is full, then data will be written to disk using SSTable data file. Once written all the data automatically partitioned and replicated throughout the cluster. Then Cassandra will periodically consolidate the SSTable using compaction, which discards the obsolete data which is marked for deletion using tombstone marker. Tombstone is a marker in a row which indicates that a column should be deleted.