SS Tea Table

Sorted Strings Table (SSTable) is a persistent file format used by ScyllaDB, Apache Cassandra, and other NoSQL databases to take the in-memory data stored in memtables, order it for fast access, and store it on disk in a persistent, ordered, immutable set of files. Immutable means SSTables are never modified.SSTable means Sorted String Table. They contain hashed string representations of data rows, sorted by a token. Several other files exist that support the Cassandra read process in telling if particular data is in a particular SSTable and in getting that data quickly from the file.Apache Cassandra compaction is the process of reconciling different data copies stored in different SSTables. Cassandra compaction of SSTables is a crucial background activity for maintenance and performance. Compaction in Cassandra involves various techniques and different timing for performing different operations.To satisfy a read, Cassandra must combine results from the active memtable and potentially multiple SSTables. Cassandra processes data at several stages on the read path to discover where the data is stored, starting with the data in the memtable and finishing with SSTables: Check the memtable.