Final answer:
The conversion of a Memtable to an SSTable in database systems is known as compaction. This process is crucial for database performance and efficient storage management.
Step-by-step explanation:
The process of turning a Memtable into an SSTable is called compaction. In database systems like Apache Cassandra, after a write comes in, it is written to the commit log for durability and then written to the Memtable, which is a memory-resident data structure. Once the Memtable accumulates enough data, it is made immutable and a new Memtable is started. The immutable Memtable is flushed to disk as an SSTable (Sorted String Table) in a process referred to as compaction. This process is essential to maintain the database's performance and durability by merging and compacting the data files on disk, thus aiding in efficient storage management and quicker read operations due to fewer and more organized data files.