SingleStore, a relational database, utilizes skiplist indexes instead of traditional B-tree or similar structures for in-memory data. This choice is driven by the need for memory-optimized and simple indexing that can be easily implemented in a lock-free fashion, making it fast and flexible. The use of skiplists eliminates the overhead associated with indirection, reducing the number of instructions required to insert, delete, search, or iterate over data. In contrast, traditional databases like MySQL rely on more complex locking schemes and have higher memory overhead due to page splitting and fragmentation. SingleStore's implementation of skiplist indexes results in significant performance improvements, particularly when compared to B-tree implementations like those found in SQL Server and InnoDB, with advantages extending to concurrent write workloads and reverse iteration support.