IBM solidDB vs kdb+ comparison

IBM solidDB is a relational database server that combines the high performance of in-memory tables with the nearly unlimited capacity of disk-based tables.

Pure in-memory databases are fast, but strictly limited by the size of memory. Pure disk-based databases allow nearly unlimited amounts of storage, but their performance is dominated by disk access. Even if the computer has enough memory to store the entire database in memory buffers, database servers that are designed for disk-based tables can be slow because the data structures that are optimal for disk-based tables are far from being optimal for in-memory tables. The solidDB solution is to provide a single hybrid database server that contains two optimized engines inside it:

• The main-memory engine (MME) is optimized for in-memory access.
• The disk-based engine (DBE) is optimized for disk-based access.

Both engines coexist inside the same server process, and a single SQL statement can access data from both engines.