10 hours ago
- Performance in database systems consists of three main components: latency, operations per unit of time per core, and quality of operations.
- Latency measures the time for a query reply, with predictability and consistency being as important as average time.
- Operations per second per core distinguishes raw performance from scalability and relates to energy efficiency.
- Quality of operations reflects the value of each operation, such as performing complex tasks (e.g., INCR) in a single command, which can double performance for certain use cases.
- The importance of quality of operations varies by problem; it is especially critical in in-memory systems where computation time is minimal compared to command dispatch.
- High-quality operations can reduce latency and bandwidth usage by enabling more selective or complex replies, as seen with Redis commands like ZRANK or HMGET.