Scaling Reads easy
Why is reading data from Redis (In-Memory) faster than reading from PostgreSQL (Disk)?
- A Redis uses a better network cable.
- B PostgreSQL is badly written.
- C Accessing RAM is orders of magnitude faster (nanoseconds) than waiting for mechanical or flash disk I/O (milliseconds).
- D Redis compresses data better.
Answer: C. Accessing RAM is orders of magnitude faster (nanoseconds) than waiting for mechanical or flash disk I/O (milliseconds).
The physics of hardware dictate performance. RAM is directly addressable by the CPU controller, whereas Disk requires sending signals over a bus to a slower storage device.
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