3 ms·
Exactly what I thought. Microseconds? On HDD? That would mean the block is in RAM. HDD latency is composed of seek + rotation latency + processing time, on the
by mstaoru 7y ago
Exactly what I thought. Microseconds? On HDD? That would mean the block is in RAM.
HDD latency is composed of seek + rotation latency + processing time, on the best of the best server HDDs random read might be in the ballpark of 10ms (10,000μs), desktop HDD... maybe around 30-40ms (30,000μs). Or ~600x times more than 49μs.
- marcan_42 7y agoDesktop HDDs aren't that bad, but 100 IOPS is a good ballpark for back of the envelope estimates (10ms). The OP wrote their B-Tree to require 3 lookups, so assuming they really are single disk reads that's where I calculated 30ms.
- stryku2393 7y agoJust to confirm, the benchmarks are bad. Almost always the read parts of B-tree file are cached. I'll rewrite the benchmarks and update the results!