Access type | Actual time | Approximated time |
---|---|---|
1 CPU cycle | 0.3 ns | 1 s |
Level 1 cache access | 0.9 ns | 3 s |
Level 2 cache access | 2.8 ns | 9 s |
Level 3 cache access | 12.9 ns | 43 s |
Main memory access | 120 ns | 6 min |
Solid-state disk I/O | 50-150 μs | 2-6 days |
Rotational disk I/O | 1-10 ms | 1-12 months |
Internet: SF to NYC | 40 ms | 4 years |
Internet: SF to UK | 81 ms | 8 years |
Internet: SF to Australia | 183 ms | 19 years |
pg_prepared_statements
to see what is cached. Note thatit is not available across sessions and visible only to the current session.iotop
to measure writes/reads.create extension pg_stat_statements