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| -- show running queries (pre 9.2) | |
| SELECT procpid, age(clock_timestamp(), query_start), usename, current_query | |
| FROM pg_stat_activity | |
| WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' | |
| ORDER BY query_start desc; | |
| -- show running queries (9.2) | |
| SELECT pid, age(clock_timestamp(), query_start), usename, query | |
| FROM pg_stat_activity | |
| WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%' |
| Latency Comparison Numbers (~2012) | |
| ---------------------------------- | |
| L1 cache reference 0.5 ns | |
| Branch mispredict 5 ns | |
| L2 cache reference 7 ns 14x L1 cache | |
| Mutex lock/unlock 25 ns | |
| Main memory reference 100 ns 20x L2 cache, 200x L1 cache | |
| Compress 1K bytes with Zippy 3,000 ns 3 us | |
| Send 1K bytes over 1 Gbps network 10,000 ns 10 us | |
| Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD |