toliklunev

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

toliklunev

Moved to git-repository: https://github.com/denji/awesome-http-benchmark

Tools

Located in alphabetical order (not prefer)

• ab – slow and single threaded, written in C
• apib – most of the features of ApacheBench (ab), also designed as a more modern replacement, written in C
• autocannon – fast HTTP/1.1 benchmarking tool written in Node.js
• baloo – Expressive end-to-end HTTP API testing made easy, written in Go (golang)

toliklunev

-- 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%'