jboner

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

jacobbubu

mr	Marathi
bs	Bosnian
ee_TG	Ewe (Togo)
ms	Malay
kam_KE	Kamba (Kenya)
mt	Maltese
ha	Hausa
es_HN	Spanish (Honduras)
ml_IN	Malayalam (India)
ro_MD	Romanian (Moldova)

gladson

Sql	                                                    QuerySet	                                     Notes
SELECT count(*) FROM fruit	                      Fruits.objects.count()	                          table count
SELECT count(*) FROM fruit WHERE name=’Orange’        Fruits.objects.filter(name__exact=’Orange’).count() count with filter
SELECT * FROM fruit WHERE color is NULL	              Fruits.objects.get(color__isnull=True)	          filter by null
SELECT * FROM fruit WHERE color is NOT NULL	      Fruits.objects.get(color__isnull=False)	          filter by null
SELECT * FROM fruit WHERE name=’Apple’	              Fruits.objects.get(name__exact=’Apple’)	          case sensitive
SELECT * FROM fruit WHERE lower(name)=lower(‘Apple’)  Fruits.objects.get(name__iexact=’Apple’)            case in-sensitive
SELECT * FROM fruit WHERE name LIKE ‘App%’	      Fruits.objects.filter(name__startswith=’App’)       case sensitive LIKE
SELECT * FROM fruit WHERE upper(name) LIKE ‘APP%’     Fruits.objects.filter(name__ista