BDA_Coursera

Lec 1

HBase: Hadoop's database

For Google Big table:
3 major Dimensions: Columns, Rows, Timestamps(per value)


Column key, 
HBase,bigtable(Colums oriented)
Column->Most basic unit of HBase

Timestampes->Keep different versions of data in one table in separate cells
Family of Columns-》stored in same Hfile

SYNTAX:NAME OF COLUMN KEY
family:qualifier

 

 

 

Row key
Rows->unit of transactional consistency
Grouping rows->tablets (Because tablets are distributed and stored close to each other->faster lookup)

 

 

HBase 的 master server先connect zookeeper再与 slave server交互