Database Reference
In-Depth Information
Locking
Row updates are atomic, no matter how many row columns constitute the row-level trans-
action. This keeps the locking model simple.
Implementation
Just as HDFS and YARN are built of clients, workers, and a coordinating master — the
namenode
and
datanodes
in HDFS and
resource manager
and
node managers
in YARN
— so is HBase made up of an HBase
master
node orchestrating a cluster of one or more
regionserver
workers (see
Figure 20-2
). The HBase master is responsible for bootstrap-
ping a virgin install, for assigning regions to registered regionservers, and for recovering
regionserver failures. The master node is lightly loaded. The regionservers carry zero or
more regions and field client read/write requests. They also manage region splits, inform-
ing the HBase master about the new daughter regions so it can manage the offlining of
parent regions and assignment of the replacement daughters.
