Special Tables ROOT , META

Hbase In Action

• Two special tables in HBase, -ROOT- and .META., help find where regions for various tables are hosted.

• Like all tables in HBase, -ROOT- and .META. are also split into

  regions. -ROOT- and .META. are both special tables, but -ROOT- is more special than

  .META.; -ROOT- never splits into more than one region.

• .META. behaves like all other

  tables and can split into as many regions as required.

HBase Meta Table

• This META table is an HBase table that keeps a list of all regions in the system.

• The .META. table is like a b tree.

• The .META. table structure is as follows:

  • Key: region start key,region id

  • Values: RegionServer