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HBASE-17967 clean up documentation references to -ROOT- table.

This commit is contained in:
Chia-Ping Tsai 2017-12-18 17:43:44 +08:00
parent 2cfb89c54d
commit 81f05bd943
1 changed files with 4 additions and 25 deletions
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29
src/main/asciidoc/_chapters/architecture.adoc
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@ -88,31 +88,10 @@ See the <<datamodel>> and the rest of this chapter for more information on how H
The catalog table `hbase:meta` exists as an HBase table and is filtered out of the HBase shell's `list` command, but is in fact a table just like any other.
[[arch.catalog.root]]
=== -ROOT-
NOTE: The `-ROOT-` table was removed in HBase 0.96.0.
Information here should be considered historical.
The `-ROOT-` table kept track of the location of the `.META` table (the previous name for the table now called `hbase:meta`) prior to HBase 0.96.
The `-ROOT-` table structure was as follows:
.Key
* .META.
region key (`.META.,,1`)
.Values
* `info:regioninfo` (serialized link:http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/HRegionInfo.html[HRegionInfo] instance of `hbase:meta`)
* `info:server` (server:port of the RegionServer holding `hbase:meta`)
* `info:serverstartcode` (start-time of the RegionServer process holding `hbase:meta`)
[[arch.catalog.meta]]
=== hbase:meta
The `hbase:meta` table (previously called `.META.`) keeps a list of all regions in the system.
The location of `hbase:meta` was previously tracked within the `-ROOT-` table, but is now stored in ZooKeeper.
The `hbase:meta` table (previously called `.META.`) keeps a list of all regions in the system, and the location of `hbase:meta` is stored in ZooKeeper.
The `hbase:meta` table structure is as follows:
@ -696,9 +675,9 @@ Your data is not the only resident of the block cache.
Here are others that you may have to take into account:
Catalog Tables::
The `-ROOT-` (prior to HBase 0.96, see <<arch.catalog.root,arch.catalog.root>>) and `hbase:meta` tables are forced into the block cache and have the in-memory priority which means that they are harder to evict.
The former never uses more than a few hundred bytes while the latter can occupy a few MBs
(depending on the number of regions).
The `hbase:meta` table is forced into the block cache and have the in-memory priority which means that they are harder to evict.
NOTE: The hbase:meta tables can occupy a few MBs depending on the number of regions.
HFiles Indexes::
An _HFile_ is the file format that HBase uses to store data in HDFS.