From 81f05bd9438a2bd1cc518c2727da50181caf3b20 Mon Sep 17 00:00:00 2001 From: Chia-Ping Tsai Date: Mon, 18 Dec 2017 17:43:44 +0800 Subject: [PATCH] HBASE-17967 clean up documentation references to -ROOT- table. --- src/main/asciidoc/_chapters/architecture.adoc | 29 +++---------------- 1 file changed, 4 insertions(+), 25 deletions(-) diff --git a/src/main/asciidoc/_chapters/architecture.adoc b/src/main/asciidoc/_chapters/architecture.adoc index e649a524611..d43074a7e85 100644 --- a/src/main/asciidoc/_chapters/architecture.adoc +++ b/src/main/asciidoc/_chapters/architecture.adoc @@ -88,31 +88,10 @@ See the <> 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 <>) 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.