From 3039d610149aa9a633141bf41abcbd1923dcdff8 Mon Sep 17 00:00:00 2001
From: Kannan Muthukkaruppan <kannan@apache.org>
Date: Thu, 17 Nov 2011 23:01:59 +0000
Subject: [PATCH] HBASE-4628 [jira] Enhance Table Create Presplit Functionality
 within the HBase Shell

Summary:
HBase shell can algorithmically split a new table at creation

This change adds optional arguments to the HBase shell's create command
to split a table into a specified number of regions using a specified
splitting algorithm as defined by RegionSplitter.

Currently, we allow the user to presplit in the HBase shell by explicitly
listing the startkey of all the region shards that they want.  Instead, we
should provide the RegionSplitter functionality of choosing a split algorithm,
followed by the number of splits that they want.

Test Plan:
Created tables with and without splits using the shell; also attampted
to give incorrect arguments to shell create command.

Reviewers: nspiegelberg, JIRA

Reviewed By: nspiegelberg

CC: nspiegelberg, lhofhansl

Differential Revision: 429

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1203413 13f79535-47bb-0310-9956-ffa450edef68
---
 .../java/org/apache/hadoop/hbase/util/RegionSplitter.java | 2 +-
 src/main/ruby/hbase.rb                                    | 2 ++
 src/main/ruby/hbase/admin.rb                              | 8 ++++++++
 src/main/ruby/shell/commands/create.rb                    | 3 +++
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/apache/hadoop/hbase/util/RegionSplitter.java b/src/main/java/org/apache/hadoop/hbase/util/RegionSplitter.java
index 30f17ee2cc4..bd524e7ef4e 100644
--- a/src/main/java/org/apache/hadoop/hbase/util/RegionSplitter.java
+++ b/src/main/java/org/apache/hadoop/hbase/util/RegionSplitter.java
@@ -584,7 +584,7 @@ public class RegionSplitter {
    * @throws IOException if the specified SplitAlgorithm class couldn't be
    * instantiated
    */
-  static SplitAlgorithm newSplitAlgoInstance(Configuration conf,
+  public static SplitAlgorithm newSplitAlgoInstance(Configuration conf,
           String splitClassName) throws IOException {
     Class<?> splitClass;
 
diff --git a/src/main/ruby/hbase.rb b/src/main/ruby/hbase.rb
index 4d27191aea9..3ef4a82254f 100644
--- a/src/main/ruby/hbase.rb
+++ b/src/main/ruby/hbase.rb
@@ -53,6 +53,8 @@ module HBaseConstants
   FILTER = 'FILTER'
   SPLITS = 'SPLITS'
   SPLITS_FILE = 'SPLITS_FILE'
+  SPLITALGO = 'SPLITALGO'
+  NUMREGIONS = 'NUMREGIONS'
 
   # Load constants from hbase java API
   def self.promote_constants(constants)
diff --git a/src/main/ruby/hbase/admin.rb b/src/main/ruby/hbase/admin.rb
index 33cd2088fdf..02f01e20b2a 100644
--- a/src/main/ruby/hbase/admin.rb
+++ b/src/main/ruby/hbase/admin.rb
@@ -30,6 +30,7 @@ module Hbase
     def initialize(configuration, formatter)
       @admin = org.apache.hadoop.hbase.client.HBaseAdmin.new(configuration)
       connection = @admin.getConnection()
+      @conf = configuration
       @zk_wrapper = connection.getZooKeeperWatcher()
       zk = @zk_wrapper.getRecoverableZooKeeper().getZooKeeper()
       @zk_main = org.apache.zookeeper.ZooKeeperMain.new(zk)
@@ -198,6 +199,13 @@ module Hbase
             splits[idx] = split.to_java_bytes
             idx = idx + 1
           end
+        elsif arg.kind_of?(Hash) and (arg.has_key?(NUMREGIONS) or arg.has_key?(SLITALGO))
+          raise(ArgumentError, "Number of regions must be specified") unless arg.has_key?(NUMREGIONS)
+          raise(ArgumentError, "Split algorithm must be specified") unless arg.has_key?(SPLITALGO)
+          raise(ArgumentError, "Number of regions must be geter than 1") unless arg[NUMREGIONS] > 1
+          num_regions = arg[NUMREGIONS]
+          split_algo = org.apache.hadoop.hbase.util.RegionSplitter.newSplitAlgoInstance(@conf, arg[SPLITALGO])
+          splits = split_algo.split(JInteger.valueOf(num_regions))
         else
           # Add column to the table
           descriptor = hcd(arg, htd)
diff --git a/src/main/ruby/shell/commands/create.rb b/src/main/ruby/shell/commands/create.rb
index e67e8c1a180..14c1b0ff4f6 100644
--- a/src/main/ruby/shell/commands/create.rb
+++ b/src/main/ruby/shell/commands/create.rb
@@ -35,6 +35,9 @@ Examples:
   hbase> create 't1', {NAME => 'f1', VERSIONS => 1, TTL => 2592000, BLOCKCACHE => true}
   hbase> create 't1', 'f1', {SPLITS => ['10', '20', '30', '40']}
   hbase> create 't1', 'f1', {SPLITS_FILE => 'splits.txt'}
+  hbase> # Optionally pre-split the table into NUMREGIONS, using
+  hbase> # SPLITALGO ("HexStringSplit", "UniformSplit" or classname)
+  hbase> create 't1', 'f1', {NUMREGIONS => 15, SPLITALGO => 'HexStringSplit'}
 EOF
       end