Changes between Version 19 and Version 20 of hbase_table_design

Timestamp:

09/19/2012 12:20:13 PM (14 years ago)

Author:

liaojiaohe

Comment:

--

hbase_table_design

@@ -17 +17 @@
 
  
-==      2、rowkey[[BR]] ==
+==      2.rowkey[[BR]] ==
 
 
@@ -27 +27 @@
 
 
-==       3、columnfamily[[BR]] ==
+==       3.columnfamily[[BR]] ==
 
 
@@ -33 +33 @@
 
 
-==       4、column[[BR]] ==
+==       4.column[[BR]] ==
 
 
@@ -40 +40 @@
      (2) column的数目不要超过百万，不然会出现OOM。如果column过多，可以考虑将column设计到rowkey的方法解决。例如原来的rowkey是uid1,，column是uid2，uid3...。重新设计之后rowkey为<uid1>~<uid2>，<uid1>~<uid3>...，采用scan(startkey,endkey)的扫描方法来读数据[[BR]]
 
+
+
+==     5.counter  ==
+使用counter自增可以保证操作的原子性
+
+
+{{{
+import java.io.IOException;
+ 
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.HBaseConfiguration;
+import org.apache.hadoop.hbase.client.HTable;
+import org.apache.hadoop.hbase.util.Bytes;
+ 
+public class test_counter {
+ 
+    public static void main(String[] args) throws IOException {
+ 
+        Configuration conf = null;
+        conf = HBaseConfiguration.create();
+        conf.set("hbase.zookeeper.quorum", "192.168.11.64");
+ 
+        HTable table = new HTable(conf, Bytes.toBytes("test_table"));
+        long c = table.incrementColumnValue(Bytes.toBytes("100"), Bytes.toBytes("cf1"),
+                Bytes.toBytes("column1"), 4);
+        table.close();
+ 
+    }
+ 
+}
+}}}