Shulou(Shulou.com)06/01 Report--

The processing of each region makes up for the deficiency of several filters limited in scan.

There are two types.

Observer watchers are equivalent to triggers

Endpoint terminal is equivalent to stored procedure

The following observer replaces the KeyValue whose row key is Jack before implementing the query

Import java.io.IOException;import java.util.List;import org.apache.hadoop.hbase.KeyValue;import org.apache.hadoop.hbase.client.Get;import org.apache.hadoop.hbase.coprocessor.BaseRegionObserver;import org.apache.hadoop.hbase.coprocessor.ObserverContext;import org.apache.hadoop.hbase.coprocessor.RegionCoprocessorEnvironment;import org.apache.hadoop.hbase.util.Bytes;public class RegionObserverTest extends BaseRegionObserver {private static byte [] fixed_rowkey = "Jack" .getBytes () @ Override public void postGet (ObserverContext c, Get get, List result) throws IOException {if (Bytes.equals (get.getRow (), fixed_rowkey)) {KeyValue kv = new KeyValue (get.getRow (), Bytes.toBytes ("time"), Bytes.toBytes ("time"), Bytes.toBytes (System. CurrentTimeMillis () Result.add (kv);}

Load coprocessor command

Disable 'students'alter' students', 'coprocessor'= >' hdfs://ns1/coprocessor.jar | com.hbase.RegionObserverTest | | 'enable' students'

Alter 'table_name', METHOD= >' table_att', 'coprocessor'= >' path | class | number | args'

Number represents the number of coprocessors

Delete the first coprocessor

Alter 'table_name', METHOD= >' table_att_unset',NAME= > 'coprocessor$1'

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