ScannerTimeoutException(转载)

在对Hbase进行Scan的时候有时候会抛出ScannerTimeoutException，场景如下：

 

2012 15:28:52 (14mins, 41sec)
org.apache.hadoop.hbase.client.ScannerTimeoutException: 60622ms passed since the last invocation, timeout is currently set to 60000
    at org.apache.hadoop.hbase.client.HTable$ClientScanner.next(HTable.java:1196)
    at org.apache.hadoop.hbase.mapreduce.TableRecordReaderImpl.nextKeyValue(TableRecordReaderImpl.java:133)
    at org.apache.hadoop.hbase.mapreduce.TableRecordReader.nextKeyValue(TableRecordReader.java:142)
    at org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.nextKeyValue(MapTask.java:532)
    at org.apache.hadoop.mapreduce.MapContext.nextKeyValue(MapContext.java:67)
    at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:143)
    at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
    at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:396)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1093)
    at org.apache.hadoop.mapred.Child.main(Child.java:249)

 

原因查看步骤： 

查找源码如下：

 

long timeout = lastNext + scannerTimeout;
             // If we are over the timeout, throw this exception to the client
             // Else, it's because the region moved and we used the old id
             // against the new region server; reset the scanner.
             if (timeout < System.currentTimeMillis()) {
               long elapsed = System.currentTimeMillis() - lastNext;
               ScannerTimeoutException ex = new ScannerTimeoutException(
                   elapsed + "ms passed since the last invocation, " +
                       "timeout is currently set to " + scannerTimeout);
               ex.initCause(e);
               throw ex;
             }

 

 核实下如下代码

 

long timeout = lastNext + scannerTimeout;

得出：ClientScanner.lastNext和HTable.scannerTimeout

 

 跟踪：HTable.scannerTimeout

 

this.scannerTimeout =
     (int) conf.getLong(HConstants.HBASE_REGIONSERVER_LEASE_PERIOD_KEY, HConstants.DEFAULT_HBASE_REGIONSERVER_LEASE_PERIOD);

 

 查看HConstants.HBASE_REGIONSERVER_LEASE_PERIOD_KEY和HConstants.DEFAULT_HBASE_REGIONSERVER_LEASE_PERIOD

我们可以得知如果没有设置HConstants.HBASE_REGIONSERVER_LEASE_PERIOD_KEY那么他们采用默认值即

 

public static long DEFAULT_HBASE_REGIONSERVER_LEASE_PERIOD = 60000;

 跟踪：ClientScanner.lastNext发现此为上次访问时间

解决方案：

可以通过设置HConstants.HBASE_REGIONSERVER_LEASE_PERIOD_KEY解决

代码如下：

 

config.setLong(HConstants.HBASE_REGIONSERVER_LEASE_PERIOD_KEY, 120000);