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);