[HBASE-20917] MetaTableMetrics#stop references uninitialized requestsMap for non-meta region

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0-alpha-1, 1.4.6, 2.2.0, 2.0.4, 2.1.3
• Component/s: meta, metrics
• Hadoop Flags: Reviewed
• Assignee: Ted Yu
• Reporter: Ted Yu
• Created: 21/Jul/18 23:04
• Updated: 22/Mar/19 05:56
• Resolved: 15/Jan/19 20:47

Description

I noticed the following in test output:

2018-07-21 15:54:43,181 ERROR [RS_CLOSE_REGION-regionserver/172.17.5.4:0-1] executor.EventHandler(186): Caught throwable while processing event M_RS_CLOSE_REGION
java.lang.NullPointerException
  at org.apache.hadoop.hbase.coprocessor.MetaTableMetrics.stop(MetaTableMetrics.java:329)
  at org.apache.hadoop.hbase.coprocessor.BaseEnvironment.shutdown(BaseEnvironment.java:91)
  at org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost$RegionEnvironment.shutdown(RegionCoprocessorHost.java:165)
  at org.apache.hadoop.hbase.coprocessor.CoprocessorHost.shutdown(CoprocessorHost.java:290)
  at org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost$4.postEnvCall(RegionCoprocessorHost.java:559)
  at org.apache.hadoop.hbase.coprocessor.CoprocessorHost.execOperation(CoprocessorHost.java:622)
  at org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost.postClose(RegionCoprocessorHost.java:551)
  at org.apache.hadoop.hbase.regionserver.HRegion.doClose(HRegion.java:1678)
  at org.apache.hadoop.hbase.regionserver.HRegion.close(HRegion.java:1484)
  at org.apache.hadoop.hbase.regionserver.handler.CloseRegionHandler.process(CloseRegionHandler.java:104)
  at org.apache.hadoop.hbase.executor.EventHandler.run(EventHandler.java:104)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)

requestsMap is only initialized for the meta region.
However, check for meta region is absent in the stop method:

  public void stop(CoprocessorEnvironment e) throws IOException {
    // since meta region can move around, clear stale metrics when stop.
    for (String meterName : requestsMap.keySet()) {

Issue Links

• is related to: HBASE-19722 Meta query statistics metrics source