HDFS-16153. Avoid evaluation of LOG.debug statement in QuorumJournalManager (#3269). Contributed by wangzhaohui.

Author: wzhallright

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/client/QuorumJournalManager.java

@@ -586,7 +586,7 @@ private void selectRpcInputStreams(Collection<EditLogInputStream> streams,
  responseCounts.get(responseCounts.size() - loggers.getMajoritySize());
  if (maxAllowedTxns == 0) {
  LOG.debug("No new edits available in logs; requested starting from " +
- "ID " + fromTxnId);
+ "ID {}", fromTxnId);
  return;
  }
  LogAction logAction = selectInputStreamLogHelper.record(fromTxnId);
@@ -618,9 +618,10 @@ private void selectStreamingInputStreams(
  Map<AsyncLogger, RemoteEditLogManifest> resps =
  loggers.waitForWriteQuorum(q, selectInputStreamsTimeoutMs,
  "selectStreamingInputStreams");
-
- LOG.debug("selectStreamingInputStream manifests:\n" +
- Joiner.on("\n").withKeyValueSeparator(": ").join(resps));
+ if (LOG.isDebugEnabled()) {
+ LOG.debug("selectStreamingInputStream manifests:\n {}",
+ Joiner.on("\n").withKeyValueSeparator(": ").join(resps));
+ }
 
  final PriorityQueue<EditLogInputStream> allStreams =
  new PriorityQueue<EditLogInputStream>(64,