[HDFS-10752] Several log refactoring/improvement suggestion in HDFS

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.7.2
• Fix Version/s: 2.8.0, 3.0.0-alpha2
• Labels: easyfix easytest
• Hadoop Flags: Reviewed
• Assignee: Hanisha Koneru
• Reporter: Nemo Chen
• Created: 11/Aug/16 18:13
• Updated: 20/Oct/16 00:40
• Resolved: 20/Oct/16 00:27

Description

As per conversation with vrushalic, we merged HDFS-10749, HDFS-10750, HDFS-10751, HDFS-10753, under this issue.

---

HDFS-10749
Method invocation in logs can be replaced by variable
Similar to the fix for HDFS-409. In file:

hadoop-rel-release-2.7.2/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSOutputStream.java

In code block:

lastQueuedSeqno = currentPacket.getSeqno();
if (DFSClient.LOG.isDebugEnabled()) {
    DFSClient.LOG.debug("Queued packet " + currentPacket.getSeqno());
}

currentPacket.getSeqno() is better to be replaced by variable lastQueuedSeqno.

---

HDFS-10750
Similar to the fix for AVRO-115. In file:

hadoop-rel-release-2.7.2/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNode.java

in line 695, the logging code:

LOG.info(getRole() + " RPC up at: " + rpcServer.getRpcAddress());

In the same class, there is a method in line 907:

  /**
   * @return NameNode RPC address
   */
  public InetSocketAddress getNameNodeAddress() {
    return rpcServer.getRpcAddress();
  }

We can tell that rpcServer.getRpcAddress() could be replaced by method getNameNodeAddress() for the case of readability and simplicity

---

HDFS-10751
Similar to the fix for AVRO-115. In file:

hadoop-rel-release-2.7.2/hadoop-hdfs-project/hadoop-hdfs-nfs/src/main/java/org/apache/hadoop/hdfs/nfs/nfs3/OpenFileCtxCache.java

in line 72, the logging code:

LOG.trace("openFileMap size:" + openFileMap.size());

In the same class, there is a method in line 189:

  int size() {
    return openFileMap.size();
  }

We can tell that openFileMap.size() could be replaced by method size() for the case of readability and simplicity

---

Print variable in byte
Similar to the fix for HBASE-623, in file:

hadoop-rel-release-2.7.2/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/BackupImage.java

In the following method, the log printed variable data (in byte[]). A possible fix is add Bytes.toString(data).

/**
   * Write the batch of edits to the local copy of the edit logs.
   */
  private void logEditsLocally(long firstTxId, int numTxns, byte[] data) {
    long expectedTxId = editLog.getLastWrittenTxId() + 1;
    Preconditions.checkState(firstTxId == expectedTxId,
        "received txid batch starting at %s but expected txn %s",
        firstTxId, expectedTxId);
    editLog.setNextTxId(firstTxId + numTxns - 1);
    editLog.logEdit(data.length, data);
    editLog.logSync();
  }

---

---

HDFS-10753
MethodInvocation replaced by variable due to toString method
Similar to the fix in HADOOP-6419, in file:

hadoop-rel-release-2.7.2/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/CorruptReplicasMap.java

in line 76, the blk.getBlockName() method invocation is invoked on variable blk. "blk" is the class instance of Block.

void addToCorruptReplicasMap(Block blk, DatanodeDescriptor dn,
      String reason, Reason reasonCode) {
...
NameNode.blockStateChangeLog.info(
          "BLOCK NameSystem.addToCorruptReplicasMap: {} added as corrupt on "
              + "{} by {} {}", blk.getBlockName(), dn, Server.getRemoteIp(),
          reasonText);

In file: hadoop-rel-release-2.7.2/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/Block.java

  @Override
  public String toString() {
    return getBlockName() + "_" + getGenerationStamp();
  }

The toString() method contain not only getBlockName() but also getGenerationStamp which may be helpful for debugging purpose. Therefore blk.getBlockName() can be replaced by blk

Issue Links

• supercedes: HDFS-10749 Log refactoring: method invocation should be replaced by variable
• supercedes: HDFS-10750 Log refactoring: method invocation should be replaced by a shorter method
• supercedes: HDFS-10751 Log refactoring: method invocation should be replaced by a shorter method
• supercedes: HDFS-10753 Method invocation in log can be replaced by variable because the variable's toString method contains more info