[HDFS-16074] Remove an expensive debug string concatenation - ASF JIRA

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Details

Type: Improvement
Status: Resolved
Priority: Major
Resolution: Fixed
Affects Version/s: 3.0.0-alpha1
Fix Version/s: 3.4.0, 3.2.3, 3.3.2
Component/s: hdfs-client
Labels:
- pull-request-available

Target Version/s:

3.4.0, 3.2.3, 3.3.2
Hadoop Flags:

Reviewed

Description

Running a YCSB load query, found that we do an expensive string concatenation on the write path in DFSOutputStream.writeChunkPrepare().

Nearly 25% of HDFS client write CPU time is spent here. It is not necessary because it's supposed to be a debug message. So let's remove it.

 if (currentPacket == null) {
      currentPacket = createPacket(packetSize, chunksPerPacket, getStreamer()
          .getBytesCurBlock(), getStreamer().getAndIncCurrentSeqno(), false);
      DFSClient.LOG.debug("WriteChunk allocating new packet seqno={},"
              + " src={}, packetSize={}, chunksPerPacket={}, bytesCurBlock={}",
          currentPacket.getSeqno(), src, packetSize, chunksPerPacket,
          getStreamer().getBytesCurBlock() + ", " + this); <---- here
    }