[HDFS-14179] BlockReaderRemote#readNextPacket() should log the waiting time for packet read.

• Type: Bug
• Status: Patch Available
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.0.0
• Component/s: hdfs-client
• Labels: newbie
• Assignee: Shubham Dewan
• Reporter: Surendra Singh Lilhore
• Created: 28/Dec/18 13:31
• Updated: 20/Jan/19 10:32

Description

Sometime read is reported very slow due to disk or some other reason. BlockReaderRemote#readNextPacket() should print the datanode IP and waiting time in trace log.

//Read packet headers.
packetReceiver.receiveNextPacket(in);

PacketHeader curHeader = packetReceiver.getHeader();
curDataSlice = packetReceiver.getDataSlice();
assert curDataSlice.capacity() == curHeader.getDataLen();

LOG.trace("DFSClient readNextPacket got header {}", curHeader);