[HBASE-15252] Data loss when replaying wal if HDFS timeout

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 1.2.0, 1.3.0, 1.0.3, 1.1.3, 0.98.17, 2.0.0
• Fix Version/s: 1.2.0, 1.3.0, 1.1.4, 1.0.4, 0.98.18, 2.0.0
• Component/s: wal
• Hadoop Flags: Reviewed
• Assignee: Duo Zhang
• Reporter: Duo Zhang
• Created: 11/Feb/16 03:40
• Updated: 12/Feb/16 17:27
• Resolved: 12/Feb/16 13:21

Description

This is a problem introduced by HBASE-13825 where we change the exception type in catch block in readNext method of ProtobufLogReader.

ProtobufLogReader.java

      try {
          ......
          ProtobufUtil.mergeFrom(builder, new LimitInputStream(this.inputStream, size),
            (int)size);
        } catch (IOException ipbe) { // <------ used to be InvalidProtocolBufferException
          throw (EOFException) new EOFException("Invalid PB, EOF? Ignoring; originalPosition=" +
            originalPosition + ", currentPosition=" + this.inputStream.getPos() +
            ", messageSize=" + size + ", currentAvailable=" + available).initCause(ipbe);
        }

Here if the inputStream throws an IOException due to timeout or something, we just convert it to an EOFException and at the bottom of this method, we ignore EOFException and return false. This cause the upper layer think we reach the end of file. So when replaying we will treat the HDFS timeout error as a normal end of file and cause data loss.