Example #1
0
 public void readTracker(ProcedureStoreTracker tracker) throws IOException {
   ProcedureWALTrailer trailer = readTrailer();
   try {
     stream.seek(trailer.getTrackerPos());
     tracker.readFrom(stream);
   } finally {
     stream.seek(startPos);
   }
 }
Example #2
0
  public static ProcedureWALTrailer readTrailer(FSDataInputStream stream, long startPos, long size)
      throws IOException {
    // Beginning of the Trailer Jump. 17 = 1 byte version + 8 byte magic + 8 byte offset
    long trailerPos = size - 17;

    if (trailerPos < startPos) {
      throw new InvalidWALDataException("Missing trailer: size=" + size + " startPos=" + startPos);
    }

    stream.seek(trailerPos);
    int version = stream.read();
    if (version != TRAILER_VERSION) {
      throw new InvalidWALDataException(
          "Invalid Trailer version. got " + version + " expected " + TRAILER_VERSION);
    }

    long magic = StreamUtils.readLong(stream);
    if (magic != TRAILER_MAGIC) {
      throw new InvalidWALDataException(
          "Invalid Trailer magic. got " + magic + " expected " + TRAILER_MAGIC);
    }

    long trailerOffset = StreamUtils.readLong(stream);
    stream.seek(trailerOffset);

    ProcedureWALEntry entry = readEntry(stream);
    if (entry.getType() != ProcedureWALEntry.Type.PROCEDURE_WAL_EOF) {
      throw new InvalidWALDataException("Invalid Trailer begin");
    }

    ProcedureWALTrailer trailer =
        ProcedureWALTrailer.newBuilder().setVersion(version).setTrackerPos(stream.getPos()).build();
    return trailer;
  }