public String getDetailedReadPositionString() {
    return deserializeRead.getDetailedReadPositionString();
  }
Deserialize a row from the range of bytes specified by setBytes.

Use this method instead of deserialize when it is safe to retain references to the bytes source
for DeserializeRead.  I.e. the STRING, CHAR/VARCHAR data can be set in BytesColumnVector with
setRef instead of with setVal which copies data.

An example of a safe usage:
  Referring to bytes in a hash table entry that is immutable.

An example of a unsafe usage:
  Referring to bytes in a reduce receive buffer that will be overwritten with new data.

Use getDetailedReadPositionString to get detailed read position information to help
diagnose exceptions that are thrown...

@param batch
@param batchIndex
@throws IOException
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/VectorDeserializeRow.java