I have been trying to implement a storage function for Apache Pig that writes data in Trevni format. I found that the storage function was very slow when reading whole records.
I did some profiling (with Yourkit) and found that most of the CPU time was being spent in org.apache.trevni.InputBuffer$readString() (specifically in the String() method). I changed to java.nio.charset.CharsetDecoder.decode for deserialization and saw a big improvement. Changes are included in the patch.