Quick question about why use a byte array to populate the usertable collection.

[morcelicaio]

Hello guys.

I had a question about the data that is generated for the database.

Why does YCSB use a Hashmap whose key value is a ByteIterator to fill in the data from the usertable collection in the DB? Why not use a String for example or another type of random value?

Is there any specific reason @busbey ?

[busbey]

Here's the javadoc from the ByteIterator class, which gives a rationale:

• YCSB-specific buffer class. ByteIterators are designed to support
• efficient field generation, and to allow backend drivers that can stream
• fields (instead of materializing them in RAM) to do so.
• YCSB originially used String objects to represent field values. This led to
• two performance issues.
• First, it leads to unnecessary conversions between UTF-16 and UTF-8, both
• during field generation, and when passing data to byte-based backend
• drivers.
• Second, Java strings are represented internally using UTF-16, and are
• built by appending to a growable array type (StringBuilder or
• StringBuffer), then calling a toString() method. This leads to a 4x memory
• overhead as field values are being built, which prevented YCSB from
• driving large object stores.

Mind you, this is from 10+ years ago.