Add transaction workload

[martijndeheus]

Hello!

Thanks for the work you have done!

I was looking for a benchmark to test a system which does have transaction features, but simpler than TPCC. I stumbled upon YCSB+T (#169). I wanted something like this, unfortunately this was never merged.

I implemented something similar myself. It is a very simple closed economy model. It adds an integer field to the documents (balance) and adds a transfer operation to the DB. This transfer operation represents a transaction where a certain amount of balance is subtracted from one document and added to another.

For this to work I also added an insert operation where the workload can set an initial balance for the documents. I also added a deleteAndTransfer operation. This deletes a document and transfers all of its balance to another document.

The implementation of these "transactional" operations (transfer and deleteAndTransfer) is left to the DB binding.

I created a workload which includes these new operations.

I also added a REST client binding which implements the new operations.

I think I will add a validation step (as described in #169) as well.

I am interested to hear what you think of this addition and whether you think it could be a good addition to YCSB.

[morcelicaio]

Hello @martijndeheus , is this functionality already working in the latest version of YCSB?
I'm also looking for a benchmark to test a system with transaction capabilities.

[martijndeheus]

No, this work was never completed. I ended up making my own implementation of the YCSB+T benchmark in Python for the needs of my experiments.