As previously discussed [1], WARM is a technique to reduce write amplification when an indexed column of a table is updated. HOT fails to handle such updates and ends up inserting a new index entry in all indexes of the table, irrespective of whether the index key has changed or not for a specific index. The problem was highlighted by Uber's blog post [2], but it was a well known problem and affects many workloads.
I realised that the patches were bit-rotten because of 8e1e3f958fb. Rebased patches on the current master are attached. I also took this opportunity to correct some white space errors and improve formatting of the README.
