I've just encountered this article describing how Alibaba does hardware acceleration in their database system [1]. They developed their own storage engine for MySQL (X-Engine) which is based on LSM data structure and using FPGA to accelerate levels compaction:
"In addition, FPGA hardware is used to accelerate the compaction process, further maximizing the performance of the system. This marks the first time that hardware acceleration was applied to the storage engine of an OLTP database."
There is also white paper on this [2]. It all looks really promising.
