No real HFT system is doing a * database transaction * in the critical trading path. HFT systems are not built like web applications. They are typically built a

No real HFT system is doing a * database transaction * in the critical trading path. HFT systems are not built like web applications. They are typically built as a tight event loop, reading market data packets directly from the network card, doing a tiny bit of computation and then writing to a userspace TCP stack for order entry. I guess you could be using MemSQL for post-order or trade analysis but then it would probably overkill since a lot of that can be done considerably slower.