Generally, in this field people also look at kdb from Kx Systems. I think both these systems really had they hay-day in the early 2000's. I would see if a tuned MySQL with a solid state RAID array would give you the performance you need.
BTW, I once wrote a time series database which outperformed both TimesTen and Kdb. It supported a SQL-92 syntax. The key to the performance was binding the schema to C++ template based classes, and using memory mapped files. Allowing for on-the-run schema changes is quite expensive, and defining the schema at compile time, data lookups could be retrieved in just a few assembly instructions.
