&gt; KDB is a single box timeseries<p>It’s not limited to a single box.  “single box” is the easiest setup, but by no means the common use case.  Kdb+ can be, and is, used across multiple servers and multiple storage devices.<p>&gt; the closest open source analogue would probably be using Pandas + a big folder of CSV files<p>I’m not familiar with Pandas, but I know what “a big folder of CSV files” looks like and that’s pretty far from kdb+.   Historical&#x2F;disk data is typically organized as “splayed&#x2F;parted” tables, which means it’s column oriented, sorted, grouped&#x2F;hashed by key columns, can be distributed across multiple devices[1], and has built-in compression.  So yes, operating over binary data, with a well-organized physical layout, and some optimized data structures is going to be much faster, not to mention the implied storage&#x2F;server cost savings.<p>&gt; Also KDB pricing starts at $100k or something like that.<p>I wish Kx were more open about this, but this is not very accurate.  You pay per CPU core, or for query throughput.  The size of your data, or number of users doesn’t matter, so you can start-out for 1&#x2F;10th this cost.  Of course your need for query throughput will correlate with things like number of users&#x2F;clients and size of your data.  But the licensing model is pretty simple, and seems to fit well with how user access scales.<p>I know Kx makes the argument that the licensing costs are more than offset by the reduced server footprint.  Personally, I’d love to see an actual case study that shows costs for a open-source database solution (with some performance metrics&#x2F;benchmarks), while a kdb+ performance-equivalent solution costs less (and projected to scale for less).  I know that’s a complicated comparison, where you’d really need to account for things like developer&#x2F;admin time&#x2F;salaries, not just equipment&#x2F;bandwidth&#x2F;storage&#x2F;licensing costs.  But it would be great to at least see a cost comparison on the latter dimensions.<p>[1] - <a href="http:&#x2F;&#x2F;code.kx.com&#x2F;wiki&#x2F;JB:KdbplusForMortals&#x2F;kdbplus_database#1.6.2_The_Physical_Layout_of_a_kdb.2B_Database" rel="nofollow">http:&#x2F;&#x2F;code.kx.com&#x2F;wiki&#x2F;JB:KdbplusForMortals&#x2F;kdbplus_databas...</a>