[hnkimb3558]

CockroachDB's time api is based on the Hybrid Logical Clocks paper. We credit it on our design doc (https://github.com/cockroachdb/cockroach/blob/master/docs/de...) and in the source code.

This blog post doesn't mention HLC because the explanation didn't require it. HLC boils down to a mechanism for taking the maximum physical wall time across >= 2 nodes, while still being able to provide monotonically increasing time via incrementing the logical component of the hybrid logical timestamp. In the blog post, this is referred to as "taking the maximum timestamp across requests". A segue into HLC would have served only to further complicate the explanation.

The work done by Sandeep Kulkarni, Murat Demirbas, David Alves, Todd Lipcon, Vijay Garg, and others was instrumental to our early design efforts. I am dismayed to see there's a patent pending, though both our design and open source implementation predate the patent filing.

[tlipcon]

FYI on the date issue, lest anyone think we filed the patent trying to steal the work done by others, the patent application says:

"This application claims to the benefit of U.S. Provisional Patent Application No. 61/911,720, entitled “HYBRIDTIME and HYBRIDCLOCKS FOR CLOCK UNCERTAINTY REDUCTION IN A DISTRIBUTED COMPUTING ENVIRONMENT”, which was filed on Dec. 4, 2013, which is incorporated by reference herein in its entirety."

(which predates the creation of the cockroachdb repo and the hybrid logical clock paper).