This is our first release as a top-level Apache project! Thanks to everyone who has contributed to it.
In addition to a large number of bug fixes and minor enhancements, this release includes major improvements to Avatica, planner rules, and RelBuilder.
Further, we built Piglet, a subset of the classic Hadoop language Pig. Pig is particularly interesting because it makes heavy use of nested multi-sets. You can follow this example to implement your own query language, and immediately taking advantage of Calcite's back-ends and optimizer rules.