10.7 preview feature JSON Histograms

MariaDB has had support for histograms as part of Engine Independent Table Statistics since 10.0. As part of Google Summer of Code (MDEV-21130), Michael Okoko, together with his mentor Sergey Petrunia, have implemented a new format (using JSON) for histograms that significantly improves the accuracy and flexibility of histograms. For those just interested in the feature details, you can skip to the “New format”, however if one is unfamiliar with the purpose of histograms, read on.

Why statistics are needed

Histograms are important for queries where the WHERE clause uses columns that are not indexed.