Any examples of production applications that use signature trees?

Question

I've been reading a lot lately about signature trees, or S-Trees. For example, this paper. The literature speaks very highly of them, and evidence is provided for considerable performance gains over, for example, inverted files or B-Trees, for some applications.

Now, why is it that I don't see S-Trees used very much? Do you know of any prominent instances of such a data structure in a popular application? Are there DBMS implementations that offer signature-tree indexes?

Answer 1

I've heard of something similar described as being a "C-tree" - it was part of an object database and I imagined that its indexing methods were similar to what the paper in the link described. A company called InterSystems makes a database system called Caché that they describe as "post-relational" and is very hierarchical ... I don't know enough about the details of these different systems to be sure that they're all different names for the same functionality, but, they have some overlapping fundamental concepts.

Answer 2

Now, why is it that I don't see S-Trees used very much?

Including a new indexing or join method into a database is a very complex task.

MySQL, for instance, doesn't yet impement MERGE JOIN and HASH JOIN that were invented by, like, ancient Romans or Archimedes or around that time.

And the paper you referenced is dated 2006 and this method isn't even mentioned in Wikipedia.

This means that it's either yet unknown to developers or isn't worth using it in an RDBMS (or both).