I've created a new Wiki page that describes a scheme for normalizing internal page items within B-Tree indexes, and the many optimizations that this can enable:
https://wiki.postgresql.org/wiki/Key_normalization Key normalization means creating a representation for internal page items that we always just memcmp(), regardless of the details of the underlying datatypes. My intent in creating this wiki page is to document these techniques centrally, as well as the problems that they may solve, and to show how they're all interrelated. It might be that confusion about how one optimization enables another holds back patch authors. It might appear excessive to talk about several different techniques in one place, but that seemed like the best way to me, because there are subtle dependencies. If most of the optimizations are pursued as a project all at once (say, key normalization, suffix truncation, and treating heap TID as a unique-ifier), that may actually be more likely to succeed than a project to do just one. The techniques don't appear to be related at first, but they really are. I'm not planning on working on key normalization or any of the other techniques as projects myself, but FWIW I have produced minimal prototypes of a few of the techniques over the past several years, just to verify my understanding. My theories on this topic seem worth writing down. I'm happy to explain or clarify any aspect of what I describe, and to revise the design based on feedback. It is still very much a work in progress. -- Peter Geoghegan -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
