On Mon, Jul 10, 2017 at 3:40 PM, Peter Geoghegan <p...@bowt.ie> wrote: > 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 do have a patch that attacks suffix truncation, heap tid unification and prefix compression all at once. It's on a hiatus ATM, but, as you say, the implementations are highly correlated so attacking them at once makes a lot of sense. Or, at least, attacking one having the other in the back of your mind. Key normalization would simplify prefix compression considerably, for instance. A missing optimization is that having tid unification allows VACUUM to implement a different strategy when it needs to clean up only a tiny fraction of the index. It can do the lookup by key-tid instead of scanning the whole index, which can be a win if the index is large and the number of index pointers to kill is small. -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers