On Fri, Jul 22, 2022 at 10:43 AM Masahiko Sawada <sawada.m...@gmail.com> wrote: > > On Tue, Jul 19, 2022 at 1:30 PM John Naylor > <john.nay...@enterprisedb.com> wrote: > > > > > > > > On Tue, Jul 19, 2022 at 9:11 AM Masahiko Sawada <sawada.m...@gmail.com> > > wrote: > > > > > I’d like to keep the first version simple. We can improve it and add > > > more optimizations later. Using radix tree for vacuum TID storage > > > would still be a big win comparing to using a flat array, even without > > > all these optimizations. In terms of single-value leaves method, I'm > > > also concerned about an extra pointer traversal and extra memory > > > allocation. It's most flexible but multi-value leaves method is also > > > flexible enough for many use cases. Using the single-value method > > > seems to be too much as the first step for me. > > > > > > Overall, using 64-bit keys and 64-bit values would be a reasonable > > > choice for me as the first step . It can cover wider use cases > > > including vacuum TID use cases. And possibly it can cover use cases by > > > combining a hash table or using tree of tree, for example. > > > > These two aspects would also bring it closer to Andres' prototype, which 1) > > makes review easier and 2) easier to preserve optimization work already > > done, so +1 from me. > > Thanks. > > I've updated the patch. It now implements 64-bit keys, 64-bit values, > and the multi-value leaves method. I've tried to remove duplicated > codes but we might find a better way to do that. >
With the recent changes related to simd, I'm going to split the patch into at least two parts: introduce other simd optimized functions used by the radix tree and the radix tree implementation. Particularly we need two functions for radix tree: a function like pg_lfind32 but for 8 bits integers and return the index, and a function that returns the index of the first element that is >= key. Regards, -- Masahiko Sawada EDB: https://www.enterprisedb.com/
