On Thu, Feb 22, 2018 at 1:14 PM, Tomas Vondra <tomas.von...@2ndquadrant.com> wrote: > OK, thanks for reminding me about SBF and for the discussion. > > At this point I'll probably focus on the other parts though - > determining selectivity of the join, etc. Which I think is crucial, and > we need to get that right even for accurate estimates. It's good to know > that we have a solution for that part, though.
+1 There are probably significant opportunities to improve the Bloom filter. That isn't that interesting right now, though. Figuring out how scalable Bloom filters might save hash join from being reliant on the accuracy of the initial estimate of set cardinality seems premature at best, since we haven't established how sensitive this use-case is to misestimations. My sense is that it's actually naturally very insensitive, but there is no need to spend too much time on it just yet. It just makes sense, as a matter of procedure, to focus on the hash join code, and drill down from there. Personally, I'm tired of talking about the nitty-gritty details of Bloom filters rather than the actual problem at hand. -- Peter Geoghegan
