Thiago Godoi wrote: > Hi all, > > I found this presentation from B. Momjian: > > http://momjian.us/main/writings/pgsql/performance.pdf > > I'm interested in what he said about " Intersect/Union X AND/OR " , Can I > find a transcription or a video of this presentation? Can anyone explain it > to me?
Well, there is a recording of the webcast on the EnterpriseDB web site, but I am afraid they only allow viewing of 3+ hour webcasts by EnterpriseDB customers. The idea is that a query that uses an OR can be rewritten as two SELECTs with a UNION between them. I have seen rare cases where this is a win, so I mentioned it in that talk. Intersection is similarly possible for AND in WHERE clauses. -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. + -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
