On Fri, Aug 5, 2016 at 07:51:05PM -0300, Claudio Freire wrote: > > This does create more HOT chains where the root ctid cannot be removed, > > but it does avoid the index key/ctid check because any entry in the HOT > > chain has identical keys. What this would not handle is when an entire > > HOT chain is pruned, as the keys would be gone. > > I believe the only solution is to use bitmap index scans with WARM indexes.
Let me back up and explain the benefits we get from allowing HOT chains to be WARM: * no index entries for WARM indexes whose values don't change * improved pruning because the HOT/WARM chains can be longer because we don't have to break chains for index changes While I realize bitmap indexes would allow us to remove duplicate index entries, it removes one of the two benefits of WARM, and it causes every index read to be expensive --- I can't see how this would be a win over doing the index check on writes. -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + As you are, so once was I. As I am, so you will be. + + Ancient Roman grave inscription + -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers