On Fri, Aug 5, 2016 at 12:25:39PM -0300, Claudio Freire wrote: > > 2. The existence of index pointers to intermediate tuples will lead to index > > bloat. This is the same problem that we found in Simon's original proposal > > (discussed internally). None of the intermediate line pointers can be > > vacuumed until the entire chain becomes DEAD. Event if the a duplicate index > > key is inserted for every index, knowing that and reclaiming to the index > > pointers to the original root line pointer, will be difficult. > > I don't see the difference it makes for bloat between storing the root > tid and the intermediate tid, but I haven't yet figured out how > vacuuming would work so maybe I have to think about that to realize > the difference.
Think of page pruning --- we can't remove a ctid that an index points to. The more ctids you point to in a HOT chain, the fewer ctids you can remove --- that's why we want to point only to the head of the HOT/WARM chain. -- 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