| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
| Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Lossy Index Tuple Enhancement (LITE) |
| Date: | 2016-08-03 23:56:00 |
| Message-ID: | 20160803235600.GC1702@momjian.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Wed, Aug 3, 2016 at 07:28:52PM -0400, Bruce Momjian wrote:
> With LITE, you can avoid the creation of duplicate-value index entries
> for indexes without changed column values by using a bitmap in place of
> the tid item number (16 bits). It can't remove dead tids.
How would you handle the case where there are two LITE index entries
pointing to two different update chains on the same page? When you
search the page for the first heap chain, could the second index entry
find the same chain. How would you know which index entry is which
chain? Would you only add a LITE index entry when there isn't an
existing index entry for the same values and heap page? That seems
quite complicated.
--
Bruce Momjian <bruce(at)momjian(dot)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 +
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Kyotaro HORIGUCHI | 2016-08-04 00:07:33 | Re: Possible duplicate release of buffer lock. |
| Previous Message | Michael Paquier | 2016-08-03 23:54:50 | Re: regression test for extended query protocol |