| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Peter Geoghegan <pg(at)bowt(dot)ie> |
| Cc: | Anastasia Lubennikova <a(dot)lubennikova(at)postgrespro(dot)ru>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: [HACKERS] [WIP] Effective storage of duplicates in B-tree index. |
| Date: | 2019-12-18 01:17:58 |
| Message-ID: | 20191218011758.GF30116@momjian.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Tue, Dec 17, 2019 at 03:30:33PM -0800, Peter Geoghegan wrote:
> With many real world unique indexes, the true reason behind most or
> all B-Tree page splits is "version churn". I view these page splits as
> a permanent solution to a temporary problem -- we *permanently*
> degrade the index structure in order to deal with a *temporary* burst
> in versions that need to be stored. That's really bad.
Yes, I was thinking why do we need to optimize duplicates in a unique
index but then remembered is a version problem.
--
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 +
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