| From: | Andrey Lepikhov <a(dot)lepikhov(at)postgrespro(dot)ru> |
|---|---|
| To: | Peter Geoghegan <pg(at)bowt(dot)ie> |
| Cc: | Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>, Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru>, Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>, Claudio Freire <klaussfreire(at)gmail(dot)com>, Anastasia Lubennikova <a(dot)lubennikova(at)postgrespro(dot)ru> |
| Subject: | Re: Making all nbtree entries unique by having heap TIDs participate in comparisons |
| Date: | 2018-10-23 10:35:21 |
| Message-ID: | a3b46cc4-8767-a718-a9df-0aa166bd3378@postgrespro.ru |
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| Lists: | pgsql-hackers |
On 19.10.2018 0:54, Peter Geoghegan wrote:
> I would welcome any theories as to what could be the problem here. I'm
> think that this is fixable, since the picture for the patch is very
> positive, provided you only focus on bgwriter/checkpoint activity and
> on-disk sizes. It seems likely that there is a very specific gap in my
> understanding of how the patch affects buffer cleaning.
I have same problem with background heap & index cleaner (based on your
patch). In this case the bottleneck is WAL-record which I need to write
for each cleaned block and locks which are held during the WAL-record
writing process.
Maybe you will do a test without writing any data to disk?
--
Andrey Lepikhov
Postgres Professional
https://postgrespro.com
The Russian Postgres Company
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