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
