Re: PostgreSQL and a Catch-22 Issue related to dead rows - Mailing list pgsql-performance

From Greg Sabino Mullane
Subject Re: PostgreSQL and a Catch-22 Issue related to dead rows
Date
Msg-id CAKAnmmL=_kuK2B6KtVpuCdta65MajTSvjQYSCdx=xhPLOW0shA@mail.gmail.com
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In response to PostgreSQL and a Catch-22 Issue related to dead rows  (Lars Aksel Opsahl <Lars.Opsahl@nibio.no>)
Responses Re: PostgreSQL and a Catch-22 Issue related to dead rows
List pgsql-performance
On Mon, Dec 9, 2024 at 6:03 AM Lars Aksel Opsahl <Lars.Opsahl@nibio.no> wrote:
In one case, we processed a total of 750 cells, with an overall runtime of 40 hours. However, one specific cell took over 12 hours to complete, most of which was spent on removing small areas by deleting edges in PostGIS Topology. The root cause of this delay is related to removal of dead rows.
Can you please expand exactly what you mean by "removal of dead rows" here, and what the exact issue you are facing is?
By introducing periodic COMMIT statements and VACUUM (FULL) operations
Vacfull is a pretty rough solution, and almost always not the correct tool for the job, IMHO.

Yes there are very good reason for the way removal for dead rows work now, but is there any chance of adding an option when creating table to disable this behavior for instance for unlogged tables ?

It's still not clear exactly what the ask is here, but there is little chance we would design an alternative MVCC system just to accommodate this use case.

Cheers,
Greg

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