Re: PostgreSQL clustering VS MySQL clustering - Mailing list pgsql-performance

From Greg Stark
Subject Re: PostgreSQL clustering VS MySQL clustering
Date
Msg-id 87brbh753e.fsf@stark.xeocode.com
Whole thread Raw
In response to PostgreSQL clustering VS MySQL clustering  (Dawid Kuroczko <qnex42@gmail.com>)
Responses Re: PostgreSQL clustering VS MySQL clustering  ("Jim C. Nasby" <decibel@decibel.org>)
List pgsql-performance
Dawid Kuroczko <qnex42@gmail.com> writes:

> Quick thought -- would it be to possible to implement a 'partial VACUUM'
> per analogiam to partial indexes?

No.

But it gave me another idea. Perhaps equally infeasible, but I don't see why.

What if there were a map of modified pages. So every time any tuple was marked
deleted it could be marked in the map as modified. VACUUM would only have to
look at these pages. And if it could mark as free every tuple that was marked
as deleted then it could unmark the page.

The only downside I see is that this could be a source of contention on
multi-processor machines running lots of concurrent update/deletes.

--
greg

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