Excerpts from Bruce Momjian's message of dom ago 22 12:51:47 -0400 2010:
> Well, the reason that value is 200 million is for pg_clog cleanup, not
> for xid wraparound protection. The next sentence does relate to xid
> wraparound, but it seems to fit because the previous sentence ends with
> xid wraparound:
>
> Note that the system will launch autovacuum processes to
> prevent wraparound even when autovacuum is otherwise disabled.
>
> If we were worried about just xid wraparound I assume the value would be
> 2 billion.
>
> Do you have a suggestion? Reorder the items?
I'd add another para before that one saying that this value "also"
affects pg_clog truncation. I agree that putting pg_clog truncation as
the first item here is not an improvement. For most people, having
those pg_clog files there or not is going to be a wash, compared to data
size.
--
Álvaro Herrera <alvherre@commandprompt.com>
The PostgreSQL Company - Command Prompt, Inc.
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