Re: Stats not updated after rollback -- autovacuum confused.

This has been saved for the 8.4 release:

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Dawid Kuroczko wrote:
> Hello, I have a system where there are mostly COPYs,
> which insert data into a table. Ocasionally a COPY will fail (and thus,
> dead rows appear), but as far as I can tell ROLLBACK is not reflected
> anywhere in the pg_stats_user_tables. And since there are no rows
> n_tup_upd or n_tup_del, therefore autovacuum will not fire for that table.
>
> I see two possible solutions:
> 1) let rollback increment both n_tup_ins and n_tup_del (or maybe
> n_tup_upd, at least)? This would be a good safeguard, I guess.
>
> 2) ANALYZE is able to see wether table is accumulating dead rows.
> It might be a good idea to make ANALYZE able hint autovacuum that
> some tables need VACUUM (that they exceed limits set for autovacuum).
>
> The 2nd point could be a TODO item, perhaps? Something like:
> When ANALYZE runs, make it note removable dead rows and non-removable
> dead rows. If removable dead rows exceed some threshold, hint autovacuum
> at that table.
>
> Regards,
> Dawid
>
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