Re: BUG #8681: column 'n_tup_del' of pg_stat_user_tables doesn't change in case of truncate - Mailing list pgsql-bugs

From Rod Taylor
Subject Re: BUG #8681: column 'n_tup_del' of pg_stat_user_tables doesn't change in case of truncate
Date
Msg-id CAKddOFAOJnDLM-Jde=Y_k8QK6GLVJk1fe_EQRGnYK-42zEH=5A@mail.gmail.com
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In response to Re: BUG #8681: column 'n_tup_del' of pg_stat_user_tables doesn't change in case of truncate  (Stephen Frost <sfrost@snowman.net>)
Responses Re: BUG #8681: column 'n_tup_del' of pg_stat_user_tables doesn't change in case of truncate  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-bugs
It's still an interesting question.

Why doesn't truncate reset table statistic to 0? The table state prior to a
truncate shouldn't influence vacuum or necessity after the truncate.

Not that vacuuming a recently truncated table would be expensive, but
Analyze timing is a concern.

regards,

Rod



On Mon, Dec 16, 2013 at 10:50 AM, Stephen Frost <sfrost@snowman.net> wrote:

> Anit,
>
> * Anit Chakkarwar (anitchakkarwar@gmail.com) wrote:
> > Now n_tup_del = 2, n_tup_ins=120, n_live_tup=20 in pg_stat_user_tables,
> but
> > how can I figure out what has happened to 98 rows?
>
> This is information for statistics- if you need an accurate count,
> you'll need to use a trigger and track that information explicitly..
> There can be other ways that n_tup_del can end up being inexact.
>
>         Thanks,
>
>                 Stephen
>

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