Re: db stats vs table stats

Oops, typo:  I reversed the inequality.  I've corrected it below.

On Friday February 23 2007 2:02 pm, Ed L. wrote:
> I've been periodically collecting the stats stored in
> pg_statio_all_tables and pg_stat_database for ~30 different
> clusters, and have noticed a curiosity.
>
> I would have thought that for a given period, the change in
> pg_stat_database.blks_read would be >= the sum of the changes
> in pg_statio_user_tables.heap_blks_read +
> pg_statio_user_tables.idx_blks_read +
> pg_statio_user_tables.toast_blks_read +
> pg_statio_user_tables.tidx_blks_read.
>
> In short, the total would be >= heap + idx + toast + idx for
> user tables.
>
> It does not appear that way.  The table-level IO stats appear
> to be typically 1-2 orders of magnitude larger than the
> db-level stats.  Can anyone explain that?
>
> TIA.
> Ed