Re: Review: Display number of changed rows since last analyze

On Mon, Jun 17, 2013 at 1:49 PM, Albe Laurenz <laurenz.albe@wien.gv.at> wrote:
> This is a review of the patch in 5192D7D2.8020605@catalyst.net.nz
>
> The patch applies cleanly (with the exception of catversion.h of course),
> compiles without warnings and passes the regression tests.
>
> It contains enough documentation, though I'd prefer
> "Estimated number of rows modified since the table was last analyzed"
> to
> "Estimated number of row changes (inserts + updates + deletes) since the last analyze"
>
> The patch works as it should, and I think that this is a
> useful addition.  It only exposes a value that is already
> available internally, so there shouldn't be any penalties.
>
> I think that the column name is ok as it is, even if it
> is a bit long - I cannot come up with a more succinct
> idea.  Perhaps "n_changed_since_analyze" could be shortened
> to "n_mod_since_analyze", but that's not much of an improvement.

AFAICT it's related to "n_live_tup", and "n_dead_tup". How about just
"n_mod_tup"? Though that doesn't convey that it's since the last
analyze, I guess.

But given that both n_dead_tup and n_live_tup don't really indicate
that they're not "since the beginning of stats" in the name (which
other stats counters are), I'm not sure that's a problem? It would be
a name that sounds more similar to the rest of the table.


--Magnus HaganderMe: http://www.hagander.net/Work: http://www.redpill-linpro.com/