Re: unnest-like pg_stats.most_common_values and pg_stats.most_common_freqs

On Fri, Nov 17, 2017 at 09:32:23PM +0100, Luca Ferrari wrote:
> Hi all,
> maybe this is trivial, but I need an hint on a way to see a table form
> of the MCVs and MCFs out of pg_stats with a query. Is it possible to
> get a set of rows each with a most common value on one column and the
> corresponding column on the the other? (assuming I can cast the array
> of MCVs to the right type array)

I think you want something like this ?

postgres=# SELECT schemaname, tablename, attname, unnest(histogram_bounds::text::text[]), histogram_bounds FROM pg_stats LIMIT 9;
pg_catalog | pg_pltemplate | tmplname | plperl | {plperl,plperlu,plpgsql,plpython2u,plpython3u,plpythonu,pltcl,pltclu}
pg_catalog | pg_pltemplate | tmplname | plperlu | {plperl,plperlu,plpgsql,plpython2u,plpython3u,plpythonu,pltcl,pltclu}
pg_catalog | pg_pltemplate | tmplname | plpgsql | {plperl,plperlu,plpgsql,plpython2u,plpython3u,plpythonu,pltcl,pltclu}
pg_catalog | pg_pltemplate | tmplname | plpython2u | {plperl,plperlu,plpgsql,plpython2u,plpython3u,plpythonu,pltcl,pltclu}
pg_catalog | pg_pltemplate | tmplname | plpython3u | {plperl,plperlu,plpgsql,plpython2u,plpython3u,plpythonu,pltcl,pltclu}
pg_catalog | pg_pltemplate | tmplname | plpythonu | {plperl,plperlu,plpgsql,plpython2u,plpython3u,plpythonu,pltcl,pltclu}
pg_catalog | pg_pltemplate | tmplname | pltcl | {plperl,plperlu,plpgsql,plpython2u,plpython3u,plpythonu,pltcl,pltclu}
pg_catalog | pg_pltemplate | tmplname | pltclu | {plperl,plperlu,plpgsql,plpython2u,plpython3u,plpythonu,pltcl,pltclu}
pg_catalog | pg_pltemplate | tmplhandler | plperl_call_handler | {plperl_call_handler,plperlu_call_handler,plpgsql_call_handler,plpython2_call_handler,plpython3_call_handler,plpython_call_handler,pltcl_cal
l_handler,pltclu_call_handler}

Justin