Re: Queries taking ages in PG 8.1, have been much faster in PG<=8.0

> -----Ursprüngliche Nachricht-----
> Von: Tom Lane [mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us]
> Gesendet: Montag, 5. Dezember 2005 15:33
> An: Markus Wollny
> Cc: pgsql-performance(at)postgresql(dot)org
> Betreff: Re: AW: [PERFORM] Queries taking ages in PG 8.1,
> have been much faster in PG<=8.0

> Could we see the pg_stats row for answer.session_id in both
> 8.0 and 8.1?

Here you are:

select null_frac
, avg_width
, n_distinct
, most_common_vals
, most_common_freqs
, histogram_bounds
, Correlation
from pg_stats
where schemaname = 'survey'
and tablename = 'answer'
and attname = 'session_id';

8.1:
null_frac 0
avg_width 4
n_distinct 33513
most_common_vals {1013854,1017890,1021551,1098817,764249,766938,776353,780954,782232,785985}
most_common_freqs {0.001,0.001,0.001,0.001,0.000666667,0.000666667,0.000666667,0.000666667,0.000666667,0.000666667}
histogram_bounds {757532,819803,874935,938170,1014421,1081507,1164659,1237281,1288267,1331016,1368939}
Correlation -0.0736492

8.0.3:
null_frac 0
avg_width 4
n_distinct 29287
most_common_vals {765411,931762,983933,1180453,1181959,1229963,1280249,1288736,1314970,764901}
most_common_freqs {0.001,0.001,0.001,0.001,0.001,0.001,0.001,0.001,0.001,0.000666667}
histogram_bounds {757339,822949,875834,939085,1004782,1065251,1140682,1218336,1270024,1312170,1353082}
Correlation -0.237136

Kind regards

Markus