Tom Lane wrote:
Alban Hertroys <alban@xxxxxxxxxxxxxxxxx> writes:
However, mm_product.number always matches either mm_insrel.snumber or
mm_insrel.dnumber (source and destination respectively). The other way
around this isn't the case; then snumber and dnumber match number-fields
in other tables (they always do).
Oh, then we are looking at the wrong things: we should be comparing the
histograms of the fields that are being used as the join keys in this
query. I had thought they were both "number", but I must be confused.
The design is certainly a bit confusing until you get used to it. It
usually takes new devs here a while to find their way around MMBase
(www.mmbase.org) and its peculiarities. It doesn't help that the
documentation is in rather bad English.
regards, tom lane
So this is what we're looking for, right? I can't say I understand how
to interpret this, let alone come to conclusions. I'm afraid I totally
depend on your interpretation here...
zorgweb_solaris=> select * from pg_stats where (attname in ('snumber',
'dnumber') and tablename = 'mm_insrel_table') or (attname = 'number' and
tablename = 'mm_product_table');
-[ RECORD 1
]-----+-----------------------------------------------------------------------------------------------------------
schemaname | public
tablename | mm_product_table
attname | number
null_frac | 0
avg_width | 4
n_distinct | -1
most_common_vals |
most_common_freqs |
histogram_bounds | {2930,3244,3558,3872,4186,4500,4814,5128,5442,5756,6070}
correlation | 0.993398
-[ RECORD 2
]-----+-----------------------------------------------------------------------------------------------------------
schemaname | public
tablename | mm_insrel_table
attname | snumber
null_frac | 0
avg_width | 4
n_distinct | 14336
most_common_vals | {4300,5210,5366,2994,3724,4118,2982,3058,3072,3460}
most_common_freqs |
{0.00266667,0.002,0.002,0.00166667,0.00166667,0.00166667,0.00133333,0.00133333,0.00133333,0.00133333}
histogram_bounds |
{135,3768,4780,14822,57048,92958,125442,158954,433002,502836,610034}
correlation | 0.083602
-[ RECORD 3
]-----+-----------------------------------------------------------------------------------------------------------
schemaname | public
tablename | mm_insrel_table
attname | dnumber
null_frac | 0
avg_width | 4
n_distinct | 11028
most_common_vals | {1117583,279,415,291,343,389,635,839,1043,319}
most_common_freqs |
{0.00433333,0.00333333,0.003,0.00266667,0.00266667,0.00266667,0.00266667,0.00266667,0.00266667,0.00233333}
histogram_bounds |
{147,717,3770,263126,327054,429524,461026,490094,518872,544098,1117603}
correlation | 0.0571927
Regards,
--
Alban Hertroys
alban@xxxxxxxxxxxxxxxxx
magproductions b.v.
T: ++31(0)534346874
F: ++31(0)534346876
M:
I: www.magproductions.nl
A: Postbus 416
7500 AK Enschede
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