Re: multivariate statistics (v19)

On 01/30/2017 09:37 PM, Alvaro Herrera wrote:
> Tomas Vondra wrote:
>
>> The 'built' flags may be easily replaced with a check if the bytea-like
>> columns are NULL, and the 'enabled' columns may be replaced by the array of
>> char, just like you proposed.
>>
>> That'd give us a single catalog looking like this:
>>
>> pg_mv_statistics
>> starelid
>> staname
>> stanamespace
>> staowner -- all the above as currently
>> staenabled array of "char" {d,f,s}
>> stakeys
>> stadeps (dependencies)
>> standist (ndistinct coefficients)
>> stamcv (MCV list)
>> stahist (histogram)
>>
>> Which is probably a better / simpler structure than the current one.
>
> Looks good to me. I don't think we need to keep the names very short --
> I would propose "standistinct", "stahistogram", "stadependencies".
>

Yeah, I got annoyed by the short names too.

This however reminds me that perhaps pg_mv_statistic is not the best
name. I know others proposed pg_statistic_ext (and pg_stats_ext), and
while I wasn't a big fan initially, I think it's a better name. People
generally don't know what 'multivariate' means, while 'extended' is
better known (e.g. because Oracle uses it for similar stuff).

So I think I'll switch to that name too.

regards

--
Tomas Vondra http://www.2ndQuadrant.com
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