Re: [PERFORM] best statistic target for boolean columns

[Gaetano Mendola]

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Josh Berkus wrote:
| Gaetano,
|
|
|>don't you think the best statistic target for a boolean
|>column is something like 2?  Or in general the is useless
|>have a statistics target > data type cardinality ?
|
|
| It depends, really, on the proportionality of the boolean values; if they're
| about equal, I certainly wouldn't raise Stats from the default of 10.   If,
| however, it's very dispraportionate -- like 2% true and 98% false -- then it
| may pay to have better statistics so that the planner doesn't assume 50%
| hits, which it otherwise might.
So, I didn't understand how the statistics hystogram works.
I'm going to take a look at analyze.c
Regards
Gaetano Mendola
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