Re: Use extended statistics to estimate (Var op Var) clauses

[Mark Dilger]

> On Aug 11, 2021, at 3:45 PM, Tomas Vondra <tomas.von...@enterprisedb.com> 
> wrote:
> 
> As I said in my last reply, I'm not sure it's particularly useful to look at 
> overall results from data sets with independent columns. That's not what 
> extended statistics are for, and people should not create them in those cases 
> ...

We sent our last emails more or less simultaneously.  I'm not ignoring your 
email; I just hadn't seen it yet when I sent mine.

> Maybe it'd be better to focus on cases with the largest difference in 
> estimates, and investigate those more closely.

Yeah, I'm working on a correlated stats test as I write this.  I'll get back to 
you when I have results.

—
Mark Dilger
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company