| From: | Tomas Vondra <tomas(dot)vondra(at)enterprisedb(dot)com> |
|---|---|
| To: | Mark Dilger <mark(dot)dilger(at)enterprisedb(dot)com> |
| Cc: | Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Use extended statistics to estimate (Var op Var) clauses |
| Date: | 2021-08-11 23:06:57 |
| Message-ID: | a1e2cd55-0028-06ff-28fe-036f9b3b830d@enterprisedb.com |
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| Lists: | pgsql-hackers |
On 8/12/21 12:48 AM, Mark Dilger wrote:
>
>
>> On Aug 11, 2021, at 3:45 PM, Tomas Vondra
>> <tomas(dot)vondra(at)enterprisedb(dot)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.
>
Apologies, I didn't mean to imply you're ignoring my messages.
>> 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.
>
Cool, thanks!
regards
--
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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