Re: Index Skip Scan

Hi Pavel,

On 10/9/18 9:42 AM, Pavel Stehule wrote:
> I tested last patch and I have some notes:
> 
> 1.
> 
> postgres=# explain select distinct a10000 from foo;
> +-------------------------------------------------------------------------------------------+
> |                                        QUERY PLAN                                         |
> +-------------------------------------------------------------------------------------------+
> | Unique  (cost=0.43..4367.56 rows=9983 width=4)                                            |
> |   ->  Index Skip Scan using foo_a10000_idx on foo  (cost=0.43..4342.60 rows=9983 width=4) |
> +-------------------------------------------------------------------------------------------+
> (2 rows)
> 
> In this case Unique node is useless and can be removed
> 
> 2. Can be nice COUNT(DISTINCT support) similarly like MIN, MAX suppport
> 
> 3. Once time patched postgres crashed, but I am not able to reproduce it.
>

Please, send that query through if you can replicate it. The patch 
currently passes an assert'ed check-world, so your query clearly 
triggered something that isn't covered yet.

> Looks like very interesting patch, and important for some BI platforms
> 

Thanks for your review !

Best regards,
  Jesper