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