Re: Index Skip Scan

El 13/09/18 a las 18:39, Jesper Pedersen escribió:
>
> Yes, this doesn't look good. Using your test case I'm seeing that 
> unique is being chosen when the group size is below 34, and skip 
> above. This is with the standard initdb configuration; did you change 
> something else ? Or did you force the default plan ?

Sorry I didn't mention this, the first column is indeed forced skip 
scan, just to see how it compares to index scan.

> This is something to look at -- maybe there is a way to use 
> btpo_next/btpo_prev instead/too in order to speed things up. Atm we 
> just have the scan key in BTScanOpaqueData. I'll take a look after my 
> upcoming vacation; feel free to contribute those changes in the 
> meantime of course.
>

I probably won't be able to contribute the changes, but I'll try to 
review them.

-- 
Alexander Kuzmenkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company