Re: SQL compatibility reminder: MySQL vs PostgreSQL

On 2010-03-08 11:47 +0200, Pierre C wrote:
>> As far as I can tell, we already do index skip scans:
> 
> This feature is great but I was thinking about something else, like SELECT  
> DISTINCT, which currently does a seq scan, even if x is indexed.
> 
> Here is an example. In both cases it could use the index to skip all  
> non-interesting rows, pulling only 69 rows from the heap instead of 120K.

Oh, this is what I believe MySQL calls "loose index scans".  I'm
actually looking into this as we speak, but there seems to be a
non-trivial amount of work to be done in order for this to work.


Regards,
Marko Tiikkaja