Statistics and Group by's

[Liam1]

Hello,

Is there a large benfit to be had collecting Stats on Group by columns.

If so, can I use a composed stats (Field_1, Field_2 etc)?

I don't want to create an INDEX unless necessary - I doubt this would even help?

I do this insert and group by 11 times due to spool issues, and our databse is running so slow at the minute I cannot test it!

Thanks,

Liam.

 

[dnoeth]

It's the best to have stats on the group by columns without any additional columns.

Those stats won't make the aggregate step run faster, but the optimizer knows better about the expected number of rows, so there maybe a different/better plan with stats.

Dieter