Re: Fix gin index cost estimation

Le vendredi 2 décembre 2022, 12:33:33 CET Alexander Korotkov a écrit :
> Hi, Ronan!
> Thank you for your patch.  Couple of quick questions.
> 1) What magic number 50.0 stands for?  I think we at least should make
> it a macro.

This is what is used in other tree-descending  estimation functions, so I used 
that too. Maybe a DEFAULT_PAGE_CPU_COST macro would work for both ? If so I'll 
separate this into two patches, one introducing the macro for the other 
estimation functions, and this patch for gin.

> 2) "We only charge one data page for the startup cost" – should this
> be dependent on number of search entries?

Good point, multiplying it by the number of search entries would do the trick. 

Thank you for looking at this !

Regards,

--
Ronan Dunklau