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[Sergey Petrunia <sergey@xxxxxxxxxxx>]

On Sat, Feb 13, 2021 at 03:23:50PM +0300, Sergey Petrunia wrote:
> >  /* Substituting WHERE clause's field items with sort-nest's field items */
> >  if (conds)
> >  {
> >    conds= conds->transform(thd, &Item::replace_with_nest_items, TRUE,
> >                            (uchar *) nest_info);
> >    conds->update_used_tables();
> >  }
> 
> As far as I understand, the items from the WHERE clause can be attached both
> outside and inside the nest.
> 
> Moreover, if the WHERE clause has this form
> 
>  (condA(t1) AND condB(t2) OR (condC(t1) AND condD(t2)) 
> 
> and the join order is t1,t2, then make_cond_for_table() will attach
> condA(t1) to both t1 and t2.
> 
> How is this handled?

Ah, I've found extract_condition_for_the_nest() function.
This is now cleara.

BR
 Sergei
-- 
Sergei Petrunia, Software Developer
MariaDB Corporation | Skype: sergefp | Blog: http://petrunia.net