Hi, Alexander!
On Oct 12, Alexander Barkov wrote:
> >> diff --git a/sql/field.cc b/sql/field.cc
> >> index 46a3a1deea3..fc3456e2ccb 100644
> >> --- a/sql/field.cc
> >> +++ b/sql/field.cc
> >> @@ -7368,7 +7368,9 @@ bool
> >> Field_longstr::cmp_to_string_with_same_collation(const Item_bool_func
> >> *cond,
> >> const Item *item) const
> >> {
> >> + Type_handler_hybrid_field_type cmp(type_handler_for_comparison());
> >
> > Can this be anything else but type_handler_long_blob ?
> > if not, then I'd suggest
> >
> > Type_handler_hybrid_field_type cmp(type_handler_long_blob);
> > DBUG_ASSERT(type_handler_for_comparison() == &type_handler_long_blob);
>
> Generally we don't know. It's now for every single plugin to decide.
> One can make a plugin using Field_longstr as a base for its Field,
> but with a different comparison type handler.
>
> I wrote it in a generic way which should work for all cases.
Yes, I know. But practically we won't have such plugins for quite a
while, so I'd rather prefer a shorter execution path and a faster code.
And an assert that will remind us to implement your gneralized approach
when the assumption will be broken.
> > One more question. What type do we have where you need to aggregate here
> > and simple
> >
> > item->type_handler_for_comparison() != &type_handler_long_blob
> >
> > won't do?
>
> We don't know. It's for a plugin to decide if its data type
> is stronger of weaker than CHAR/VARCHAR/TEXT.
> For INET6 and UUID we decided they are stronger.
> But eventually we may want to add some weaker data type.
Same here.
Regards,
Sergei
VP of MariaDB Server Engineering
and secur...@mariadb.org
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