Re: [Firebird-devel] UPDATE OR INSERT and NULLS

[Adriano d. S. F. <adr...@uo...>]

Dmitry Yemanov wrote:
> Adriano dos Santos Fernandes wrote:
>   
>> I see no problem, but if there is any benefit maybe this could be a job 
>> to the optimizer.
>>     
>
> I'm not sure I understand you. The optimizer cannot generate BLR and I 
> doubt it should be so smart to replace the parsed nod_equal with 
> nod_equiv :-)
I mean, in no-MATCHING case, fields of the boolean is from a PK, hence 
they're not NULLable.
I don't see difference of nod_equiv and not_equal in this context, maybe 
some cycles more in nod_equiv.

In this case, as the optimizer is smart enough to choose an index when 
you do "where field = something", it can see "field" is not nullable and 
transform nod_equiv to nod_equal.

Or I'm missing something?


Adriano