2011/5/24 Tom Lane <tgl@sss.pgh.pa.us>:
> Hitoshi Harada <umi.tanuki@gmail.com> writes:
>> It looks to me like mergejoin_allowed should be initialized to false.
>> If enable_mergejoin is off and jointype != JOIN_FULL then mergejoin is
>> not allowed, isn't it? Sorry for noise if it's only my confusing.
>
> No, the code is correct as-is: we need the flag to be set true by
> default, because the way that the function is using it, we'll also skip
> some nestloop possibilities when it's false. Note the comment for step
> 2.
>
> It could be that a different name for that flag variable would be a
> better idea, but neither Robert nor I could come up with a better one.
Ah, ok. I think I now understand it. "mergejoin_doable" flag. Thanks.
Regards,
--
Hitoshi Harada
