Re: Foreign join pushdown vs EvalPlanQual - Mailing list pgsql-hackers

From Etsuro Fujita
Subject Re: Foreign join pushdown vs EvalPlanQual
Date
Msg-id 5657ECAD.5080603@lab.ntt.co.jp
Whole thread Raw
In response to Re: Foreign join pushdown vs EvalPlanQual  (Kouhei Kaigai <kaigai@ak.jp.nec.com>)
Responses Re: Foreign join pushdown vs EvalPlanQual  (Kouhei Kaigai <kaigai@ak.jp.nec.com>)
List pgsql-hackers
On 2015/11/27 0:14, Kouhei Kaigai wrote:

>> The documentation says as following so I think the former has.
>>
>> # I don't understhad what 'can or must' means, though... 'can and
>> # must'?
>>
>> +     Also, this callback can or must recheck scan qualifiers and join
>> +     conditions which are pushed down. Especially, it needs special

> If fdw_recheck_quals is set up correctly and join type is inner join,
> FDW driver does not recheck by itself. Elsewhere, it has to recheck
> the joined tuple, not only reconstruction.

Sorry, I don't understand this.  In my understanding, fdw_recheck_quals
can be defined for a foreign join, regardless of the join type, and when
the fdw_recheck_quals are defined, the RecheckForeignScan callback
routine doesn't need to evaluate the fdw_recheck_quals by itself.  No?

Best regards,
Etsuro Fujita




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