Re: PATCH: Batch/pipelining support for libpq

On Tue, Mar 14, 2017 at 5:50 PM, Vaishnavi Prabakaran <
vaishnaviprabakaran(at)gmail(dot)com> wrote:

>
>
> On Tue, Mar 14, 2017 at 4:19 AM, Daniel Verite <daniel(at)manitou-mail(dot)org>
> wrote:
>
>>
>> I mean the next iteration of the above while statement. Referring
>> to the doc, that would be the "next batch entry":
>>
>> " To get the result of the first batch entry the client must call
>> PQbatchQueueProcess. It must then call PQgetResult and handle the
>> results until PQgetResult returns null (or would return null if
>> called). The result from the next batch entry may then be retrieved
>> using PQbatchQueueProcess and the cycle repeated"
>>
>> Attached is a bare-bones testcase showing the problem.
>> As it is, it works, retrieving results for three "SELECT 1"
>> in the same batch. Now in order to use the single-row
>> fetch mode, consider adding this:
>>
>> r = PQsetSingleRowMode(conn);
>> if (r!=1) {
>> fprintf(stderr, "PQsetSingleRowMode() failed for i=%d\n", i);
>> }
>>
>> When inserted after the call to PQbatchQueueProcess,
>> which is what I understand you're saying works for you,
>> it fails for me when starting to get the results of the 2nd query
>> and after.
>>
>>
>
> Thanks for explaining the issue in detail and yes, I do see the issue
> using your attached test file.
>
> And I think the problem is with the "parseInput" call at the end of
> PQbatchQueueProcess().
> I don't see the need for "parseInput" to cover the scope of
> PQbatchQueueProcess(), also anyways we do it in PQgetResult().
> This function call changes the asyncstatus of connection to
> READY(following command complete message from backend), so eventually
> PQsetSingleRowMode() is failing. So, attached the alternative fix for this
> issue.
>
Please share me your thoughts.
>
> I would also like to hear Craig's opinion on it before applying this fix
> to the original patch, just to make sure am not missing anything here.
>
>
Attached the code patch applied with the fix explained above and moving the
CF status seeking review.

Thanks & Regards,
Vaishnavi,
Fujitsu Australia.