Re: PATCH: Batch/pipelining support for libpq

On Mon, May 23, 2016 at 8:50 AM, Andres Freund <andres@anarazel.de> wrote:
> On 2016-05-23 17:19:09 +0800, Craig Ringer wrote:
>> Following on from the foreign table batch inserts thread[1], here's a patch
>> to add support for pipelining queries into asynchronous batches in libpq.
>
> Yay!
>> I'm measuring 300x (not %) performance improvements doing batches on
>> servers over the Internet, so this seems pretty worthwhile. It turned out
>> to be way less invasive than I expected too.
>
> yay^2.

I'll follow this mood. Yeha.

>> (I intentionally didn't add any way for clients to annotate each work-item
>> in a batch with their own private data. I think that'd be really useful and
>> would make implementing clients easier, but should be a separate patch).
>>
>> This should be very useful for optimising FDWs, Postgres-XC, etc.
>
> And optimizing normal clients.
>
> Not easy, but I'd be very curious how much psql's performance improves
> when replaying a .sql style dump, and replaying from a !tty fd, after
> hacking it up to use the batch API.

Did you consider the use of simple_list.c instead of introducing a new
mimic as PGcommandQueueEntry? It would be cool avoiding adding new
list emulations on frontends.
-- 
Michael