I am looking a bit more seriously at this patch and assigned myself as a reviewer.
Much appreciated.
testlibpqbatch.c:1239:73: warning: format specifies type 'long' but the argument has type '__darwin_suseconds_t' (aka 'int') [-Wformat] printf("batch insert elapsed: %ld.%06lds\n", elapsed_time.tv_sec, elapsed_time.tv_usec); macos complains here. You may want to replace %06lds by just %06d.
Yeah, or cast to a type known to be big enough. Will amend.
This patch generates a core dump, use for example pg_ctl start -w and you'll bump into the trace above. There is something wrong with the queue handling.
Huh. I didn't see that here (Fedora 23). I'll look more closely.
Do you have plans for a more generic structure for the command queue list?
No plans, no. This was a weekend experiment that turned into a useful patch and I'm having to scrape up time for it amongst much more important things like logical failover / sequence decoding and various other replication work.
Thanks for the docs review too, will amend.
+ fprintf(stderr, "internal error, COPY in batch mode"); + abort(); I don't think that's a good idea. defaultNoticeProcessor can be overridden to allow applications to have error messages sent elsewhere. Error messages should also use libpq_gettext, and perhaps be stored in conn->errorMessage as we do so for OOMs happening on client-side and reporting them back even if they are not expected (those are blocked PQsendQueryStart in your patch).
src/test/examples is a good idea to show people what this new API can do, but this is never getting compiled. It could as well be possible to include tests in src/test/modules/, in the same shape as what postgres_fdw is doing by connecting to itself and link it to libpq. As this patch complicates quote a lot fe-exec.c, I think that this would be worth it. Thoughts?
I didn't think it added much complexity to fe-exec.c personally. A lot of the appeal is that it has very minor impact on anything that isn't using it.
I think it makes sense to (ab)use the recovery module tests for this, invoking the test program from there.
Ideally I'd like to teach pgsql and pg_restore how to use async mode, but that's a whole separate patch.
