Re: Flushing large data immediately in pqcomm

On Thu, 21 Mar 2024 at 13:24, Melih Mutlu <m(dot)melihmutlu(at)gmail(dot)com> wrote:
> What if I do a simple comparison like PqSendStart == PqSendPointer instead of calling pq_is_send_pending() as Heikki suggested, then this check should not hurt that much. Right? Does that make sense?

As I understand the code, there's no problem calling
internal_flush_buffer() when the buffer is empty and I suspect that if
we're sending a few buffers with "len > PqSendBufferSize" that it's
just so unlikely that the buffer is empty that we should just do the
function call and let internal_flush_buffer() handle doing nothing if
the buffer really is empty. I think the chances of
internal_flush_buffer() having to do exactly nothing here is less than
1 in 8192, so I just don't think the check is worthwhile. The reason
I don't think the odds are exactly 1 in 8192 is because if we're
sending a large number of bytes then it will be common that the buffer
will contain exactly 5 bytes due to the previous flush and command
prefix just having been added.

It's worth testing both, however. I might be wrong. Performance is
hard to predict. It would be good to see your test.sh script run with
and without the PqSendStart == PqSendPointer condition.

David