Re: [Ruby-DBI-devel] PGconn::exec vs. PGconn::async_exec benchmark

[Florian G\. P. <fg...@ph...>]

Hi

sorry to reply to my own message - but after thinking a bit, I came to the
conclusion that there might be a noticeable performance penality for a lot
of very fast selects (or inserts, but I guess selects are much faster than
inserts in general).

This is due to the fact that the pseudo-asynchronous functions always
activate the scheduler at least once (when doing rb_thread_select), and I
guess this means that they have to wait for other threads to do their work
(if there are non-blocked other threads) before they can continue.

This might be what a user wants (if the other threads maintain a gui, this
is most certainly what the user wants), but in some cases one might prefer
the "traditional" behaviour. 

So, maybe the most elegant way is to introduct a parameter to the
query-executing functions which lets the user decide what behaviour he
prefers. I would still suggest to make the pseudo-asynchronous behaviour the
default, since in most cases it won't have noticeable disadvantages, but
very noticeable advantages.

Greetings, Florian Pflug