On 2013/8/1 17:05, Godbach wrote:
> Hi Willy,
>
> Haproxy will check the number of concurrent sessions assigned to the
> server after being selected from lb trees. Both leastconn and roundrobin
> use the same condition as below:
>
> fwlc_get_next_server():
> if (!s->maxconn || (!s->nbpend && s->served < srv_dynamic_maxconn(s))) {
> if (s != srvtoavoid) {
> srv = s;
> break;
> }
> avoided = s;
> }
>
> fwrr_get_next_server():
> if (!srv->maxconn || (!srv->nbpend && srv->served <
> srv_dynamic_maxconn(srv))) {
> /* make sure it is not the server we are trying to exclude... */
> if (srv != srvtoavoid || avoided)
> break;
>
> avoided = srv; /* ...but remember that is was selected yet avoided */
> }
>
> It means that the server will not be used if there are sessions in
> pending queue or srv->served exceeds the dynamic maxconn of server with
> srv->maxconn set.
>
> But static-rr ignores the sessions in pending queue and just uses
> srv->cur_sess to compare with dynamic maxconn ad below:
>
> map_get_server_rr():
> if (!srv->maxconn || srv->cur_sess < srv_dynamic_maxconn(srv)) {
> /* make sure it is not the server we are try to exclude... */
> if (srv != srvtoavoid) {
> px->lbprm.map.rr_idx = newidx;
> return srv;
> }
>
> avoided = srv; /* ...but remember that is was selected yet avoided */
> avoididx = newidx;
> }
>
> So I am wondering that if there is something intentionally to use
> different check condition that I have not caught.
>
Hi Willy,
It seems that static-rr should also use the same check condition for the
server after being selected as roundrobin and leastconn as below:
if (!srv->maxconn || (!srv->nbpend && srv->served <
srv_dynamic_maxconn(srv)))
not the following:
if (!srv->maxconn || srv->cur_sess < srv_dynamic_maxconn(srv)) {
--
Best Regards,
Godbach
