[TS-2458] The http transaction should not be rescheduled when the original connections overflow

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Component/s: HTTP
• Assignee: Unassigned
• Reporter: Yu Qing
• Created: 30/Dec/13 06:27
• Updated: 16/Aug/16 16:04
• Resolved: 16/Aug/16 16:04

Description

we have origin connections limits, the parameter proxy.config.http.server_max_connections is for whole connections, and the parameter proxy.config.http.origin_max_connections is for the specified connections per original server ip / host.

the http transaction is rescheduled / retried after 100ms when it's original connections exceed these limits.

these transactions will be rescheduled repeatly when the original server is very slow. the system worsens when these retries happen because the http transactions accumulate more and more.

I think we should cut off these transactions immediately other than retry after 100ms.

the rescheduling codes in proxy/http/HttpSM.cc as:

4581     if (sum >= t_state.http_config_param->server_max_connections) {
4582       ink_assert(pending_action == NULL);
4583       pending_action = eventProcessor.schedule_in(this, HRTIME_MSECONDS(100));
4584       httpSessionManager.purge_keepalives();
4585       return;
4586     }
4587   }
4588   // Check to see if we have reached the max number of connections on this
4589   // host.
4590   if (t_state.txn_conf->origin_max_connections > 0) {
4591     ConnectionCount *connections = ConnectionCount::getInstance();
4592 
4593     char addrbuf[INET6_ADDRSTRLEN];
4594     if (connections->getCount((t_state.current.server->addr)) >= t_state.txn_conf->origin_max_connections) {
4595       DebugSM("http", "[%" PRId64 "] over the number of connection for this host: %s", sm_id,
4596         ats_ip_ntop(&t_state.current.server->addr.sa, addrbuf, sizeof(addrbuf)));
4597       ink_assert(pending_action == NULL);
4598       pending_action = eventProcessor.schedule_in(this, HRTIME_MSECONDS(100));
4599       return;
4600     }
4601   }

Issue Links

• is depended upon by: TS-3313 New World order for connection management and timeouts