LS server running out of memory

[giuseppe.corti]

Hi Kevin,

Please note that a new connection does not always mean new client. Sometimes, especially for no webscoket case, clients already connected may require a new connection (for a rebind, or a polling request or a new subscription).
Thus limiting the number of connections can affect the proper functioning of sessions also already established.

The parameters that protect the server from your critical situation are:
<server_pool_max_queue>100</server_pool_max_queue><br /> <handshake_pool_max_queue>100</handshake_pool_max_queue>
and in your specific case it seems that the second might work.
However, for a typical DoS attack scenario, we expect that the firewall should actually apply the necessary countermeasures.


It seems strange to me that it might be a bug in the client side, since the huge difference between the number of sessions and connections. Also because the browser typically limit by itself the number of connections to the same URL.

Please, if the server log of the Saturday episode is available send us it at support@lightstreamer.com. We will check it in search of clues.

[kpturner]

Update: The number of connections are roughly equivalent to the number of sessions. If I take the server offline for a short period and restart it, the number of connections looks roughly double the number of sessions.....but appear to fall slightly as time goes on.

No scientific proof - but a speculative observation: The longer I leave the server offline the more connections I get for the same number of sessions. Also the more time I take the server offline, the more connections I get:

On startup: 32 sessions and 32 connections
Stop and restart: 32 sessions and approx 50 connections (falling to about 40)
Stop and restart: 32 sessions and approx 90 connections (falling to about 60)
and so on

So if I have 1000 sessions, and the server goes offline for a long period of time and then gets restarted, I think I am going to see some big numbers in the connections statistics compared to the sessions.

I think this only happens with clients that had a good connection, then lost it. They go into an endless connection/fail/retry cycle - and when the server comes on they seem to have more connections than they need.

This may be completely normal and expected of course.