RE: Exceeding Number of Connections

As far as I know this shouldn't occur. When you specify in your NETTYPE the number of connections it won't allow you to exceed that number. When you executed onstat -u are the session ids unique? It's possible that a session (connection) spawned more than one thread. And what you're seeing are the multiple threads for the same session number. Don -----Original Message----- From: Red Valsen [mailto:red_valsen@yahoo.com] Sent: Wednesday, October 18, 2000 1:48 PM To: informix-list@iiug.org Subject: Exceeding Number of Connections What are the practical effects of exceeding the number of connections that a poll thread is set to handle via onconfig file's NETTYPE parameter? During functional testing, we inadvertently created over 750 connections (as reported by onstat -u) with NETTYPE set to tlitcp,1,128,NET. We observed no ill effects -- performance degradation, slowness spawining additional connections, server dying, etc. So what is actually happening here? Is the poll thread actually doing any "work," or just establishing and disconnecting sockets? We're running IDS 7.31.UC4 on Solaris2.7/Intel (don't ask).

Hi, NETTYPE establishes an actual limit for shared memory connections only. In the shared memory case the nettype settings basically define the number of 'memory slots' that clients can use to pass messages to the database server. For all other connection types it is rather a tuning parameter that helps the engine to estimate how much memory it should set aside for networking purposes. If there is a performance problem it would show up as non-zero values in the 'q-exceed' columns of the 'global network information' section in the 'onstat -g ntt' output. Versions 9.21 and later include a column 'alloc/max' in the 'onstat -g ntt' output that allows to check how many network buffers are currently allocated and the maximum of used buffers. These values would give you an indication on what has to be configured for NETYPE. More information on this topic can be found in the MaxConnect manual ( http://www.informix.com/answers/english/docs/10maxcon/6678.pdf , p 5-8ff). More comments below. Don Ignacio wrote: > As far as I know this shouldn't occur. When you > specify in your NETTYPE the number of connections > it won't allow you to exceed that number. > > When you executed onstat -u are the session ids > unique? It's possible that a session (connection) > spawned more than one thread. And what you're seeing > are the multiple threads for the same session number. > > Don > > -----Original Message----- > From: Red Valsen [mailto:red_valsen@yahoo.com] > Sent: Wednesday, October 18, 2000 1:48 PM > To: informix-list@iiug.org > Subject: Exceeding Number of Connections > > What are the practical effects of exceeding the number of connections > that a poll thread is set to handle via onconfig file's NETTYPE > parameter? During functional testing, we inadvertently created over > 750 connections (as reported by onstat -u) with NETTYPE set to > tlitcp,1,128,NET. We observed no ill effects -- performance > degradation, slowness spawining additional connections, server dying, > etc. So what is actually happening here? Is the poll thread actually > doing any "work," or just establishing and disconnecting sockets? The pollthread is doing more work with more connections (even if there is no traffic for the additional connections). You would probably see an performance degradation as you add additional sessions. Hope this helps, Heiko