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Re: MySql Proxy 0.7.2 - Network timeout configuration

 

Hi!

On Jul 18, 2009, at 10:31 AM, Urban Loesch wrote:

It takes 3 minutes for the proxy to know that one backend is down or not reachable because of some network interruptions.
I made some tests and I "DROP" all connections from the proxy to the  
first backend with the firewall. So I can simulate a possible  
network interruption to backend 1.
With "netstat" I followed the proxy connection and I see for 3  
minutes a "SYN_SENT" to backend 1, before the proxy is changing the  
connection to   backend 2.
For me it's very important that this timeout is as low as possible,  
perhaps 15 Seconds will be enough.

I'm not sure this is possible because of the way TCP/IP works. Generally systems don't allow tuning the various timeouts employed in TCP. Someone with more intimate knowledge of TCP/IP stacks might want to chime in here, to correct me if possible.
Otherwise, I'm afraid we would need some kind of alarm thread or look  
at using other timeout mechanisms for the non-blocking I/O we do to  
implement this.
If nothing comes out of this discussion, please file a feature request  
at bugs.mysql.com (against Proxy/Core).
cheers,
-k
--
Kay Roepke
Software Engineer, MySQL Enterprise Tools

Sun Microsystems GmbH    Sonnenallee 1, DE-85551 Kirchheim-Heimstetten
Geschaeftsfuehrer:    Thomas Schroeder,  Wolfang Engels,  Wolf Frenkel
Vorsitz d. Aufs.rat.: Martin Haering                    HRB MUC 161028




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