In Tomcat server.xml what is maxThreads versus maxConnections
I understand that maxConnections is the number of connections open to the server
And maxThreads is the maximum number of request processing threads
But how the two configuration parameters working together, obviously you will not set maxConnections to 1000 and maxThreads to 10
What is the relationship between the two configuration parameters?
<Connector
port="8443"
protocol="org.apache.coyote.http11.Http11Protocol"
maxThreads="250"
SSLEnabled="true"
scheme="https" secure="true"
clientAuth="false"
sslProtocol="TLS"
connectiontimeout="20000"
/>
Tomcat can work in 2 modes:
Tomcat 7 is BIO by default, although consensus seems to be "don't use Bio because Nio is better in every way". You set this using the protocol parameter in the server.xml file.
HTTP/1.1 or org.apache.coyote.http11.Http11Protocol org.apache.coyote.http11.Http11NioProtocolIf you're using BIO then I believe they should be more or less the same.
If you're using NIO then actually "maxConnections=1000" and "maxThreads=10" might even be reasonable. The defaults are maxConnections=10,000 and maxThreads=200. With NIO, each thread can serve any number of connections, switching back and forth but retaining the connection so you don't need to do all the usual handshaking which is especially time-consuming with HTTPS but even an issue with HTTP. You can adjust the "keepAlive" parameter to keep connections around for longer and this should speed everything up.
From Tomcat documentation, For blocking I/O (BIO), the default value of maxConnections is the value of maxThreads unless Executor (thread pool) is used in which case, the value of 'maxThreads' from Executor will be used instead. For Non-blocking IO, it doesn't seem to be dependent on maxThreads.
Source: Stackoverflow.com