This documentation is for WSO2 Enterprise Service Bus version 5.0.0. For the latest ESB, view the latest WSO2 Enterprise Integrator documentation.

All docs This doc

Versions Compared


  • This line was added.
  • This line was removed.
  • Formatting was changed.


Parameter NameDescriptionDefault Value
worker_pool_size_coreInitial number of threads in the worker pool. If the number of live threads is less than the value defined here, a new thread is created to process the response.400

Maximum number of threads in the worker pool.

If the queue (worker_pool_queue_length) is full and the number of live threads is less that the value defined here, a new thread will be created to process the response.


Maximum period of inactivity between two consecutive data packets. Given in milliseconds.


The keep-alive time in seconds for idle threads in the worker pool. Once this time has elapsed for an idle thread, it will be destroyed.

The purpose of this parameter is to optimize the usage of resources by avoiding wastage that results from having idle threads.


The length of the queue that is used to hold runnable tasks to be executed by the worker pool.

If the number of live threads is equal to the core pool size (worker_pool_size_core) and all threads are busy, new tasks will be pushed into the queue so that they can be processed when a thread becomes available.


If you need new threads to be created beyond the core pool size ( worker_pool_size_core ), ensure you change the default value of this parameter so that it becomes a bounded queue

If the queue is full, all threads are busy and the number of live threads is equal to the max pool size ( worker_pool_size_max ), new tasks will be rejected by the worker.

io_threads_per_reactorDefines the number of IO dispatcher threads used per reactor. The value for this property should not exceed the number of cores in the server.2
io_buffer_sizeSize in bytes of the buffer through which data passes.16384 the maximum number of connections allowed per host port.32767
http.socket.reuseaddrIf this parameter is set to true, it is possible to open another socket on the same port as that of the socket which is currently used by the ESB server to listen to connections. This is useful when recovering from a crash. On such occasions, if the socket is not properly closed, a new socket can be opened in order to continue with the listening.true

This is used to configure the SessionInputBuffer size of http core. The SessionInputBuffer is used to fill data that is read from the OS socket. This parameter does not affect the OS socket buffer size.