Mohammed Atef’s Technical blog

BizTalk Host Throttling


Today i am going to talk about Host Throttling, here i am trying to define Host Throttling and it is types . Really all this information are found at Microsoft BizTalk MSDN, but i am trying to reorganize this information to be quick and useful information.

Host Throttling

Most of the processing that takes place on a BizTalk server occurs within host instance, which is a process running as a Windows service.
Manage the use of resources by a host instance process, BizTalk Server utilizes an adjustable throttling mechanism that governs the flow and processing of messages through a host instance
Throttling Benefits
  • Moderates the workload of the host instance to ensure that the workload does not exceed the capacity of the host instance or any downstream host instances.
  • Detects when available resources are being underutilized. If available resources are underutilized then the throttling mechanism allows additional messages to be processed by a host instance
Throttling Configuration
Throttling configuration parameters are set on a per host basis in the BizTalk Server Administration console,
Throttling Configuration Scope
Throttling configuration parameters that are set for the host apply to any or all receive handlers, send handlers, or orchestrations that are housed in the corresponding host instances.

Now lets view two types of Host Throttling

Inbound host throttling Outbound host throttling
Known as
message publishing throttling in BizTalk Server message processing throttling in BizTalk Server
applied to
receive adapters or orchestrations that publish messages to the MessageBox database orchestrations or send adapters that receive and deliver or process messages that have been published to the MessageBox


When condition triggered

  • The amount of memory, the number of threads, or the number of database connections used by the host instance.
  • Downstream hosts are unable to process the messages that are published
  • The Message publishing incoming rate for the host instance exceeds the Message publishing outgoing rate
  • The amount of memory, the number of threads, or the number of database connections used by the host instance.
  • The Message delivery incoming rate for the host instance exceeds the Message delivery outgoing rate
  • The number of messages being processed concurrently by the host instance exceeds the In-process messages per CPU
Severity change and actions
  • delay may be implemented when an End Point Manager (EPM) thread receives a batch of messages from the transport adapter
  • EPM submits a batch of messages to be published into the MessageBox database
  • The number of threads that are available to (EPM) is restricted
  • A progressive delay in the processing logic of the host instance is implemented before delivering the messages to the outbound transport adapter or the orchestration engine for processing the messages.
  • The number of messages that can be held by the in-memory queue is limited.
  • The size of the Message Agent thread pool is limited. By limiting the Message Agent thread pool size, the host throttling mechanism effectively reduces the amount of messages that are delivered to XLANG and adapters.
Default configuration
EPM is configured to use 20 threads per CPU the in-memory queue is set to hold 100 messages per CPU
image image

I Hope that helped


November 3, 2009 - Posted by | Biztalk | ,

No comments yet.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: