Service Behavior In WCF

• NetNamedPipeBinding
• NetTCPBinding
• WSHttpBinding
• WSDualHttpBinding
• WSFederationHttpBinding

We will now discuss two important attributes we need to define in the transaction, they are TransactionScopeRequired and the TransactionAutoComplete properties in operation behavior.

TransactionScopeRequired: True, it means if the client propagates the transaction to the operation, it will be the one to use in the service side. If the client did not propagate any transaction then it creates its own transaction and uses it. Please look at the following source code to understand how we should declare it in the client and server side.

TransactionAutoComplete: True, this setting instructs the WCF to auto-commit the transaction at the end of the code block. It can be configured only at the service level.

So far we have learned about the usage of transaction attributes, now let's see various options in configuring transaction modes.

Did you understood the Title "Use Client's T or Use your OWN T"? I hope you couldn't .

Yes, let me explain it here. The following procedure will determine whether the client's transaction is propagated or otherwise create your own transaction and use it.

• Set the transaction Flow attribute to True on both the client and service
• Set the Transaction Flow allowed on the operation contract
• Set the TransactionScopeRequired and TransactionAutoComplete attributes of the operation contract to True

If you are still not clear then please refer to the attached source code.

Yes the following procedure determines whether the Hello Service, doesn't use or create a transaction, use only the client's transaction.

• Set the transaction Flow attribute to True on both the client and service
• Set the Transaction Flow Mandatory on the operation contract
• Set the TransactionScopeRequired and TransactionAutoComplete attributes of operation contract to True

Use only Service's T

The following procedure determines whether that Hello Service, doesn't use another transaction, use your own transaction (Service)

• Set the transaction Flow attribute to True on both the client and service
• Set the Transaction Flow Not Allowed on the operation contract
• Set the TransactionScopeRequired and TransactionAutoComplete attributes of operation contract to True

Don't use T

The following procedure determines whether that Hello Service, doesn't use any transaction.

• Set the transaction Flow attribute to True on both the client and service
• Set the Transaction Flow Not Allowed on the operation contract
• Set the TransactionScopeRequired and TransactionAutoComplete attributes of operation contract to True

So far we have seen what transactions are. What are all the types of protocols it uses? What are all the procedures involved in configuring transactions in WCF? How should we configure different transaction modes? Now we shall see what exactly the process involved during the transaction. The transactional manager manages the transactions across the process or boundaries. It uses either the OleTx Protocol or the WSAT protocol to manage, namely the Distributed Transaction Manager (DTC). DTC actually uses the management protocol 2 Phase Commit Protocol to manage the distributed transaction across machines. There are two phases that DTM uses to manage the distributed transaction.

• Prepare
• Commit

In the Prepare phase, DTC asks each resource manager (SQL) to vote on either commit or abort through an RPC call, then each Resource manager (SQL) gives their votes to DTC saying Yes or No.

In the Commit phase, DTC asks all resource managers to commit or abort based on the votes received yes or no.

Coordinator Cohort
QUERY TO COMMIT
-------------------------------->
VOTE YES/NO prepare*/abort*
<-------------------------------
commit*/abort* COMMIT/ROLLBACK
-------------------------------->
ACKNOWLEDGMENT commit*/abort*
<--------------------------------
end

But please don't worry about which transaction manager I need to use, how I need to manage and all, because all these operations are managed by the WCF internally. Please refer to the attached code for further details.

Service Behavior: Throttling exposes properties that you can control how many instances or sessions are created at the application level. For example the number of service instances, the creating should not be more than the specific value.

To define the number of concurrent calls that the service will accept. The default value in .Net 4.0 is 16 * processor count. Prior to .Net 4.0 it was 16.

To define the number of session channels that the service will accept. By default in .Net 4.0 the default value is 100 * processor count, prior to .Net 4.0 the default value was 10.

To define the number of service instances will be created. By default in .Net 4.0 the default value will be 26, whereas in .Net 4.0 the default value will be 116 * processor count.

Please refer to the folder Transaction for the Transaction sample, refer to the folder Throttling for the Throttling samples

CTS: Concurrency, Throttling, Transactions are important topics in service behavior.