Tricky Biztalk Orchestration Interview Preparation Guide

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The Orchestration can not promote the properties to message context by default like pipelines can do by using the msg.Context.Promote() method. Inside Orchestration one has to create a correlation set and intialize that correlation set while publishing the message. Then the BizTalk Engine will promote the property to the message context.

Any exception which is not caught within the exception handlers of the orchestration causes the orchestration instance to be moved to the Suspended state. By applying the appropriate error handling in an orchestration it can be prevented entering the Suspended state.

One of the best practices when implementing orchestrations is to use orchestration patterns when possible. These patterns are basically design pattern, which is a general reusable solution to a commonly occurring problem within a given context of BizTalk orchestration. This article will provide some useful resource links to aid you in using patterns when implementing an orchestration.

Correlation is the process of matching an incoming message with the appropriate instance of an Orchestration.

A correlation type is a list of properties that eventually populates with values for use in routing messages.

The term binding refers to the configuration of orchestration ports in order to control the creation of subscriptions and/or promoted properties. Binding is used to control how messages will be routed to or from orchestration ports by the subscription mechanism.

Calling an orchestration will use the same thread to run another orchestration while using Start Orchestration will create a new thread to run the started orchestration.
A Call Orchestration returns the control back to the caller. A Start Orchestration shape starts the orchestration in a non-deterministic way.
As a conclusion, Calling an Orchestration will be synchronous operation where the caller waits for a response, while Start Orchestration is asynchronous operation.

Pro's:
☛ Loose coupling
☛ Not bounded to any physical port (explicitly)

Con's:
☛ Can lead to subscribing to messages published by another publisher

Promoted properties can be used as criteria in message routing while written properties cannot. Property field is a Promoted Property in the context. Distinguished field is a Written property in the context.

The engine will save the state of an orchestration in the following circumstances:
☛ Send Shape (after a message is sent)
☛ Start Orchestration Shape
☛ Suspend Shape
☛ End of a Transactional Scope (atomic or long-running)
☛ An Orchestration Debugger breakpoint is hit
☛ Orchestration Engine determines that the instance needs to be dehydrated
☛ When the Orchestration Engine is shut down; through the controlled shutdown of the host or abnormal circumstances. The engine tries to persist but if that fails, the Orchestration instance will resume from the last successful persistence point.

To route binary data you can use pass-through pipelines on the receive location and send port. BizTalk will route (copy) the data from the source (receive location) to the destination (send port). If you want to route the binary data based on some information in the binary data then you write a custom Disassembler to promote the properties you need from the incoming message to route the binary data.

Unlike traditional programming, BizTalk Server supports two distinct types of transactions: atomic and long-running.

When a variable is shared across the branches of parallel shape.

It is the only exception to the requirement of types for variables having to be serializable and treated as special case.

Expression shape allows for writing XLANG/S statements that provide C# -like coding capabilities.

No, it can only have a Compensation Block.

It can be done using the LoadXml method. Say xmlDoc is a variable then following is done to load employee message.

xmlDoc.LoadXml("<Employee><first_name>Jhon</first_name><last_name>Smith</last_name></Employee>");

The correlation set can have a maximum of three properties used for correlation on the receive shapes.

You construct a message any time that you introduce a message into your orchestration, either by receiving it or by assigning values to a message variable. There are several ways to create a new instance of a message in an orchestration

A scope configured as Atomic or Long running can have compensation blocks added, but scopes that are configured with no Transaction type cannot.

It is used in Specify Later port binding option. In this model the orchestration ports are bound to messaging ports using BTS.SPID,BTS.ReceivePortID or other related properties.

Scopes are used for following reasons:
☛ To configure transaction (long running and atomic)
☛ To handle exceptions
☛ To trigger compensating logic

BizTalk Server architecture is asynchronous for scalability reasons. However, the architecture of the BizTalk Messaging Engine enables exposing a synchronous message exchange pattern on top of these asynchronous exchanges. To do this, the engine handles the complex task of correlating the request and response messages across a scaled-out architecture by linking together a number of asynchronous message exchanges to expose a synchronous interface.

No, It is not possible to use the If Then Else Logic inside the message Assignment. It has to be used in the expression shape.

No. General exception in BizTalk is similar to writing a Try-Catch block but without the exception object thus not possible to get the exception object.