Post Training presentation on BizTalk orchestrations (tips and tricks), part 1 of 2.

1. BizTalk Orchestrations
2nd Presentation
Wajih Arshad

2. Topics
 Scope
 Use of scope for transactions
 Synchronization
 Exception handling
 Compensation
 Orchestration shapes in BizTalk 2004

3. Scope Shape
 Defines scope in a flow
 Used to implement transactions
 Used to implement synchronization
 Scope is not just a visual element, unlike Group shape
 Used for exception handling and compensation

4. Nesting scopes
Scope shapes can nest other scope shapes, subject to
following conditions:
 Atomic transactional scopes cannot nest other
transactional scopes
 Transactional scopes cannot be nested in non-
Transactional scopes
 Transactional scopes cannot be nested in synchronized
scopes and their exception handlers
 Synchronized scopes cannot be nested in other
synchronized scopes and their exception handlers
 CALLed orchestrations (nested orchestrations) are
treated as nested transactions
 STARTed orchestrations (nested orchestrations) do not
have nesting scopes applying on them
Source: MSDN

5. Scope Shape: Synchronization
 Scope shape is used to declare a synchronized boundary
(Synchronized block)
 Synchronization avoids chances of data sharing and
corruption
 All orchestration actions within a synchronized scope are
synchronized
 Scopes do not hide variable names, unlike programming
languages
 Synchronization can help avoid deadlocks, though
improper design can still lead to deadlocks

6. Scope Shape: Use for transactions
How to make a transactional block?
1. Set the whole orchestration as “Long Running” transaction
2. Add a scope shape to define boundary of transaction
3. Set the Transaction property of the scope to “Atomic” or
“Long Running”

7. Scope Shape: Properties for transactions
 Batch
 Timeout
 Retry
 Isolation (Serializable, Read Committed, Repeated Read)
 Synchronization (does not matter for atomic transactions)

8. Exception Handling
 Exception handler can be associated with a scope
(other than Atomic Transaction scope)
 Exception handler can be configured to catch a .NET
exception object or derived exception object
 “Throw Exception” shape can be used to throw or re-throw
an exception

9. Exception Handling (Cont.)
 Timeout events result in exceptions and can be handled
accordingly
 Exception handler can contain other scopes
 To associate an exception handling block with a scope,
right click the scope shape and select “New Exception
Handler”

10. Compensation
 Used to remove the effects of a failed transaction
 Can be used to undo a committed transaction
 Both Atomic and Long Running transactions can have
compensation block, though exception handling block is
not allowed in Atomic transactions
 Compensation blocks can contain transaction blocks
 One scope can have only one compensation

11. Compensation: Order of execution
 A default compensation is provided and invoked if
one is not added
 Compensation blocks are executed in reverse order:
from compensation of outermost transaction to that of innermost.
 Compensation blocks are executed in reverse order
for loops: starting from last iteration back to the first iteration
 “Compensate” shape can be used in compensation
block to over-ride this default flow