Convoy Processing in BizTalk Orchestration

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Convoy Processing in BizTalk Orchestration
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What is a Convoy?
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Convoy Definition

• A message may contain a field, or set of
  fields, whose values identify it as a member of a
  group of related messages, for example a unique
  PO number, or a SSN. A convoy scenario is one in
  which
• The values are not known before the arrival of
  the first message. That is, the first messages
  "defines" the group.
• Succeeding messages in the group may arrive
  before any further processing or synchronization
  takes place.
• All messages in the group must be processed by
  the same handler.

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Scenarios Supported by BizTalk Parallel Convoy

• The messages may be of different types. There is
  no defined order in which the messages are
  expected to arrive. The handler accepts them in
  any order and may process them in parallel.
• Clearinghouse example.

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Parallel Convoy Restrictions

1. If one of the tasks of a parallel has an
   activatable receive as the first shape, all of
   the tasks of that parallel must have an
   activatable receive as the first shape and all of
   these receives must initialize at least one
   correlation.
2. If a particular correlation is initialized on
   more than one task of a parallel by a receive,
   each of the concerned receives must initialize
   exactly the same correlations.
3. If a particular correlation is initialized on
   more than one task of a parallel by a
   non-activation receive, each one of such receives
   must also follow (i.e., non-initialized
   correlation reference) the same correlation set.

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Scenarios Supported by BizTalk Uniform
Sequential Convoy

• The messages are all of the same type from the
  same party. There is no defined order to the
  messages. The handler processes them sequentially
  as delivered.
• Streaming example.

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Scenarios Supported by BizTalk Non-Uniform
Sequential Convoy

• The messages, all from the same party, may be of
  different types however the order in which the
  messages are expected to arrive is predefined.
  The handler processes them in the expected order.
  
• Heath care example.

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Convoy Set

• A Convoy-set for a particular receive shape, is
  the set of correlation sets that are initialized
  by another receive shape and followed by this
  particular receive shape.
• Any correlation set that is being followed by a
  send shape (chronologically) prior to the
  particular receive shape is not considered as a
  part of the Convoy-Set.
• This caveat in in-place more because of
  limitation of the current implementation rather
  than any other semantic concerns. The problem
  being that given a single service it is
  impossible to detect whether convoy processing
  would be required in such cases it can really
  be totally determined after looking at the
  partner service and examining the protocol. This
  is a useful warning to provide so that the user
  can examine the program the protocol and take
  corrective action. (Warning 4014)

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Sequential Convoy Semantic Checks

1. All the correlation sets that constitute a Convoy
   Set for a particular receive shape must be
   initialized by one and only one preceding receive
   shape.
2. The port for a particular receive shape, that
   requires convoy processing, must match the port
   for the receive shape initializing the convoy
   set.
3. If a sequential convoy is initialized by an
   activate receive, then the follower receives
   cannot be inside a service called from the
   activated service.

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Additional Semantic checks for Uniform Sequential
Convoys

• Message types being received for a particular
  receive shape, requiring convoy processing, must
  match the message type for the receive shape
  initializing the convoy set unless the receive
  shape is operating on an Ordered Delivery port.
• All receives participating in a particular
  sequential Convoy must follow all the correlation
  sets that are initialized (or followed) by the
  initializing receive unless operating on an
  Ordered Delivery port.
• If a sequential convoy is initialized by an
  activate receive, then the activate receive
  cannot have a filter expression unless operating
  on an Ordered Delivery port.

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Associated Orchestration Build Error Messages

• ERROR 2257 if a parallel has an activatable
  receive then all its' tasks must be activatable
• ERROR 2022 a sequential convoy which is
  initialized by an activate receive may not call
  or compensate a service with a receive
  participating in the convoy.
• ERROR 2258 in a sequential convoy receive all
  correlations must be initialized in a single
  receive  
• ERROR 2259 in a sequential convoy receive the
  ports must be identical  
• ERROR 2260 in a sequential convoy receive the
  messagetypes must be identical unless the port is
  marked for OrderedDelivery
• ERROR 2261 in a parallel convoy receive the
  correlations must be identical  
• ERROR 2262 a parallel activate receive convoy
  must initialize correlations 
• ERROR 2263 in a sequential convoy receive there
  cannot be an activation filter unless the port is
  marked for OrderedDelivery
• ERROR 2264 in a sequential convoy receive the
  correlations must be identical unless the port is
  marked for OrderedDelivery
• WARN 4014 convoy processing will not occur --
  check your protocol if you were expecting it

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Questions?