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Ensemble HL7 Version 2 Development Guide
Settings for HL7 Sequence Managers
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Provides reference information for settings of an HL7 sequence manager.
HL7 sequence managers have the following settings:
Bypass Check On Internal Resent
If this setting is true, the sequence manager bypasses checks on internal resent messages.
Duplicated Message Notice Type
Duplicated Message Target
The configured
Name of an item within the production, usually a business operation. If specified, this is where the sequence manager sends any duplicate messages that it receives.
Enable Duplicated Message Check
If True, the sequence manager checks to see if any incoming messages are duplicates of a previously received message. It does this by checking the following three fields in the MSH segment of each message:
A number that indicates a significant gap in the sequence of messages; the default is 100.
A
late message is a message that arrives with a sequence number larger than the previously received message in the sequence, but not exactly sequential. For example, when message 102 arrives after message 101, 102 is not late; it is the next message in sequence. However, when message 110 arrives after message 101, 110 is a late message.
When there is a late message, and the sequence numbering gap between the preceding and subsequent messages is less than the configured
Large Gap Size, this is a
small gap. A gap larger than this is a
large gap.
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For any small gap, the sequence manager waits for
Message Wait Timeout seconds to see if messages arrive to fill the gap. If the messages arrives within the waiting period, the sequence manager aligns them in their proper sequence. If they do not arrive and the
Message Wait Timeout expires, the sequence manager stops waiting and sends whatever it has for messages in the current sequence.
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When there is a large gap, the sequence manager does not wait for any period of time. It immediately sends an alert, then sends whatever it has for messages in the current sequence.
Message Resendable Time Window
Time window during which the sequence manager considers a duplicate message to be a duplicate. The reason for the
Message Resendable Time Window is that sometimes a duplicate message is not a mistake. Sometimes it is the result of deliberately resending a message sequence.
Suppose a message arrives and the sequence manager detects that it is a duplicate of a previously received message. In this case:
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If it has been more than
Message Resendable Time Window seconds since the sequence manager first saw this message, it interprets the new arrival as a deliberately resent copy. The sequence manager begins tracking the messages in this resent sequence independently from its tracking of the main sequence of messages.
Suppose the sequence manager is processing a sequence that includes numbers such as 1001, 1002, 1003, and 1004, but at the same time it begins receiving messages with the sequence numbers 1, 2, and 3. If the older messages with smaller sequence numbers were first received more than
Message Resendable Time Window seconds ago, the sequence manager interprets them as messages in a resent sequence, rather than as messages out of sequence. It begins tracking the main sequence and the resent sequence simultaneously. While doing so, it keeps the two sequences separate, appropriately ignoring gaps between unrelated sequence numbers such as 2 and 1001.
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For definitions of large gaps, small gaps, and late messages, see the
Large Gap Size setting.
For any small gap, the sequence manager waits for
Message Wait Timeout seconds to see if messages will arrive to fill the gap between the preceding message and the late message. If they do not arrive and the
Message Wait Timeout expires, the sequence manager stops waiting and sends whatever it has for messages in the current sequence.
Out Of Sequence Message Notice Type
Out Of Sequence Message Target
The configured
Name of an item within the production, usually a business operation. If specified, this is where the sequence manager sends any out-of-sequence message notices.
Output Facility Application
Output Sequence Number Index Field
Controls the fields on which the output sequence number is incremented. Specify one of the following values:
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Sender — The index fields are MSH:3 SendingApplication and MSH:4 SendingFacility.
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Receiver — The index fields are MSH:5 ReceivingApplication and MSH:6 ReceivingFacility.
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Output Target Config Names
A comma-separated list of configured items within the production. If specified, this list identifies the destinations to which the sequence manager will send any message that passes its tests.
Passthrough Message Types
A comma-separated list of message types that are exempt from duplicate checks, sequence checks, or output transformations. The sequence manager always passes these messages through unchanged. The default list is:
Perform Output Transformation On
Specifies fields to transform before sending out a message. The output transformation provides new facility, application, and sequence number fields as described in the following list, then sends the message to its configured targets. Possible values for
Perform Output Transformation On are:
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MSH:5 ReceivingApplication
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None — The sequence manager does not perform any transformation before sending the message.
Perform Sequence Number Check On
Specifies the fields to check to see if any of the incoming messages are out of sequence. If so, the sequence manager resequences the messages and sends them to its configured targets.
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Sender — This is the default. The sequence manager checks:
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MSH:5 ReceivingApplication
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MSH:5 ReceivingApplication
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None — The sequence manager does not check for messages out of sequence.