Delta
This tab is only available in Iterator mode.
The parameters in this tab have the following significance:
- Enable Delta
- This is the master switch for the Delta engine for this Connector. If not selected, the parameters below are not enabled.
- Unique Attribute Name
- This is the name of an attribute, or a choice of multiple input attributes separated by "+", that holds a unique value in a given data source. Data sources with duplicate keys cannot be subjected to the delta function, except when Allow duplicate Delta keys is enabled. See Delta Detection for more information.
- Delta Store
- The table in the System Store that holds the Delta information from previous runs for this Connector, so as to be able to detect differences on subsequent runs.
- Read Deleted
- If checked, the AssemblyLine will inject deleted entries into the AssemblyLine run when the Iterator has completed iterating, that is, finished input. The operation code will indicate that this entry was deleted in the input source. Note that delete-tagged Entries are not removed from the Delta Store unless you also enable the Remove Deleted flag.
- Remove Deleted
- If checked, the deleted entries from the input source are deleted from the Delta Store, such that they will not be detected again in subsequent runs.
- Return Unchanged
- If checked, any unchanged entries in this run are injected into the AssemblyLine.
- Commit
- Selects when to commit changes to the Delta Store as a result
of iterating through the input. Choices are:
- After every database operation
- On end of AL Cycle
- On Connector close
- No autocommit
The default is After every database operation.
- Row Locking
- Selects the transaction isolation level for the connection to
the Delta Store. This parameter addresses the need for row locking
in a Delta Store table when multiple DB Clients access the same data,
by setting a Transaction Isolation Level. Setting a higher
isolation level reduces the transaction anomalies known as 'dirty
reads', 'non-repeatable reads' and 'phantom reads' by using row and
table locksChoices are:
- READ_UNCOMMITTED
- READ_COMMITTED
- REPEATABLE_READ
- SERIALIZABLE
The default is READ_COMMITTED. For more information, see section Row Locking.
- Attribute List
- This is a list of comma separated attributes whose changes will be detected or ignored during the compute changes process. The changes in listed attributes will be affected by the Change Detection Mode parameter, which specifies whether to ignore or detect them. For more information about this parameter and the next, see section Detect or ignore changes only in specific attributes.
- Change Detection Mode
- Specify whether to detect or ignore changes in Attributes listed
in the Attribute List parameter. Possible values
are:
- IGNORE_ATTRIBUTES
- DETECT_ATTRIBUTES
- DETECT_ALL
- Faster algorithm
- When checked, instructs the AssemblyLine to use a faster algorithm to compute changes, at the expense of more memory use.
- Allow duplicate Delta keys
- When the Delta feature is enabled for Changelog/Change Detection Connector in long running AssemblyLines, it is possible that an Entry can be modified more than once. These modifications will result in receiving the Entry second time and this will cause a Duplicate delta key exception to be thrown. Checking this parameter allows Entries with duplicate key attributes (specified in the Unique Attribute Name parameter) to be processed by Iterator Connectors with enabled Delta.