The subtransaction concept is an extension of the multi-DB transaction concept (see “Transaction in multi-DB operation” in the “Application Programming” manual).
A processing chain is a sequence of DML instructions to a single database within a transaction.
All processing chains in a distributed transaction that address the databases of one configuration constitute a single subtransaction.
Example
Consider the following configurations and databases:
CONF-A | CONF-B |
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|
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In this case, a transaction may contain the following subtransactions and processing chains:
Figure 14: Transaction, subtransactions and processing chains for distributed databases with UDS-D
Figure 14 shows a distributed transaction. A transaction is considered to be distributed if it accesses at least one database in a remote configuration.