Heterogeneous Commit Protocol

Used in the context of Informix database servers, the term heterogeneous environment refers to a group of database servers in which at least one of the database servers is not an Informix database server. Heterogeneous commit ensures the all-or-nothing basis of distributed transactions in a heterogeneous environment.

Unlike the two-phase commit protocol, the heterogeneous commit protocol supports the participation of a non-Informix participant. The non-Informix participant, called a gateway participant, must communicate with the coordinator through an IBM Informix gateway.

The database server uses heterogeneous commit protocol when the following criteria are met:

• Heterogeneous commit is enabled. (That is, the HETERO_COMMIT configuration parameter is set to 1.)
• The coordinator of the commit is a Version 7.2 or later IBM Informix Dynamic Server.
• The non-Informix participant communicates with the Informix database server through an Informix gateway.
• At most, one non-Informix participant performs an update within a single transaction.

Figure 88 illustrates this scenario.

Figure 88. Configuration That Requires Heterogeneous Commit for Distributed Transactions