Overview of Integrating XA-Compliant Data Sources in Transactions

The 3Dynamic Server transaction manager, which is an integral part of 3the database server, not a separate module, can invoke support routines 3for each XA-compliant, external data source that participates in 3a distributed transaction at a particular transactional event, such 3as prepare, commit, or rollback. This interaction conforms to X/Open 3XA interface standards.

Transaction support 3in Dynamic Server for XA-compliant, external data sources, which 3are also called resource managers, enables 3you to: 3

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• Create XA-compliant, external data source types and instances 3of XA-compliant, external data sources.
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• Create XA purpose functions, such as xa_prepare, xa_commit, 3and xa_rollback, for each XA data source type to keep external data 3in sync with Dynamic Server transactional semantics.
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• Register XA-compliant, external data sources with a Dynamic 3Server transaction.
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• Unregister XA-compliant, external data sources.
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• Use multiple XA-compliant, external data sources within the 3same global transaction.

The transaction coordination with an XA-compliant, external data 3source is supported only in Dynamic Server logged databases and 3ANSI-compliant databases. These databases support transactions. 3Transaction coordination with an XA-compliant, external data source 3is not supported in non-logged databases.

This chapter contains information on the following processes: 3

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1. Creating user-defined XA-support routines
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2. Creating and dropping XA-compliant, external data source types.
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3. Creating and dropping XA-compliant, external data sources.
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4. Registering and unregistering XA-compliant, external data sources 3as needed.

The IBM Informix MQ DataBlade Module, which provides a set of 3user-defined routines (UDRs) to enable Dynamic Server applications 3to exchange messages between Dynamic Server and IBM WebSphere MQ, 3uses the XA data-source functionality described in this chapter. 3For information on the MQ DataBlade Module, see the IBM Informix: Built-In DataBlade Modules User's Guide.

For general information on XA specifications, refer to the "Distributed 3Transaction Processing: The XA Specification." This is the X/Open 3standard specification that is available on the Internet.