5.3.1 Configuring the Resource Manager

When you run on Sybase, the value of the xaParameter argument must be the same as that used for the lrm_name parameter, which indicates the logical resource manager (LRM) name that the TPM uses to open the database. The open string for the Sybase database takes the following form:

-Nlrm_name -Uusername -Ppassword [-Llogfile_name] [-Ttraceflags] [-Vversion]

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Consult your Sybase and TPM documentation for complete and accurate connection information.

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The required parameters include:

For more information on the open string parameters, both required and optional, please refer to the XA Interface Integration Guide for CICS, Encina and Tuxedo.

5.3.2 Switch Table

The XA interface describes a structure called a switch table, which lists the names of the xa_ routines implemented in the resource manager. This structure is called xa_switch_t, and is defined in the xa.h header file. The switch table helps build servers that are truly independent of the database vendor being used.

In order to be integrated in the X/Open environment, each resource manager must define the name of its XA switch table. Sybase provides two XA switches:

In spite of the nominal implication that the TUX and TXS switch structures are TPM-specific, the use of these switches is not dependent on the use of Tuxedo or TXS TPMs. Rather, as described above, their use is dependent on whether the application is single-threaded or multithreaded.

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If you are using a single threaded build for the DB XA Module, you must use sybase_TUX_xa_switch as the xa switch table and for multithreaded builds you must use sybase_TXS_xa_switch. The DB XA Module may not function properly if you use the wrong switches.

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You can use the following DB XA method to access the switch table in a database-independent manner:

static void* RWDBManager::xaSwitch(const RWCString& accessLib)

If you have built the DB XA Module using a single-threaded build type, xaSwitch() returns sybase_TUX_xa_switch. If you are using a multithreaded build, this method returns sybase_TXS_xa_switch.

For static libraries, you must supply "SYBASE_CT" to the xaSwitch() method.

(struct xa_switch_t*)RWDBManager::xaSwitch("SYBASE_CT");

For shared libraries, you must supply the name of the access library, using the same name as the non-XA library. For example:

(struct xa_switch_t *)RWDBManager::xaSwitch("libctl420d.so");

Note that the method RWDBManager::xaSwitch(const RWCString&) returns a void*. This return value must be cast to a struct xa_switch_t pointer.

5.3.3 Databases and Connections

The DB XA Module does not open connections to a database server. Instead, it makes use of connections previously opened by the TPM. When the TPM opens a connection to the Sybase SQL Server database, a CS_CONNECTION structure gets allocated. Therefore, the DB XA Module does not use Sybase Open Client Client-Library calls like the following, because these calls explicitly establish connections to database servers:

ct_close ct_con_alloc ct_con_drop ct_con_props(with certain options) ct_config (for details, see the XA Interface Integration Guide for CICS, Encina and Tuxedo) ct_connect ct_exit ct_getloginfo ct_init ct_options (for details, see the XA Interface Integration Guide for CICS, Encina and Tuxedo) ct_remote_pwd ct_setloginfo

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Consult your Sybase and TPM documentation for complete and up-to-date information.

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The connection handle is obtained using the logical resource manager (LRM) name provided during the configuration of the resource manager. The DB XA Module uses a global CS_CONTEXT for all database calls. It fetches the CS_CONNECTION object that was allocated by the TPM using the lrm_name and the thread information, in case the build is multithreaded. For more information about the LRM, see the XA Interface Integration Guide for CICS, Encina and Tuxedo.

5.3.3.1 RWDBDatabase Objects

5.3.3.2 RWDBConnection Objects

The same rules that apply to default connections in a non-XA environment apply in the XA environment. (See the "Databases and Connections" section of the DB Interface Module User's Guide.)

The DB XA Module does not pose any restrictions on the number of connections opened on a single lrm_name. The restriction is placed by the CS_MAX_CONNECT property in the [all] section of the XA configuration file.

Because the retrieval of CS_CONNECTION objects is dependent on the current thread information, connection pooling is turned off when using the DB XA Module with the Sybase Access Module.

Using method RWDBDatabase:: defaultConnections(size_t size) to set default connections in a connection pool will result in a notSupported error.

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Because the TPM actually opens and closes connections, we recommend that you always use explicit connections.

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5.3.4 The Contents of RWDBSystemHandle

5.3.5 The Contents of RWDBEnvironmentHandle

The XA-component of the Sybase Access Module returns an environment handle of type RWDBSybCTXAEnvironmentHandle. This handle derives from RWDBSybCTLibEnvironmnentHandle and redefines the behavior of the following methods: