Compaq AA-Q88CE-TE manual DATA=data, DATA=0

CALL RTR_PREPARE_TX

The CALL RTR_PREPARE_TX can only be used in the context of nested transactions (rtr_start_tx was called with the parameter join_txid not equal to NOJOIN_TXID). If this call returns RTR_STS_OK, then the first (prepare) phase of the RTR 2PC protocol has been initiated.

The message type associated with this command is rtr_mt_prepared. Similar to the message types rtr_mt_accepted and rtr_mt_rejected, the rtr_mt_prepared message type returns data of type rtr_status_data_t in the user buffer. In this case, the status field of rtr_status_data_t is always RTR_STS_OK, and the reason field contains the same reason mask that would be returned in the rtr_ mt_accepted message type for the same TX were the TX to be accepted.

Only when the rtr_mt_prepared message is delivered, can the operator be sure that all participants of the nested TX are ready to commit. Alternatively, calling rtr_prepare_tx can result in the message rtr_mt_rejected being delivered if one of the participating servers votes to reject the nested TX.

The rtr_mt_prepared message is only delivered to the console if the rtr_prepare_ tx is called.

A call to rtr_prepare_tx must be followed at some point by a call to rtr_accept_tx (or rtr_reject_tx), which in this context implements the commit phase of the 2PC. (Generally, rtr_prepare_tx and rtr_accept_tx will be called by the foreign TM directly, not by the operator).

Qualifiers

/CHANNEL_NAME=channel_name

/CHANNEL_NAME=RTR$DEFAULT_CHANNEL

Specifies the channel for which the operation is to be performed.

The command server uses a combination of the channel_name and the window from which the call was issued to uniquely identify which channel to use.

channel_name is not case sensitive.

The default channel name is RTR$DEFAULT_CHANNEL.

/DATA[=data]

/DATA=0

The data parameter can be used to pass an ASCII string to RTR that will be saved in the local journal. This string is not sent to the routers or backends, and is used only during recovery, when it is passed back to the client application. RTR does not interpret or modify this data in any way. The maximum size of the data parameter is defined as RTR_MAX_BLOB_LEN and is set to 2048 bytes.

/NODE[=node-list] /NODE=default-node-list (D)

Specifies that the command is executed on all nodes specified in node-list. If node-listis omitted then the command is executed only on the node where the command was issued.

/OUTPUT[=file-spec] /OUTPUT=stdout (D)

Specifies that the resulting information is written to the file file-spec. If /OUTPUT or file-specis omitted then the standard or default output is used.

RTR Command Line Interface 6–23