The way to obtain data is to specify the requirement as parameters to rtr_request_info() . RTR then opens a channel on which the requested information can be received by calling rtr_receive_message() on the channel. The channel is automatically closed when the requested data (if any) has been completely delivered (that is, an rtr_mt_closed message is received on the channel.) You may close the channel earlier, if no more information is needed, by calling rtr_close_channel() .

The selection criteria specify an information class, a select item and a value. This is like doing a table lookup, where the class represents the specific table, and the select item and value represent the row and column in the table. For example, the following statement: rtr_request_info/channel=I/infcla=rtr/selitm=""/ selval="*" /getitms=rtr_version_string requests information from the RTR (rtr) information class.

The rtr_request_info() call accesses the RTR tables in memory as follows:

1. The infcla parameter selects the class to be accessed, for example "rtr".
2. The selitm parameter names the row of the RTR table in memory to be accessed. This can be a null string, for example selitms="" to retrieve all data for the class.
3. The selval parameter defines what to search for in the row. For example, in a table containing information about backend transactions, if selitm specifies fac_id indicating that a facility name is the selection criterion, and if selval contains the value "TESTFAC", RTR selects only transactions for the facility TESTFAC.
4. The getitms parameter specifies the items to be returned from the selected row(s). In the example of a table containing information about backend transactions, rtr_request_info can specify transaction ID and transaction start time. The data for these items are returned for all transactions matching the selection criteria.

The results of the selection are returned as none, one, or more messages of type rtr_mt_request_info , one message being returned for each selected row in the table (in a btx example, one message for each backend transaction).

The contents of these messages are defined by the getitms parameter. For example, if three item names specified for getitms are "item_1,item_2,item_3", then the corresponding rtr_mt_request_info message or messages contain three concatenated and null-terminated strings that are the values of those fields, "value1\0value2\0value3\0".

Return Value A value indicating the status of the routine. Possible status values are:

RTR_STS_CLASSREQ	At least one data-class definition required
RTR_STS_INVCHANNEL	Invalid pchannel argument
RTR_STS_INVFLAGS	Invalid flags argument
RTR_STS_INVGETITMS	Invalid getitms argument
RTR_STS_INVINFCLA	Invalid information class
RTR_STS_INVSELITM	Invalid selitm argument
RTR_STS_INVSELVAL	Invalid selval argument
RTR_STS_OK	Normal successful completion

Example

Programming Example:

/* This routine retrieves the facility names of all facilities that have been defined. */ #include <string.h> #include <stdio.h> #include "rtr.h" void GetFacilityName() { char* itemlist[10]; /* Set the elements in this array to point to each item in getitembuf for later output. */ char* cp = 0; char getitembuf[1024]; rtr_status_t status; rtr_channel_t channel; char msg[1024]; /* Receive message buffer. */ unsigned int getitemcnt = 0; char infcla_buf[4] = "fac"; /* Set info class to Facility class.*/ rtr_msgsb_t txsb; getitembuf[0] = '\0'; /* Set up the request's get-item buffer for requesting the facility name. */ itemlist[getitemcnt] = &getitembuf[strlen(getitembuf)]; strcat(getitembuf, "fdb_f_name"); /* Increment counters. */ getitemcnt++; /* Add second item FE -> TR. ** Code commented out ** */ /* (Demonstrates multi-item request. Uncomment code to use.) strcat(getitembuf, ","); //Add comma separator. itemlist[getitemcnt] = &getitembuf[strlen(getitembuf)]; strcat(getitembuf, "fdb_trsrch"); getitemcnt++; */ /* Call rtr_request_info. */ status = rtr_request_info ( /* *pchannel */ &channel, /* flags */ RTR_NO_FLAGS, /* infcla */ infcla_buf, /* selitm */ "", /* selval */ "*", /* getitms */ getitembuf); if (status != RTR_STS_OK) return; /* Do a receive message to get the information that RTR returns * in response to this request. */ do { status = rtr_receive_message( /* See 'rtr_receive_message'. */ &channel, RTR_NO_FLAGS, RTR_ANYCHAN, msg, sizeof(msg), RTR_NO_TIMOUTMS, &txsb); /* Check for bad return status from rtr_receive_message(). */ if (status != RTR_STS_OK) return; /* Caller expects either an rtr_mt_closed or an rtr_mt_request_info message. */ if (txsb.msgtype == rtr_mt_closed) break; /* End of data, exit loop. Channel closed by RTR. */ if (txsb.msgtype != rtr_mt_request_info) { printf("Unexpected msgtype returned. \n"); break; } else { /* Receive the requested information. Scan through item list, output item and value. */ unsigned int i; for (i=0, cp = msg; i < getitemcnt; i++, cp += strlen(cp)+1) { *(itemlist[i+1]-1) = '\0'; /* Overwrite comma. */ printf("%-8s:%40s\t= '%^s'\n", infcla_buf, itemlist[i], cp); } } } while (1 == 1); return;

Command Line Example:

RTR> call rtr_request_info/infcla=rtr/selitm="" /selval="*"/getitms=rtr_version_string/chann=D %RTR-S-OK, normal successful completion RTR> call rtr_receive_message/chann=D/tim %RTR-S-OK, normal successful completion channel name: D msgsb msgtype: rtr_mt_request_info msglen: 18 message offset bytes text 000000 52 54 52 20 56 33 2E 32 28 32 33 30 29 20 46 54 RTR V3.2(230) FT 000010 33 00 3.

See Also

rtr_close_channel()
rtr_receive_message()

Send a transactional message to a server.

Syntax

status = rtr_send_to_server (channel, flags, pmsg, msglen, msgfmt)

Argument	Data Type	Access
status	rtr_status_t	write
channel	rtr_channel_t	read
flags	rtr_sen_flag_t	read
pmsg	rtr_msgbuf_t	read
msglen	rtr_msglen_t	read
msgfmt	rtr_msgfmt_t	read

C Binding

rtr_status_t rtr_send_to_server (

rtr_channel_t channel ,
rtr_sen_flag_t flags ,
rtr_msgbuf_t pmsg ,
rtr_msglen_t msglen ,
rtr_msgfmt_t msgfmt ,
)

Arguments

channel

The channel identifier (returned earlier by rtr_open_channel() ).

flags

Table 3-25 shows the flags that specify options for the call.

Table 3-25 Send to Server Flags

Flag name	Description
RTR_F_SEN_ACCEPT	This is the last message of the transaction, and the tx is accepted. This optimization avoids the need for a separate call to rtr_accept_tx() in those cases where the sender knows this is the last (or only) message in the transaction.
RTR_F_SEN_READONLY	Specifies a read-only server operation. Hence no shadowing or journalling is required. (The message is still written to the journal but is not played to a shadow and is purged after the transaction is completed on the primary. The message is still needed in the journal to allow recovery of in-flight transactions.)
RTR_F_SEN_RETURN_TO_SENDER	The message is to be returned to the sender if undeliverable.
RTR_F_SEN_EXPENDABLE	The whole transaction is not aborted if this send fails.

Specify RTR_NO_FLAGS for this parameter if no flags are required.

pmsg

Pointer to the message to be sent.

msglen

Length in bytes of the message to be sent, up to RTR_MAX_MSGLEN bytes. The value of RTR_MAX_MSGLEN is defined in rtr.h .

msgfmt

Message format description. msgfmt is a null-terminated character string containing the format description of the message. RTR uses this description to convert the contents of the message appropriately when processing the message on different hardware platforms. See Section 2.14, RTR Applications in a Multiplatform Environment, for information on defining a message format description.

This parameter is optional. Specify RTR_NO_MSGFMT if the message content is platform independent, or it is not intended to be used on other hardware platforms.

Description

The rtr_send_to_server() call sends a client's transactional message to a server.

The caller must first open a client channel (using the rtr_open_channel() call), before it can send transactional messages.

If no transaction is currently active on the channel, a new transaction is started.

Example

/* The my_msg structure is defined in the user's * application header file. */ typedef struct { rtr_uns_8_t routing_key; rtr_uns_32_t sequence_number; rtr_uns_8_t my_msg_type; string31 last_name; rtr_uns_32_t order_total; rtr_uns_32_t shipping_amt; string16 cc_number; string7 cc_expire; } my_msg; my_msg send_msg; . . Load purchase data into send_msg. . /* * Tell the server to validate the credit card for the * amount of this order. */ my_msg.my_msg_type = VALIDATE_CC; status = rtr_send_to_server( channel, RTR_NO_FLAGS , &send_msg, sizeof(send_msg), RTR_NO_MSGFMT );

See Also

rtr_receive_message()
rtr_open_channel()

Sets or changes a managed object in the RTR environment.

Syntax

status = rtr_set_info (*pchannel, flags, verb, object, *select_qualifiers, *set_qualifiers)

Argument	Data Type	Access
status	rtr_status_t	write
*pchannel	rtr_channel_t	write
flags	rtr_set_flag_t	read
verb	rtr_verb_t	read
object	rtr_managed_object_t	read
*select_qualifiers	rtr_qualifier_value_t	read
*set_qualifiers	rtr_qualifier_value_t	read

C Binding

rtr_status_t rtr_set_info (

rtr_channel_t *pchannel ,
rtr_set_flag_t flags ,
rtr_verb_t verb ,
rtr_managed_object_t object ,
const rtr_qualifier_value_t *select_qualifiers ,
const rtr_qualifier_value_t *set_qualifiers
)

Arguments

pchannel

Pointer to the channel opened by a successful call to rtr_set_info() .

flags

No flags are currently defined. Specify RTR_NO_FLAGS for this argument.

verb

Always rtr_verb_set .

object

Establishes the type of object to which the call is directed. Values are:

• rtr_partition_object : the target object is a partition
• rtr_transaction_object : the target object is a transaction

select_qualifiers

Pointer to array containing selection qualifiers. Values depend on object type:

For:	See the values in:
Set Partition	Table 3-26
Set Transaction	Table 3-27

For example:

typedef struct rtr_qualifier_value_t { rtr_qualifier_t qv_qualifier ; /* Which qualifier this is */ void *qv_value ; /* What value it has */ } rtr_qualifier_value_t ;

The last value in the array must be rtr_qualifiers_end (see the example). Specify sufficient descriptors to identify the target object.

Table 3-26 Select Qualifiers for the Set Partition Object

Qualifier	Value Type	Description	Example
rtr_facility_name	const char*	Facility name string	"facility_name"
rtr_partition_name	const char*	Partition name string	"partition_name"

Table 3-27 Select Qualifiers for the Set Transaction Object

Qualifier	Value Type	Description	Example
rtr_facility_name	facname	Facility name string	"facility_name"
rtr_partition_name	partname	Partition name string	"partition_name"
rtr_txn_state	rtr_txn_jnl_commit	Current transaction state	See Table 3-28 for valid changes from one state to another.
rtr_txn_tid	tid	Transaction ID	63b01d10,0,0,0,0,2e59,43ea2002

When using the Set Transaction Object, the qualifier rtr_txn_state is required. In addition, when using rtr_txn_state without rtr_facility_name or rtr_partition_name , rtr_txn_tid is required. The qualifiers rtr_facility_name and rtr_partition_name must be used together. You must always provide the current state when making a state change.

Table 3-28 Valid Set Transaction State Changes

From (current state):	To (new state):
	ABORT	COMMIT	DONE	EXCEPTION
COMMIT			YES	YES
EXCEPTION		YES	YES
PRI_DONE (remember)			YES
SENDING	YES
VOTED	YES	YES

set_qualifiers

Pointer to an array containing values of type rtr_qualifier_value_t (see Select Qualifiers above) that describe the desired change to be effected. Table 3-29 and Table 3-30 list qualifiers and value types for the managed object types.

Table 3-29 Qualifiers for Set Partition

Qualifier	Value Type	Value	Desired Action
rtr_partition_state	rtr_partition_state_t	rtr_partition_state_suspend	Suspend transaction presentation.
rtr_partition_state	rtr_partition_state_t	rtr_partition_state_resume	Resume transaction presentation.
rtr_partition_state	rtr_partition_state_t	rtr_partition_state_recover	(Re)start partition recovery.
rtr_partition_state	rtr_partition_state_t	rtr_partition_state_exitwait	Exit partition recovery wait/fail state.
rtr_partition_state	rtr_partition_state_t	rtr_partition_state_shadow	Enable shadowing.
rtr_partition_state	rtr_partition_state_t	rtr_partition_state_noshadow	Disable shadowing.
rtr_partition_cmd_timeout_secs	rtr_uns_32_t	unsigned int	Optional partition suspend timeout period (in seconds).
rtr_partition_rcvy_retry_count	rtr_uns_32_t	unsigned int	Limit number of recovery replays for a transaction.
rtr_partition_failover_policy	rtr_partition_failover_policy_t	rtr_partition_fail_to_standby	Set failover policy to standby.
rtr_partition_failover_policy	rtr_partition_failover_policy_t	rtr_partition_fail_to_shadow	Set failover policy to shadow.
rtr_partition_failover_policy	rtr_partition_failover_policy_t	rtr_partition_pre32_compatible	Set failover policy as pre-V3.2 compatible.

For both managed object types, a message of type rtr_mt_closed is returned. See Table 3-30 for the value that can be set for the transaction type.

Completion status is read from message data, which is of type
rtr_status_data_t . In addition, a number (type integer) indicating the number of transactions processed is returned. This number can be read from the message following the rtr_status_data_t data item. The last value in the array must be rtr_qualifiers_end .

Table 3-30 Qualifiers for Set Transaction

Set Qualifier	Set Qualifier Value	Value	Description
rtr_txn_state	rtr_transaction_state_t	rtr_tx_jnl_commit	Set a transaction's state to COMMIT to commit the transaction.
rtr_txn_state	rtr_transaction_state_t	rtr_tx_jnl_abort	Set a transaction state to ABORT to abort the transaction.
rtr_txn_state	rtr_transaction_state_t	rtr_tx_jnl_exception	Mark this as an exception transaction.
rtr_txn_state	rtr_transaction_state_t	rtr_tx_jnl_done	Remove this transaction from the RTR journal; that is, forget this transaction completely.

Description

The rtr_set_info() call requests a change in a characteristic of the RTR environment. If the call is successful, a channel is opened for asynchronous completion notification. Applications should use the rtr_receive_message() call to retrieve informational messages on the opened channel.

The rtr_set_info() call can manipulate two managed object types:

• Partition type
• Transaction type

See Table 3-29 for values that can be set for the partition object and Table 3-30 for values that can be set for the transaction object. Completion status is read from message data, which is of type rtr_status_data_t .

Example

/* * This might follow a call to commit the transaction to the database. * If the SQL commit returns an error that is beyond the control of * this application: for example, database disk full, network to * database not responding, or timeout exceeded, it executes. * * Declarations: */ rtr_tid_t tid; rtr_uns_32_t select_idx; rtr_uns_32_t set_idx; rtr_qualifier_value_t select_qualifiers[8]; rtr_qualifier_value_t set_qualifiers[3]; /* Everyone has voted to accept the transaction, and RTR has told the * server to commit it. The client has moved on to performing the next * transaction. This transaction will be changed from `commit' status * to `exception' status for a later attempt at committing. * * Get the transaction id. The channel has previously been * declared in an rtr_open_channel call. */ rtr_get_tid(channel, RTR_F_TID_RTR, &tid); /* Load the rtr_qualifier_value_t structures that contain the * selection criteria for the transaction: `the transaction whose tid * is pointed at by `tid', whose facility name is in `facname', whose * partition name is in `partname', and whose transaction state is * `rtr_txn_jnl_commit' (logged to the journal as committed). */ select_idx = 0; select_qualifiers[select_idx].qv_qualifier = rtr_txn_tid; select_qualifiers[select_idx].qv_value = &tid; select_idx++; /* Facility name */ select_qualifiers[select_idx].qv_qualifier = rtr_facility_name; select_qualifiers[select_idx].qv_value = facname; select_idx++; /* Partition name */ select_qualifiers[select_idx].qv_qualifier = rtr_partition_name; select_qualifiers[select_idx].qv_value = partname; select_idx++; /* Transaction state in journal */ select_qualifiers[select_idx].qv_qualifier = rtr_txn_state; select_qualifiers[select_idx].qv_value = &rtr_txn_jnl_commit; select_idx++; /* Last one on array must be `rtr_qualifiers_end' */ select_qualifiers[ select_idx].qv_qualifier = rtr_qualifiers_end, select_qualifiers[ select_idx].qv_value = NULL; select_idx++; /* Load the * rtr_qualifier_t structs that we will use to set the * new property for the transaction: in this case, only the * state of the transaction. We will change it to * rtr_txn_jnl_exception, or `exception'. */ set_idx = 0; set_qualifiers[set_idx].qv_qualifier = rtr_txn_state; set_qualifiers[set_idx].qv_value = &rtr_txn_jnl_exception; set_idx++; /* Terminate the array with an rtr_qualifiers_end. */ set_qualifiers[set_idx].qv_qualifier = rtr_qualifiers_end; set_qualifiers[set_idx].qv_value = NULL; set_idx++; /* Tell RTR to change the transaction's state. */ status = rtr_set_info( &pchannel, RTR_NO_FLAGS, rtr_verb_set, rtr_transaction_object, select_qualifiers, set_qualifiers); check_status(status); /* The server should now look for an * RTR_STS_SETTRADONE message * from RTR, which confirms that it has changed the status. */

See Also

rtr_close_channel()
rtr_receive_message()
rtr_request_info()