Reliable Transaction Router
C Application Programmer's
Reference Manual


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rtr_reject_tx

Reject the transaction currently active on a channel.

Syntax

status = rtr_reject_tx (channel, flags, reason)

Argument Data Type Access
status rtr_status_t write
channel rtr_channel_t read
flags rtr_rej_flag_t read
reason rtr_reason_t read


C Binding

rtr_status_t rtr_reject_tx (


rtr_channel_t channel ,
rtr_rej_flag_t flags ,
rtr_reason_t reason
)


Arguments

channel

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

flags

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

reason

The reason for the rejection. This rejection reason is returned to the other participants in the transaction. It is returned in the reason field of the structure rtr_status_data_t with the rtr_mt_rejected message. Specify RTR_NO_REASON if no reason is to be supplied.

Description

The rtr_reject_tx() call rejects the transaction that is active on the specified channel.

When rtr_reject_tx() returns, the channel is no longer associated with the transaction.

Once an rtr_accept() has been called by the server application, the rtr_reject_tx() call is not allowed until the first message of the next transaction is received. An attempt to call rtr_reject_tx() yields an RTR_STS_TXALRACC return status.

Return Value A value indicating the status of the routine. Possible status values are:
RTR_STS_DLKTXRES 1 Deadlock detected, transaction rescheduled
RTR_STS_INVCHANNEL Invalid channel argument
RTR_STS_INVFLAGS Invalid flags argument
RTR_STS_NOCURROU No router currently available for this frontend
RTR_STS_NOSRVAVL Service not yet available
RTR_STS_OK Normal successful completion
RTR_STS_TXALRACC Transaction already accepted
RTR_STS_TXNOTACT No transaction currently active on this channel

1This status is returned to a client in the status field of a message of type rtr_mt_rejected if a transaction currently being processed has been aborted because of a deadlock with other transactions using the same servers. RTR replays the transaction after the deadlock has been cleared. This condition can be caused by either a classic database deadlock or a potential deadlock that RTR tries to avoid in cases such as concurrent server death or server role change. For more details, see the section in the RTR Application Design Guide, Handling Error Conditions.

Example


rtr_uns_32_t MT_LAST_NAME = 678; 
          /* Defined in user's .h file. */ 
 
if (last_name == null) 
{ 
/* Missing last name! Not everything is ready for 
 * committing the current transaction (e.g., through 
 * validations), and so wishes to reject it, rather than 
 * to commit it. 
 */ 
           status = rtr_reject_tx( 
                   &channel,          
                   // Same channel it came in on. 
                   RTR_F_REJ_RETRY,   
                   // Retry from msg1 of txn. 
           MT_LAST_NAME );            
                  // User-defined error code. 
 
        check_status(status); 
        return; 
        } 

See Also

rtr_open_channel()
rtr_accept_tx()

rtr_reply_to_client

Send a server's reply to a client's transactional message.

Syntax

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

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


C Binding

rtr_status_t rtr_reply_to_client (


rtr_channel_t channel ,
rtr_rep_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 3-10 shows the flags defined for this call.

Table 3-10 Reply To Client Flag
Flag Description
RTR_F_REP_ACCEPT The transaction is accepted by this server. This is equivalent to sending a reply to the server and immediately following it with a call to rtr_accept_tx() . This is useful in those cases where the sender knows that the transaction is definitely acceptable.
RTR_F_REP_FORGET Set to prevent receipt of any more messages or completion status associated with the transaction after it has been accepted. Using this flag requires that the RTR_F_ACC_FORGET flag be set in the rtr_accept_tx call, indicating that the transaction is to be accepted.
RTR_F_REP_INDEPENDENT Set to indicate that this transaction is independent; can only be used with RTR_F_REP_ACCEPT . (See Section 2.16.4, Transaction Independence, for further information.)

Specify RTR_NO_FLAGS for this parameter if no flags are required.

pmsg

Pointer to the reply message to be sent.

msglen

Length of the message to be sent, in bytes.

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 2.15, 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 other hardware platforms will not be used.


Description

The rtr_reply_to_client() call sends a transactional message back to the client that started the transaction.

The caller must first obtain a server channel (using the rtr_open_channel() call) and must have received a message from a client using the rtr_receive_message() call.

Once an rtr_accept_tx() has been called by the server application, the rtr_reply_to_client() call is not allowed until the first message of the next transaction is received. An attempt to call rtr_reply_to_client() yields an RTR_STS_TXALRACC return status.

Return Value A value indicating the status of the routine. Possible status values are:
RTR_STS_INSVIRMEM Insufficient virtual memory
RTR_STS_INVCHANNEL Invalid channel argument
RTR_STS_INVFLAGS Invalid flags argument
RTR_STS_INVMSGFMT Invalid msgfmt argument
RTR_STS_INVMSGLEN Invalid msglen argument
RTS_STS_NOCURROU No router currently available for this frontend
RTR_STS_NOSRVAVL Service not yet available
RTR_STS_OK Normal successful completion
RTR_STS_TXALRACC Transaction already accepted
RTR_STS_TXNOTACT No transaction currently active on this channel

Example


/* The purchase_msg structure is defined in the user's 
 * application header file. 
 */ 
typedef struct { 
                rtr_uns_8_t     my_msg_type; 
                string31        last_name; 
                rtr_uns_32_t    order_total; 
                rtr_uns_32_t    shipping_amt; 
                string7         user_id; 
} purchase_msg; 
 
purchase_msg purch_msg; 
 
/* The client has made a request on the server; the server 
 * has fulfilled this request, and now needs to let the 
 * client know the result. 
 * 
 * In this case, the client has asked the server to total 
 * the purchases in the user's shopping cart. The server 
 * is accepting the transaction at this time as well, without 
 * being explicitly asked to. 
 
 */ 
purch_msg.my_msg_type = MY_TOTAL_PURCHASES; 
purch_msg.last_name = cust_last_name; 
. 
.       Fill the struct based on database query or calculations. 
. 
status = rtr_reply_to_client ( 
                            channel, 
                            RTR_F_REP_ACCEPT, 
                            &purch_msg, 
                            sizeof(purch_msg), 
                            RTR_NO_MSGFMT); 
 
        check_status(status); 

See Also

rtr_receive_message()
rtr_open_channel()
rtr_accept_tx()

rtr_request_info

Request information about the RTR environment.

Syntax

status = rtr_request_info (pchannel, flags, infcla, selitm, selval, getitms)

Argument Data Type Access
status rtr_status_t write
pchannel rtr_channel_t write
flags rtr_req_flag_t read
infcla rtr_infoclass_t read
selitm rtr_itemcode_t read
selval rtr_selval_t read
getitms rtr_itemcode_t read


C Binding

rtr_status_t rtr_request_info (


rtr_channel_t *pchannel ,
rtr_req_flag_t flags ,
rtr_infoclass_t infcla ,
rtr_itemcode_t selitm ,
rtr_selval_t selval ,
rtr_itemcode_t getitms
)


Arguments

pchannel

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

flags

No flags are defined for this call. Use RTR_NO_FLAGS for this parameter.

infcla

A null-terminated text string that specifies the type of information for which data are requested. Table 3-11 lists information types and their specifying information class strings. Within an information class, you retrieve a specific datum with selitm, selval, and getitms parameters specified as strings. Data returned by rtr_request_info are valid only under certain conditions as listed in Table 3-11. For example, to obtain information about a node, use the "rtr" string; RTRACP must be running for data to be valid.

Table 3-11 Information Classes
For this type of information: Use this Information Class string: For valid data: For available items and strings, see:
Application process prc An application process must have been started ( rtr_open_channel called). Table 3-12
Client process cli A client channel must have been opened. Table 3-13
Facility fac A facility must be defined. Table 3-14
Key segment ksg A server channel must have been opened. Table 3-15
Link to a node lnk A facility must be defined. Table 3-16
Node or RTRACP rtr RTRACP must be running. Table 3-17
Partition on a backend bpt A server channel must have been opened. Table 3-18
Partition on a router rpt A server channel must have been opened. Table 3-19
Partition history hpt A server channel must have been opened. Table 3-20
Server process srv A server channel must have been opened. Table 3-21
Transaction on a backend btx A transaction must be in progress on the backend. Table 3-22
Transaction on a frontend ftx A client application must have a transaction in progress. Table 3-23
Transaction on a router rtx A transaction must be in progress on the router. Table 3-24

selitm

Null-terminated text string giving the strings used to select information such as facility name or transaction ID. Use this argument to reduce the amount of information returned. If you specify a null string (""), all available information for the class is returned. A string containing multiple items should be a comma-separated list. Some SHOW commands display the same data. For example, to obtain the RTR version number (displayed by SHOW RTR/VERSION ), use the string rtr_version_string from the "rtr" information class.

Table 3-12 Application Process ("prc") Strings
For this selitm: Use this string:
Process-id process_id
Process Name process_name

Table 3-13 Client Process ("cli") Strings
For this selitm: Use this string:
Process-id dpb_pid
Facility fdb_f_name
Channel dpb_chan
Flags dpb_dclflg
State dpb_req_sts
rcpnam dpb_evtnam
User Events dpb_user_evtnum
RTR Events dpb_rtr_evtnum

Table 3-14 Facility ("fac") Strings
For this selitm: Use this string:
Facility fdb_f_name
Frontend fdb_attr.fdb_attr_bits.is_fe
Router fdb_attr.fdb_attr_bits.is_rtr
Backend fdb_attr.fdb_attr_bits.is_be
Reply Checksum fdb_attr.fdb_attr_bits.reply_enabled
Router call-out fdb_attr.fdb_attr_bits.tr_call_out
Backend call-out fdb_attr.fdb_attr_bits.be_call_out
Load balance fdb_attr.fdb_attr_bits.feshare
Quorum-check off fdb_attr.fdb_attr_bits.qrt_chk
FE -> TR fdb_trsrch
Router quorate fdb_state.fdb_state_bits.tr_qrt
Backend quorate fdb_state.fdb_state_bits.be_qrt
Quorum threshold fdb_iqt_cnt
Min bcst rate fdb_cn_fct_min_brd_out_rate
Frontends connected fdb_fecnt
Frontends allowed fdb_fecdt
Load coordinator fdb_status.fdb_status_bits.qm_be
Quorate routers fdb_trtot
Total Frontends fdb_fetot
Current Credit fdb_curcdt
FE -> TR fdb_trsrch
Link to fac_ndb
Frontend fac_fe.rol_bits.rol_cfg
Router fac_tr.rol_bits.rol_cfg
Backend fac_be.rol_bits.rol_cfg
Router -> Frontend fac_reasons.fac_reason_bits.trfelnk
Frontend -> Router fac_reasons.fac_reason_bits.fetrlnk
Backend -> Router fac_reasons.fac_reason_bits.betrlnk
Router -> Backend fac_reasons.fac_reason_bits.trbelnk
Router quorate fac_tr.rol_bits.rol_quorum
Backend -> Router fac_reasons.fac_reason_bits.betrlnk
Router -> Backend fac_reasons.fac_reason_bits.trbelnk
Router quorate fac_tr.rol_bits.rol_quorum
Backend quorate fac_be.rol_bits.rol_quorum
Router current fac_tr.rol_bits.rol_cur
Backend coordinator fac_be.rol_bits.rol_qmaster

Table 3-15 Key Segment ("ksg") Strings
For this selitm: Use this string:
Facility fdb_f_name
Data Type ksd_dtyp
Length ksd_length
Offset ksd_offset

Table 3-16 Node Links ("lnk") Strings
For this selitm: Use this string:
To Node ndb_name
Address ndb_idp
Outgoing message sequence nr ndb_xcnt
Incoming message sequence nr ndb_rcnt
Current receive buffer size ndb_credit
Current transmit buffer size ndb_cdt_out
Current number of link users ndb_reasons
Write buffer timed out ndb_status.wbuftmo
Write buffer full, may be sent ndb_status.wbufrdy
Write buffer allocated ndb_status.wbufalc
I/O error detected in write ndb_status.wrerror
I/O error detected in read ndb_status.rderror
Pipe temporarily blocked ndb_status.blocked
Connection broken ndb_status.aborted
Write issued, not completed ndb_status.writing
Read is pending ndb_status.reading
Node initiated the connection ndb_status.initiator
Connection established ndb_status.connected
Connection in progress ndb_status.connecting
Node is configured ndb_status.configured
Autoisolation enabled ndb_attr.attr_bits.isol_ebld
Link disabled ndb_attr.attr_bits.disabled
Link isolated ndb_attr.attr_bits.isolated
In facility fac_ifn
Frontend fac_fe.rol_bits.rol_cfg
Router fac_tr.rol_bits.rol_cfg
Backend fac_be.rol_bits.rol_cfg
Router -> Frontend fac_reasons.fac_reason_bits.trfelnk
Frontend -> Router fac_reasons.fac_reason_bits.fetrlnk
Backend -> Router fac_reasons.fac_reason_bits.betrlnk
Router -> Backend fac_reasons.fac_reason_bits.trbelnk
Router quorate fac_tr.rol_bits.rol_quorum
Backend quorate fac_be.rol_bits.rol_quorum
Router current fac_tr.rol_bits.rol_cur
Backend coordinator fac_be.rol_bits.rol_qmaster

Table 3-17 Node and ACP ("rtr") Strings
For this selitm: Use this string:
Network state ncf_isolated
Auto isolation ncf_isol_ebld
Inactivity timer/s ncf_lw_inact
RTR Version Number rtr_version_string

Table 3-18 Partition on a Backend ("bpt") Strings
For this selitm: Use this string:
Partition name $name
Facility ppb_fdbptr
State ppb_pst.prt_ps
Low Bound ppb_krd.krd_low_bound
High Bound ppb_krd.krd_high_bound
Active Servers srb_active_q.#crm_server_block
Free Servers srb_free_q.#crm_server_block
Transaction presentation tx_presentation_state
Last Rcvy BE last_lcl_rec_be
Txns Active tkb_q.#crm_tx_kr_block
Txns Rcvrd rec_be_txs
Failover policy ppb_failover_policy
Key range ID ppb_krid

Table 3-19 Partition on a Router ("rpt") Strings
For this selitm: Use this string:
Facility fdb_f_name
State krb_sts
Low Bound krb_low_bound
High Bound krb_high_bound
Failover policy krb_failover_policy
Backends bpsb_ndbptr
States bpsb_pst.prt_ps
Primary Main krb_pri_act_bpsbptr.bpsb_ndbptr
Shadow Main krb_sec_act_bpsbptr.bpsb_ndbptr

Table 3-20 Partition History ("hpt") Strings
For this selitm: Use this string:
Partition name $name
Facility phr_fdb
Low Bound phr_krd.krd_low_bound
High Bound phr_krd.krd_high_bound
Creation time phr_creation_time

Table 3-21 Server Process ("srv") Strings
For this selitm: Use this string:
Process-id dpb_pid
Facility fdb_f_name
Channel dpb_chan
Flags dpb_dclflg
State ppb_pst.prt_ps
Low Bound ppb_krd.krd_low_bound
High Bound ppb_krd.krd_high_bound
rcpnam dpb_evtnam
User Events dpb_user_evtnum
RTR Events dpb_rtr_evtnum
Partition-Id dpb_krid

Table 3-22 Transaction on a Backend ("btx") Strings
For this selitm: Use this string:
Tid tb_txdx.tx_id
Facility fac_id
FE-User tb_txdx.fe_user
State state
Start time tb_txdx.tx_start_time
Router tr_ndbptr
Invocation invocation
Active-Key-Ranges #crm_tx_kr_block
Recovering-Key-Ranges #crm_tr_block
Total-Tx-Enqs nr_tx_enqs
Key-Range-Id kr_id
Server-Pid pid
Server-State sr_state
Journal-Node jnl_node_id
Journal-State jnl_state
First-Enq first_enq_nr
Nr-Enqs nr_enqs
Nr-Replies nr_replys

Table 3-23 Transaction on a Frontend ("ftx") Strings
For this selitm: Use this string:
Tid tb_txdx.tx_id
Facility fac_id
FE-User tb_txdx.fe_user
State state
Start time tb_txdx.tx_start_time
Router tr_ndbptr
Nr-Enqs enqs_from_rq
Nr-Replies replys_rcvd

Table 3-24 Transaction on a Router ("rtx") Strings
For this selitm: Use this string:
Tid tb_txdx.tx_id
Facility fac_id
FE-User tb_txdx.fe_user
State state
Start time tb_txdx.tx_start_time
FE-Connected fe_ndbptr
Total-Tx-Enqs nr_tx_enqs
First-Enq first_enq_nr
Nr-Enqs nr_enqs
Backend be_ndbptr
Key-Range-State kr_state
Key-Range-Id kr_id
Journal-State be_state

selval

Null-terminated text string; contains a value for the item named in selitm. For example, if selitm specifies fac_id indicating that a facility name is used for the selection, and selval contains the string "TESTFAC", then only information for facility TESTFAC is returned. Wildcards can be used in this specification.

getitms

Null-terminated text string containing a comma-separated list of items whose values are returned. For each instance that matches the selection criterion, the values of the items specified by getitms are returned in a message of type rtr_mt_request_info .

Description

An application program can use the rtr_request_info() call to interrogate the RTR environment and retrieve information about facilities, transactions, key ranges, and so on. The call accesses data maintained by RTR on behalf of application programs, and data maintained by the RTR ACP itself.


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