DbEnv::set_rep_transport
|
|
#include <db_cxx.h>
int
DbEnv::set_rep_transport(int envid,
int (*send)(DB_ENV *dbenv,
const Dbt *control, const Dbt *rec, const DbLsn *lsnp,
int envid, u_int32_t flags));
Description: DbEnv::set_rep_transport
The DbEnv::set_rep_transport method initializes the communication infrastructure
for a database environment participating in a replicated application.
The DbEnv::set_rep_transport method configures operations performed using the specified
DbEnv handle, not all operations performed on the underlying
database environment.
The DbEnv::set_rep_transport method may be called at any time during the life of the
application.
The DbEnv::set_rep_transport method
either returns a non-zero error value
or throws an exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
Parameters
- envid
- The envid parameter is the local environment's ID. It must be
a positive integer and uniquely identify this Berkeley DB database environment
(see Replication environment IDs for more
information).
- send
- The send callback function is used to transmit data using the
replication application's communication infrastructure. The parameters
to send are as follows:
- dbenv
- The dbenv parameter is the enclosing database environment handle.
- control
- The control parameter is the first of the two data elements to be
transmitted by the send function.
- rec
- The rec parameter is the second of the two data elements to be
transmitted by the send function.
- lsnp
- If the type of message to be sent has an LSN associated with it, then
the lsnp parameter contains the LSN of the record being sent.
This LSN can be used to determine that certain records have been
processed successfully by clients.
- envid
- The envid parameter is a positive integer identifier that
specifies the replication environment to which the message should be
sent (see Replication environment IDs for
more information).
The special identifier DB_EID_BROADCAST indicates that a message
should be broadcast to every environment in the replication group. The
application may use a true broadcast protocol or may send the message
in sequence to each machine with which it is in communication. In both
cases, the sending site should not be asked to process the message.
- flags
- The flags parameter must be set to 0 or by bitwise inclusively OR'ing together one
or more of the following values:
- DB_REP_ANYWHERE
- The message is a client request that can be satisfied by another client
as well as by the master.
- DB_REP_NOBUFFER
- The record being sent should be transmitted immediately and not buffered
or delayed.
- DB_REP_PERMANENT
- The record being sent is critical for maintaining database integrity
(for example, the message includes a transaction commit). The
application should take appropriate action to enforce the reliability
guarantees it has chosen, such as waiting for acknowledgement from one
or more clients.
- DB_REP_REREQUEST
- The message is a client request that has already been made and to which
no response was received.
It may sometimes be useful to pass application-specific data to the
send function; see Environment
FAQ for a discussion on how to do this.
The send function should not call back down into Berkeley DB. The
send function must return 0 on success and non-zero on failure.
If the send function fails, the message being sent is necessary
to maintain database integrity, and the local log is not configured for
synchronous flushing, the local log will be flushed; otherwise, any
error from the send function will be ignored.
Errors
The DbEnv::set_rep_transport method
may fail and throw
DbException,
encapsulating one of the following non-zero errors, or return one of
the following non-zero errors:
- EINVAL
- An
invalid flag value or parameter was specified.
Class
DbEnv
See Also
Replication and Related Methods
Copyright (c) 1996-2005 Sleepycat Software, Inc. - All rights reserved.