Berkeley DB: DbEnv::rep_process_message
Description: Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++

# DbEnv::rep_process_message |

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    #include <db_cxx.h>

    int
    DbEnv::rep_process_message(Dbt *control, Dbt *rec, int *envid)

# Description

The DbEnv::rep_process_message method processes an incoming replication message sent by a member of the replication group to the local database environment.

The rec and control parameters should reference a copy of the parameters specified by Berkeley DB for the rec and control parameters on the sending environment.

The envid parameter should contain the local identifier that corresponds to the environment that sent the message to be processed (see Replication environment IDs for more information).

For implementation reasons, all incoming replication messages must be processed using the same DbEnv handle. It is not required that a single thread of control process all messages, only that all threads of control processing messages use the same handle.

The DbEnv::rep_process_message method may return one of several special conditions:

DB_REP_DUPMASTER
  The replication group has more than one master; the application should reconfigure itself as a client by calling the DbEnv::rep_start method, and then call for an election by calling DbEnv::rep_elect.

DB_REP_HOLDELECTION
  An election is needed, the application should call for an election by calling DbEnv::rep_elect.

DB_REP_NEWMASTER
  A new master has been elected. The memory location referenced by the envid parameter contains the environment ID of the new master. If the recipient of this error return has been made master, it is the application's responsibility to begin acting as the master environment.

DB_REP_NEWSITE
  The system received contact information from a new environment. The rec parameter contains the opaque data specified in the cdata parameter to the DbEnv::rep_start. The application should take whatever action is needed to establish a communication channel with this new environment.

DB_REP_OUTDATED
  The current environment's logs are too far out of date with respect to the master to be automatically synchronized. The application should copy over a hot backup of the environment, run recovery, and restart the client.

Otherwise, the DbEnv::rep_process_message 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.

# Errors

The DbEnv::rep_process_message method may fail and throw an exception or return a non-zero error for errors specified for other Berkeley DB and C library or system methods. If a catastrophic error has occurred, the DbEnv::rep_process_message method may fail and either return DB_RUNRECOVERY or throw an exception encapsulating DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail in the same way.

# See Also

DbEnv::rep_start, DbEnv::rep_elect, DbEnv::rep_process_message, and DbEnv::set_rep_transport.`

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