Multi-processes on the same machine open the same database

Question

I run into an issue where I have two processes, running on the same machine.
Process-1 starts the replication as master and opens database for read-write.
Process-2 only opens the same database for read-write, no replication is started,
and process-2 will fail to open the database because of "Non-replication DB_ENV
handle attempting to modify a replicated environment" error.
Can you suggest a way to handle this scenario?
Can two processes on the same machine open the same database for read-write?
Thanks.

Answer 1

Following are how I setup the database environment for Master side:
DB_ENV->rep_set_priority(80)
DB_ENV->repmgr_set_ack_policy(DB_REPMGR_ACKS_ALL)
DB_ENV->repmgr_set_local_site()
DB_ENV->rep_set_nsites(2)
DB_ENV->set_cachesize(1MB)
DB_ENV->set_data_dir()
DB_ENV->set_lg_dir()
DB_ENV->set_tmp_dir()
DB_ENV->set_flags(DB_AUTO_COMMIT, 1)
DB_ENV->set_lg_max(1MB)
DB_ENV->log_set_config(DB_LOG_AUTO_REMOVE, 1)
DB_ENV->set_lg_bsize(1MB)
openFlags = DB_INIT_MPOOL | DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_TXN | DB_INIT_REP | DB_THREAD | DB_CREATE | DB_USE_ENVIRON;
DB_ENV->open("/home/db", openFlags, 0644)
DB_ENV->repmgr_start(3 threads, DB_REP_MASTER)
Both processes using the same environment home directory.
Now I'm able to get both process up and running, because now I check for DB_REP_IGNORE return value from repmgr_start() method on the second process.
The first process starts the replication server, and the second process will not start the replication server at all.
However, if the first process terminated and got restart, the replication server will not be restarted...
I saw there's a check of "listener" in the repmgr_start function.
How can I restart the replication server either upon restarting the first process or from the running second process?