Which statement is true about Oracle Net Listener?
A.It acts as the listening endpoint for the Oracle database instance for all local and non-local user connections.
B.A single listener can service only one database instance and multiple remote client connections.
C.Service registration with the listener is performed by the process monitor (PMON) process of each database instance.
D.The listener.ora configuration file must be configured with one or more listening protocol addresses to allow remote users to connect to a database instance.
E.The listener.ora configuration file must be located in the ORACLE_HOME/network/admin directly.
when i pass exam there was a correct question with lreg (not pmon) process
Listener Registration Process (LREG)
The listener registration process (LREG) registers information about the database instance and dispatcher processes with the Oracle Net Listener (see “The Oracle Net Listener”). When an instance starts, LREG polls the listener to determine whether it is running. If the listener is running, then LREG passes it relevant parameters. If it is not running, then LREG periodically attempts to contact it.
C. Service registration with the listener is performed by the process monitor (LREG) process of each database instance.
but i took question from aiotestking and try to check all answers ^_^ so from all incorrect answers more correct is:
Answer: E
A.False as we can connect to database as local user bypassing the listener
[code language=”sql” highlight=”2,3,4,10,11,12″]
[oracle@oel6-6 ~]$ lsnrctl services | grep established
"DEDICATED" established:0 refused:0 state:ready
"DEDICATED" established:0 refused:0 state:ready
"D000" established:0 refused:0 current:0 max:1022 state:ready
[oracle@oel6-6 ~]$ sqlplus / as sysdba
…
SQL> exit
[oracle@oel6-6 ~]$ lsnrctl services | grep established
"DEDICATED" established:0 refused:0 state:ready
"DEDICATED" established:0 refused:0 state:ready
"D000" established:0 refused:0 current:0 max:1022 state:ready
[/code]
B. False, as single grid listener serve rdbms database instance
C. False, there are new BG process LREG – Listener Registration Process ( Registers the instance with the listeners )
D. FALSE
Configuring Dynamic Service Registration
Service registration allows processes, such as an Oracle database, to identify their available services to the listener, which then acts as a port mapper for those services. The listener uses the dynamic service information about the database and instance received through service registration.
Dynamic service registration is configured in the database initialization file. It does not require any configuration in the listener.ora file. However, listener configuration must be set to listen on the ports named in the database initialization file, and must not have parameters set that prevent automatic registration, such as COST parameters.
+
Registering Information with a Local Listener
By default, the LREG process registers service information with its local listener on the default local address of TCP/IP, port 1521. If the listener configuration is synchronized with the database configuration, then LREG can register service information with a nondefault local listener or a remote listener on another node. Synchronization occurs when the protocol address of the listener is specified in the listener.ora file and the location of the listener is specified in the initialization parameter file.
there is no config file in database $ORACLE_HOME but it start and works fine:
[code language=”sql”]
[grid@oel7-3 ~]$ lsnrctl stop
[oracle@oel7-3 ~]$ ls $ORACLE_HOME/network/admin | grep listener | wc -l
ls: cannot access /network/admin: No such file or directory
0
[oracle@oel7-3 ~]$ lsnrctl start
[oracle@oel7-3 ~]$ lsnrctl status
LSNRCTL for Linux: Version 12.1.0.2.0 – Production on 10-OCT-2015 22:55:19
Copyright (c) 1991, 2014, Oracle. All rights reserved.
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
————————
Alias LISTENER
Version TNSLSNR for Linux: Version 12.1.0.2.0 – Production
Start Date 10-OCT-2015 22:55:05
Uptime 0 days 0 hr. 0 min. 16 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Log File /ora01/app/oracle/diag/tnslsnr/oel7-3/listener/alert/log.xml
Listening Endpoints Summary…
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=oel7-3)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcps)(HOST=oel7-3)(PORT=5500))(Security=(my_wallet_directory=/ora01/app/oracle/product/12.1.0.2/admin/p00db1/xdb_wallet))(Presentation=HTTP)(Session=RAW))
Services Summary…
Service "p00db1" has 1 instance(s).
Instance "p00db1", status READY, has 1 handler(s) for this service…
Service "p00db1XDB" has 1 instance(s).
Instance "p00db1", status READY, has 1 handler(s) for this service…
Service "pdb1" has 1 instance(s).
Instance "p00db1", status READY, has 1 handler(s) for this service…
Service "sw" has 1 instance(s).
Instance "p00db1", status READY, has 1 handler(s) for this service…
The command completed successfully
[/code]
E. TRUE