sqlnet.ora listener.ora tnsnames.ora

Database►Oracle Comments
$ORACLE_HOME/network/admin
sqlnet.ora(客户及服务器端)作用类似于linux或者其他unix的nsswitch.conf文件，通过这个文件来决定怎么样找一个连接中出现的连接字符串。
tnsnames.ora(客户及服务器端)类似于unix 的hosts文件，提供的tnsname到主机名或者ip的对应，只有当sqlnet.ora中类似NAMES.DIRECTORY_PATH= (TNSNAMES) 这样，也就是客户端解析连接字符串的顺序中有TNSNAMES时，才会尝试使用这个文件。
listener.ora(服务器端)listener监听器进程的配置文件。接受远程对数据库的接入申请并转交给oracle的服务器进程。所以如果不是使用的远程的连接，listener进程就不是必需的，同样的如果关闭listener进程并不会影响已经存在的数据库连接。
sqlplus / as sysdba典型的操作系统认证，不需要listener进程
sqlplus sys/oracle只能连接本机数据库，不需要listener进程
sqlplus sys/oracle@orcl需要listener进程处于可用状态。最普遍的通过网络连接。
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# 本地连接数据库，服务器进程显示如下：
ps -ef | grep LOCAL
oracle    2878  2814  0 09:46 ?        00:00:00   oracleorcl (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))

# 通过监听连接数据库，服务器进程显示如下
ps -ef | grep LOCAL
oracle    3124     1    0 09:48 ?         00:00:00 oracleorcl (LOCAL=NO)
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[grid@StandaloneOracle admin]$ echo $ORACLE_HOME
/u01/app/grid/product/11.2.0/grid
[grid@StandaloneOracle admin]$ pwd
/u01/app/grid/product/11.2.0/grid/network/admin
[grid@StandaloneOracle admin]$ cat sqlnet.ora 
# sqlnet.ora Network Configuration File: /u01/app/grid/product/11.2.0/grid/network/admin/sqlnet.ora
# Generated by Oracle configuration tools.

NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)

ADR_BASE = /u01/app/grid

[grid@StandaloneOracle admin]$ cat listener.ora
# listener.ora Network Configuration File: /u01/app/grid/product/11.2.0/grid/network/admin/listener.ora
# Generated by Oracle configuration tools.

LISTENER1 =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = StandaloneOracle)(PORT = 1522))
  )

ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER1 = ON

SID_LIST_LISTENER1 =
  (SID_LIST =
    (SID_DESC =
      (GLOBAL_DBNAME = susu)
      (ORACLE_HOME = /u01/app/grid/product/11.2.0/grid)
      (SID_NAME = orasidsusu)
    )
  )

ADR_BASE_LISTENER1 = /u01/app/grid

LISTENER =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = StandaloneOracle)(PORT = 1521))
  )

ADR_BASE_LISTENER = /u01/app/grid

ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER = ON

[grid@StandaloneOracle admin]$ 
[grid@StandaloneOracle admin]$ lsnrctl status

LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 07-DEC-2019 11:28:23

Copyright (c) 1991, 2009, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=StandaloneOracle)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 11.2.0.1.0 - Production
Start Date                07-MAY-2019 10:28:41
Uptime                    0 days 0 hr. 59 min. 42 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/grid/product/11.2.0/grid/network/admin/listener.ora
Listener Log File         /u01/app/grid/diag/tnslsnr/StandaloneOracle/listener/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=StandaloneOracle)(PORT=1521)))
Services Summary...
Service "+ASM" has 1 instance(s).
  Instance "+ASM", status READY, has 1 handler(s) for this service...
Service "orasidsusuXDB" has 1 instance(s).
  Instance "orasidsusu", status READY, has 1 handler(s) for this service...
Service "susu" has 1 instance(s).
  Instance "orasidsusu", status READY, has 1 handler(s) for this service...
The command completed successfully
[grid@StandaloneOracle admin]$ 
[grid@StandaloneOracle admin]$ lsnrctl status LISTENER1

LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 07-DEC-2019 11:30:16

Copyright (c) 1991, 2009, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=StandaloneOracle)(PORT=1522)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER1
Version                   TNSLSNR for Linux: Version 11.2.0.1.0 - Production
Start Date                07-DEC-2019 10:28:41
Uptime                    0 days 1 hr. 1 min. 35 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/grid/product/11.2.0/grid/network/admin/listener.ora
Listener Log File         /u01/app/grid/diag/tnslsnr/StandaloneOracle/listener1/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=StandaloneOracle)(PORT=1522)))
Services Summary...
Service "susu" has 1 instance(s).
  Instance "orasidsusu", status UNKNOWN, has 1 handler(s) for this service...
The command completed successfully
[grid@StandaloneOracle admin]$ 



[oracle@StandaloneOracle trace]$ tnsping susu

TNS Ping Utility for Linux: Version 11.2.0.1.0 - Production on 07-MAY-2019 11:26:06

Copyright (c) 1997, 2009, Oracle.  All rights reserved.

Used parameter files:
/u01/app/oracle/product/11.2.0/dbhome_1/network/admin/sqlnet.ora


Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = StandaloneOracle)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = susu)))
OK (0 msec)
[oracle@StandaloneOracle trace]$

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