一、环境
12c ADG环境

二、现象描述

主库日志切换卡住（hang）

SQL> alter system switch logfile;

三、处理过程
1、查看日志

$tail -f al*.log
Mon Jan 08 21:04:20 2018
ARC0: LGWR is scheduled to archive destination LOG_ARCHIVE_DEST_1 after log switch
Mon Jan 08 21:11:21 2018
ARC3: LGWR is scheduled to archive destination LOG_ARCHIVE_DEST_1 after log switch
Mon Jan 08 21:19:21 2018
ARC0: LGWR is scheduled to archive destination LOG_ARCHIVE_DEST_1 after log switch
Mon Jan 08 21:26:22 2018
ARC3: LGWR is scheduled to archive destination LOG_ARCHIVE_DEST_1 after log switch
Mon Jan 08 21:34:22 2018
ARC0: LGWR is scheduled to archive destination LOG_ARCHIVE_DEST_1 after log switch
Mon Jan 08 21:42:19 2018
ARC0: LGWR is scheduled to archive destination LOG_ARCHIVE_DEST_1 after log switch

2、考虑归档参数

SQL> show parameter log_archive_dest

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest                     string
log_archive_dest_1                   string      service="orcl", SYNC AFFIRM de
                                                 lay=0 optional compression=dis
                                                 able max_failure=0 max_connect
                                                 ions=1 reopen=300 db_unique_na
                                                 me="orcl" net_timeout=10, vali
                                                 d_for=(online_logfile,all_role
                                                 s)
log_archive_dest_10                  string
log_archive_dest_11                  string
log_archive_dest_12                  string

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_13                  string
log_archive_dest_14                  string
log_archive_dest_15                  string
log_archive_dest_16                  string
log_archive_dest_17                  string
log_archive_dest_18                  string
log_archive_dest_19                  string
log_archive_dest_2                   string      location="+DATADG/arch",  vali
                                                 d_for=(STANDBY_LOGFILE,STANDBY
                                                 _ROLE)

3、参数明显有问题,另开一个会话

SQL> ALTER SYSTEM SET log_archive_dest_2='location="+DATADG/arch",  valid_for=(ALL_LOGFILES,ALL_ROLES)';

System altered.

SQL>

4、查看主库日志

ALTER SYSTEM SET log_archive_dest_2='location="+DATADG/arch",  valid_for=(ALL_LOGFILES,ALL_ROLES)' SCOPE=BOTH;
Mon Jan 08 21:49:23 2018
Archived Log entry 376 added for thread 1 sequence 365 ID 0x58e622f8 dest 2:
krse_arc_driver_core: Successful archiving of previously failed ORL
Mon Jan 08 21:49:23 2018
******************************************************************
LGWR: Setting 'active' archival for destination LOG_ARCHIVE_DEST_1
******************************************************************
Mon Jan 08 21:49:24 2018
Destination LOG_ARCHIVE_DEST_1 no longer supports SYNCHRONIZATION
Mon Jan 08 21:49:24 2018
Thread 1 advanced to log sequence 368 (LGWR switch)
  Current log# 1 seq# 368 mem# 0: +DATADG/ORCLDG/ONLINELOG/group_1.399.962961189
  Current log# 1 seq# 368 mem# 1: +DATADG/ORCLDG/ONLINELOG/group_1.402.962961189
Mon Jan 08 21:49:24 2018
Archived Log entry 377 added for thread 1 sequence 366 ID 0x58e622f8 dest 2:
Mon Jan 08 21:49:24 2018
Archived Log entry 378 added for thread 1 sequence 367 ID 0x58e622f8 dest 2:
Mon Jan 08 21:49:48 2018
Destination LOG_ARCHIVE_DEST_1 is SYNCHRONIZED
Mon Jan 08 21:49:49 2018
Destination LOG_ARCHIVE_DEST_1 no longer supports SYNCHRONIZATION
Mon Jan 08 21:49:49 2018
Thread 1 advanced to log sequence 369 (LGWR switch)
  Current log# 2 seq# 369 mem# 0: +DATADG/ORCLDG/ONLINELOG/group_2.401.962961191
  Current log# 2 seq# 369 mem# 1: +DATADG/ORCLDG/ONLINELOG/group_2.404.962961191
Mon Jan 08 21:49:49 2018
Archived Log entry 383 added for thread 1 sequence 368 ID 0x58e622f8 dest 2:

5、小结
要理解本地归档路径参数的具体含义