Oracle DG 逻辑备库故障--MAX Processes
系统环境：
操作系统：RedHat EL6
Oracle： Oracle 11gR2
DataGuard 环境:
10:29:58 SYS@ test1>select dbid,name,database_role,protection_mode from v$database;
DBID NAME DATABASE_ROLE PROTECTION_MODE
---------- --------- ---------------- --------------------
1174898526 TEST1 PRIMARY MAXIMUM PERFORMANCE
10:30:06 SYS@ sh>select dbid,name,database_role,protection_mode from v$database;
DBID NAME DATABASE_ROLE PROTECTION_MODE
---------- --------- ---------------- --------------------
1675496824 SHDB LOGICAL STANDBY UNPROTECTED
10:28:11 SYS@ sh>alter database open;
Database altered.
Elapsed: 00:00:08.18
启动逻辑备库的redo log 应用：
10:28:29 SYS@ sh>alter database start logical standby apply immediate;
Database altered.
Elapsed: 00:00:00.30
10:28:40 SYS@ sh>
查看告警日志：altert.log:
ALTER DATABASE START LOGICAL STANDBY APPLY (sh)
Tue Apr 8 10:37:08 2014
with optional part
IMMEDIATE
LSP0 started with pid=19, OS id=3263
Tue Apr 8 10:37:08 2014
Attempt to start background Logical Standby process
LOGSTDBY Parameter: DISABLE_APPLY_DELAY =
LOGSTDBY Parameter: LOG_AUTO_DELETE = FALSE
LOGSTDBY Parameter: REAL_TIME =
Completed: alter database start logical standby apply immediate
Tue Apr 8 10:37:08 2014
LOGSTDBY status: ORA-16111: log mining and apply setting up
Tue Apr 8 10:37:08 2014
LOGMINER: Parameters summary for session# = 1
LOGMINER: Number of processes = 3, Transaction Chunk Size = 201
LOGMINER: Memory Size = 30M, Checkpoint interval = 150M
LOGMINER: session# = 1, builder process P001 started with pid=21 OS id=3267
LOGMINER: session# = 1, reader process P000 started with pid=20 OS id=3265
LOGMINER: session# = 1, preparer process P002 started with pid=22 OS id=3269
LOGSTDBY Analyzer process P003 started with pid=23 OS id=3271
LOGSTDBY Apply process P004 started with pid=24 OS id=3273
LOGSTDBY Apply process P006 started with pid=26 OS id=3277
LOGSTDBY Apply process P007 started with pid=27 OS id=3279
LOGSTDBY Apply process P008 started with pid=28 OS id=3281
LOGSTDBY Apply process P005 started with pid=25 OS id=3275
Tue Apr 8 10:41:33 2014
Redo Shipping Client Connected as PUBLIC
-- Connected User is Valid
RFS[1]: Assigned to RFS process 3295
RFS[1]: Identified database type as 'logical standby'
Tue Apr 8 10:41:33 2014
RFS LogMiner: Client enabled and ready for notification
RFS[1]: Archived Log: '/disk1/arch_sh/arch_1_36_797856158.log'
Tue Apr 8 10:41:33 2014
RFS LogMiner: Registered logfile [/disk1/arch_sh/arch_1_36_797856158.log] to LogMiner session id [1]
Tue Apr 8 10:41:33 2014
Redo Shipping Client Connected as PUBLIC
-- Connected User is Valid
RFS[2]: Assigned to RFS process 3297
RFS[2]: Identified database type as 'logical standby'
Tue Apr 8 10:41:33 2014
RFS LogMiner: Client enabled and ready for notification
RFS[2]: Archived Log: '/disk1/arch_sh/arch_1_35_797856158.log'
Tue Apr 8 10:41:33 2014
RFS LogMiner: Registered logfile [/disk1/arch_sh/arch_1_35_797856158.log] to LogMiner session id [1]
Tue Apr 8 10:41:34 2014
LOGMINER: Begin mining logfile: /disk1/arch_sh/arch_1_35_797856158.log
Tue Apr 8 10:41:34 2014
LOGMINER: End mining logfile: /disk1/arch_sh/arch_1_35_797856158.log
Tue Apr 8 10:41:34 2014
LOGMINER: Begin mining logfile: /disk1/arch_sh/arch_1_36_797856158.log
Tue Apr 8 10:41:34 2014
LOGMINER: End mining logfile: /disk1/arch_sh/arch_1_36_797856158.log
Tue Apr 8 10:43:26 2014
RFS[2]: Successfully opened standby log 4: '/u01/app/oracle/oradata/sh/std_redo04a.log'
Tue Apr 8 10:43:26 2014
RFS LogMiner: Client enabled and ready for notification
Tue Apr 8 10:43:26 2014
LOGMINER: Begin mining logfile: /u01/app/oracle/oradata/sh/std_redo04a.log
Tue Apr 8 10:43:26 2014
LOGMINER: End mining logfile: /u01/app/oracle/oradata/sh/std_redo04a.log
Tue Apr 8 10:43:26 2014
RFS LogMiner: Registered logfile [/disk1/arch_sh/arch_1_37_797856158.log] to LogMiner session id [1]
在备库上查看redolog 的应用：
11:00:27 SYS@ sh>select THREAD#,SEQUENCE#,APPLIED from dba_logstdby_log;
THREAD# SEQUENCE# APPLIED
---------- ---------- --------
1 31 YES
1 32 YES
1 33 YES
1 34 YES
1 35 YES
1 36 YES
1 37 YES
1 38 YES
1 39 YES
1 40 YES
10 rows selected.
在告警日志中出现以下，故障现象：
Errors in file /u01/app/oracle/admin/sh/bdump/sh_m000_3326.trc:
ORA-00018: maximum number of sessions exceeded
Tue Apr 8 10:50:29 2014
Errors in file /u01/app/oracle/admin/sh/bdump/sh_m000_3332.trc:
ORA-00018: maximum number of sessions exceeded
Tue Apr 8 10:51:29 2014
Errors in file /u01/app/oracle/admin/sh/bdump/sh_m000_3335.trc:
ORA-00018: maximum number of sessions exceeded
10:50:37 SYS@ sh>select count(*) from v$session;
解决问题：
1、查看当前process
10:51:11 SYS@ sh>show parameter process
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
aq_tm_processes integer 0
db_writer_processes integer 1
gcs_server_processes integer 0
job_queue_processes integer 0
log_archive_max_processes integer 3
processes integer 40
2、当前建立的session
10:51:11 SYS@ sh>select count（*） from v$session;
COUNT(*)
----------
29
当前Instance 的server process 采用dedicated 模式，当建立一个session时，需分配一个server process ；当前分配的server process 加上后台进程已经超过了max processes（40），所以需要增加max processes。
3、调整max processes 参数
10:53:19 SYS@ sh>alter system set processes=150 scope=spfile;
System altered.
重启Instance 后，参数生效.
10:55:40 SYS@ sh>show parameter process
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
aq_tm_processes integer 0
db_writer_processes integer 1
gcs_server_processes integer 0
job_queue_processes integer 0
log_archive_max_processes integer 3
processes integer 150
10:57:01 SYS@ sh>
@至此，问题解决