本文档风哥主要介绍Oracle ORA-27101共享内存不存在相关知识，包括ORA-27101的概念、ORA-27101的常见原因、ORA-27101分析方法、ORA-27101错误分析配置、ORA-27101错误监控、ORA-27101错误故障处理等内容，由风哥教程参考Oracle官方文档Troubleshooting内容编写，适合DBA人员在学习和测试中使用，如果要应用于生产环境则需要自行确认。
Part01-基础概念与理论知识
1.1 ORA-27101的概念
Oracle ORA-27101是Oracle数据库的共享内存不存在错误，表示共享内存区域不存在或无法访问。ORA-27101错误通常与ORA-01034错误一起出现，表示数据库实例未启动或共享内存段已被删除。ORA-27101错误需要启动数据库实例或检查共享内存配置。更多视频教程www.fgedu.net.cn
- 共享内存不存在：共享内存区域不存在
- 实例未启动：数据库实例未启动
- 内存段被删除：共享内存段已被删除
- 权限问题：共享内存权限问题
- 系统资源不足：系统内存资源不足
1.2 ORA-27101的常见原因
Oracle ORA-27101的常见原因：
- 实例未启动：数据库实例未启动
- 实例崩溃：数据库实例崩溃
- 共享内存被删除：共享内存段被手动删除
- ORACLE_SID错误：ORACLE_SID环境变量设置错误
- 权限问题：共享内存权限不足
- 系统内存不足：系统内存资源不足
- 内核参数错误：内核参数配置错误
1.3 ORA-27101分析方法
Oracle ORA-27101分析方法：
- 错误信息分析：分析错误信息含义
- 共享内存分析：分析共享内存状态
- 实例状态分析：分析数据库实例状态
- 环境变量分析：分析Oracle环境变量
- 内核参数分析：分析内核参数配置
- 告警日志分析：分析告警日志
Part02-生产环境规划与建议
2.1 ORA-27101错误处理规划
Oracle ORA-27101错误处理规划要点：
– 错误监控：监控ORA-27101错误发生
– 错误记录：记录ORA-27101错误信息
– 错误分析：分析ORA-27101错误原因
– 错误处理：处理ORA-27101错误问题
# 错误监控规划
– 监控工具：选择监控工具
– 监控频率：设置监控频率
– 监控范围：定义监控范围
– 告警配置：配置告警规则
# 错误记录规划
– 记录方式：选择记录方式
– 记录格式：定义记录格式
– 记录保留：设置记录保留时间
– 记录备份：备份错误记录
# 错误分析规划
– 分析方法：选择分析方法
– 分析工具：选择分析工具
– 分析流程：定义分析流程
– 分析报告：生成分析报告
# 错误处理规划
– 处理流程：定义处理流程
– 处理优先级：设置处理优先级
– 处理责任人：指定处理责任人
– 处理验证：验证处理结果
2.2 ORA-27101错误分析工具
Oracle ORA-27101错误分析工具：
- SQL*Plus：命令行工具
- SQL Developer：图形化工具
- Enterprise Manager：企业级管理工具
- ipcs：共享内存查看工具
- ipcrm：共享内存删除工具
- sysctl：内核参数配置工具
– SQL*Plus：快速查询错误信息
– SQL Developer：图形化分析错误
– Enterprise Manager：集中管理错误
– ipcs：查看共享内存状态
– ipcrm：删除共享内存段
– sysctl：配置内核参数
2.3 ORA-27101错误处理最佳实践
Oracle ORA-27101错误处理最佳实践：
- 定期监控：定期监控ORA-27101错误
- 及时处理：及时处理ORA-27101错误
- 文档记录：记录错误处理过程
- 经验积累：积累错误处理经验
- 预防措施：制定预防措施
Part03-生产环境项目实施方案
3.1 ORA-27101错误分析配置
3.1.1 配置共享内存管理
$ ipcs -m
—— Shared Memory Segments ——–
key shmid owner perms bytes nattch status
0x00000000 1234567890 oracle 600 5368709120 50
0x00000000 1234567891 oracle 600 5368709120 50
# 2. 查看特定Oracle用户的共享内存
$ ipcs -m | grep oracle
0x00000000 1234567890 oracle 600 5368709120 50
0x00000000 1234567891 oracle 600 5368709120 50
# 3. 查看内核参数
$ sysctl -a | grep kernel.shm
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
# 4. 查看内核参数配置文件
$ cat /etc/sysctl.conf | grep shm
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
# 5. 修改内核参数
$ vi /etc/sysctl.conf
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
# 6. 使内核参数生效
$ sysctl -p
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
# 7. 查看数据库实例状态
$ ps -ef | grep ora_pmon
oracle 12345 1 0 09:00 ? 00:00:00 ora_pmon_FGEDUDB
# 8. 查看Oracle环境变量
$ echo $ORACLE_SID
FGEDUDB
$ echo $ORACLE_HOME
/oracle/app/oracle/product/19c/dbhome_1
# 9. 测试数据库连接
$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 – Production on Mon Mar 31 10:00:00 2026
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 – Production
Version 19.3.0.0.0
SQL> select instance_name, status, database_status, startup_time
from v$instance;
INSTANCE_NAME STATUS DATABASE_STATUS STARTUP_TIME
—————- ———— —————– ——————-
FGEDUDB OPEN ACTIVE 31-MAR-26 09:00:00
3.1.2 配置共享内存自动清理
$ vi /home/oracle/scripts/clean_shared_memory.sh
#!/bin/bash
# from:www.itpux.com.qq113257174.wx:itpux-com
# web: http://www.fgedu.net.cn
# from:www.itpux.com.qq113257174.wx:itpux-com
# web: http://www.fgedu.net.cn
# from:www.itpux.com.qq113257174.wx:itpux-com
# web: http://www.fgedu.net.cn
# 共享内存清理脚本
export ORACLE_HOME=/oracle/app/oracle/product/19c/dbhome_1
export ORACLE_SID=FGEDUDB
export PATH=$ORACLE_HOME/bin:$PATH
# 检查数据库状态
db_status=$(ps -ef | grep ora_pmon_$ORACLE_SID | grep -v grep)
if [ -z “$db_status” ]; then
echo “Database is not running, cleaning shared memory…”
# 获取Oracle用户的共享内存段
shm_segments=$(ipcs -m | grep oracle | awk ‘{print $2}’)
for seg in $shm_segments; do
echo “Removing shared memory segment: $seg”
ipcrm -m $seg
done
# 获取Oracle用户的信号量
sem_segments=$(ipcs -s | grep oracle | awk ‘{print $2}’)
for seg in $sem_segments; do
echo “Removing semaphore segment: $seg”
ipcrm -s $seg
done
echo “Shared memory cleanup completed at $(date)” >> /home/oracle/scripts/shared_memory_cleanup.log
else
echo “Database is running, skipping cleanup”
fi
# 2. 设置脚本权限
$ chmod +x /home/oracle/scripts/clean_shared_memory.sh
# 3. 测试脚本
$ /home/oracle/scripts/clean_shared_memory.sh
Database is not running, cleaning shared memory…
Removing shared memory segment: 1234567890
Removing shared memory segment: 1234567891
Removing semaphore segment: 9876543210
Removing semaphore segment: 9876543211
Shared memory cleanup completed at Mon Mar 31 10:00:00 CST 2026
# 4. 验证清理结果
$ ipcs -m | grep oracle
# 5. 启动数据库
$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 – Production on Mon Mar 31 10:00:00 2026
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 5368709120 bytes
Fixed Size 9142560 bytes
Variable Size 1090519040 bytes
Database Buffers 4261412864 bytes
Redo Buffers 7634944 bytes
Database mounted.
Database opened.
# 6. 验证共享内存
$ ipcs -m | grep oracle
0x00000000 1234567892 oracle 600 5368709120 50
0x00000000 1234567893 oracle 600 5368709120 50
3.2 ORA-27101错误监控
3.2.1 配置ORA-27101错误监控脚本
$ vi /home/oracle/scripts/monitor_ora27101.sh
#!/bin/bash
# from:www.itpux.com.qq113257174.wx:itpux-com
# web: http://www.fgedu.net.cn
# from:www.itpux.com.qq113257174.wx:itpux-com
# web: http://www.fgedu.net.cn
# from:www.itpux.com.qq113257174.wx:itpux-com
# web: http://www.fgedu.net.cn
# ORA-27101错误监控脚本
export ORACLE_HOME=/oracle/app/oracle/product/19c/dbhome_1
export ORACLE_SID=FGEDUDB
export PATH=$ORACLE_HOME/bin:$PATH
# 定义变量
ERROR_LOG=”/home/oracle/scripts/ora27101_errors.log”
EMAIL=”admin@fgedu.net.cn”
# 检查ORA-27101错误
check_ora27101_errors() {
local last_check_file=”/home/oracle/scripts/last_ora27101_check.txt”
local current_time=$(date +%s)
if [ -f “$last_check_file” ]; then
local last_check=$(cat “$last_check_file”)
local time_diff=$((current_time – last_check))
if [ $time_diff -lt 3600 ]; then
echo “Last check was $time_diff seconds ago, skipping…”
return 0
fi
fi
# 检查共享内存
local shm_count=$(ipcs -m | grep oracle | wc -l)
if [ $shm_count -eq 0 ]; then
echo “Found ORA-27101 error:” >> “$ERROR_LOG”
echo “Shared memory does not exist” >> “$ERROR_LOG”
echo “Timestamp: $(date)” >> “$ERROR_LOG”
echo “” >> “$ERROR_LOG”
# 发送告警邮件
echo “ORA-27101 error detected: shared memory realm does not exist” | mail -s “ORA-27101 Alert” “$EMAIL”
# 分析共享内存状态
analyze_shared_memory
fi
# 更新最后检查时间
echo “$current_time” > “$last_check_file”
}
# 分析共享内存状态
analyze_shared_memory() {
# 检查Oracle进程
local pmon_process=$(ps -ef | grep ora_pmon_$ORACLE_SID | grep -v grep)
echo “PMON Process:” >> “$ERROR_LOG”
echo “$pmon_process” >> “$ERROR_LOG”
echo “” >> “$ERROR_LOG”
# 检查共享内存
local shared_memory=$(ipcs -m | grep oracle)
echo “Shared Memory:” >> “$ERROR_LOG”
echo “$shared_memory” >> “$ERROR_LOG”
echo “” >> “$ERROR_LOG”
# 检查内核参数
local kernel_params=$(sysctl -a | grep kernel.shm)
echo “Kernel Parameters:” >> “$ERROR_LOG”
echo “$kernel_params” >> “$ERROR_LOG”
echo “” >> “$ERROR_LOG”
}
# 主函数
main() {
check_ora27101_errors
echo “ORA-27101 error monitoring completed at $(date)” >> “$ERROR_LOG”
}
# 执行主函数
main
# 2. 设置脚本权限
$ chmod +x /home/oracle/scripts/monitor_ora27101.sh
# 3. 测试脚本
$ /home/oracle/scripts/monitor_ora27101.sh
# 4. 设置定期监控
$ crontab -e
# 每小时检查ORA-27101错误
0 * * * * /home/oracle/scripts/monitor_ora27101.sh >> /home/oracle/scripts/monitor_ora27101.log 2>&1
3.2.2 配置数据库监控
SQL> create or replace view shared_memory_monitor as
select
‘SHARED_MEMORY’ as memory_type,
(select count(*) from v$sgastat) as sga_components,
(select sum(bytes) from v$sgastat) as total_sga_bytes,
(select value from v$parameter where name = ‘sga_target’) as sga_target,
(select value from v$parameter where name = ‘sga_max_size’) as sga_max_size
from dual;
View created.
# 2. 查询共享内存状态
SQL> select * from shared_memory_monitor;
MEMORY_TYPE SGA_COMPONENTS TOTAL_SGA_BYTES SGA_TARGET SGA_MAX_SIZE
————– ————– ————— ————- ————-
SHARED_MEMORY 20 5368709120 4294967296 5368709120
# 3. 创建SGA组件监控视图
SQL> create or replace view sga_component_monitor as
select
name,
bytes,
round(bytes/1024/1024, 2) as mb,
round(bytes/1024/1024/1024, 2) as gb,
(select sum(bytes) from v$sgastat) as total_bytes,
round(bytes/(select sum(bytes) from v$sgastat)*100, 2) as pct
from v$sgastat
where name in (‘buffer_cache’, ‘shared_pool’, ‘large_pool’, ‘java_pool’, ‘streams_pool’, ‘log_buffer’)
order by bytes desc;
View created.
# 4. 查询SGA组件状态
SQL> select * from sga_component_monitor;
NAME BYTES MB GB TOTAL_BYTES PCT
—————– ———- ———- ———- ———– ———-
buffer_cache 4261412864 4064.00 3.97 5368709120 79.38
shared_pool 1073741824 1024.00 1.00 5368709120 20.00
log_buffer 7634944 7.28 0.01 5368709120 0.14
large_pool 67108864 64.00 0.06 5368709120 1.25
java_pool 67108864 64.00 0.06 5368709120 1.25
streams_pool 0 0.00 0.00 5368709120 0.00
# 5. 创建ORA-27101错误告警
SQL> create or replace procedure ora27101_error_alert as
v_sga_target number;
v_sga_max_size number;
v_total_sga number;
v_email varchar2(100) := ‘admin@fgedu.net.cn’;
begin
— 获取SGA参数
select value into v_sga_target from v$parameter where name = ‘sga_target’;
select value into v_sga_max_size from v$parameter where name = ‘sga_max_size’;
select sum(bytes) into v_total_sga from v$sgastat;
if v_total_sga = 0 then
— 发送告警
dbms_output.put_line(‘SGA Target: ‘ || v_sga_target);
dbms_output.put_line(‘SGA Max Size: ‘ || v_sga_max_size);
dbms_output.put_line(‘Total SGA: ‘ || v_total_sga);
dbms_output.put_line(‘Recommendation: Check shared memory or start database’);
else
dbms_output.put_line(‘SGA Target: ‘ || v_sga_target);
dbms_output.put_line(‘SGA Max Size: ‘ || v_sga_max_size);
dbms_output.put_line(‘Total SGA: ‘ || v_total_sga);
dbms_output.put_line(‘Shared memory is normal’);
end if;
end ora27101_error_alert;
/
Procedure created.
# 6. 执行告警存储过程
SQL> set serveroutput on
SQL> exec ora27101_error_alert;
SGA Target: 4294967296
SGA Max Size: 5368709120
Total SGA: 5368709120
Shared memory is normal
PL/SQL procedure successfully completed.
# 7. 创建定时任务
SQL> begin
dbms_scheduler.create_job(
job_name => ‘ORA27101_ERROR_ALERT_JOB’,
job_type => ‘STORED_PROCEDURE’,
job_action => ‘ORA27101_ERROR_ALERT’,
start_date => systimestamp,
repeat_interval => ‘FREQ=HOURLY;INTERVAL=1’,
enabled => true
);
end;
/
PL/SQL procedure successfully completed.
3.3 ORA-27101错误故障处理
3.3.1 ORA-27101错误处理
$ sqlplus scott/tiger@FGEDUDB
SQL*Plus: Release 19.0.0.0.0 – Production on Mon Mar 31 10:00:00 2026
Copyright (c) 1982, 2020, Oracle. All rights reserved.
ERROR:
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3640
Additional information: 3641
# 分析步骤
# 1. 查看共享内存状态
$ ipcs -m | grep oracle
# 2. 查看Oracle进程
$ ps -ef | grep ora_pmon
# 3. 查看Oracle环境变量
$ echo $ORACLE_SID
$ echo $ORACLE_HOME
# 4. 查看内核参数
$ sysctl -a | grep kernel.shm
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
# 5. 分析错误原因
# 错误代码：ORA-27101
# 错误信息：shared memory realm does not exist
# 共享内存状态：不存在
# 错误原因：数据库实例未启动或共享内存已被删除
# 6. 解决方案：启动数据库实例
$ export ORACLE_SID=FGEDUDB
$ export ORACLE_HOME=/oracle/app/oracle/product/19c/dbhome_1
$ export PATH=$ORACLE_HOME/bin:$PATH
$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 – Production on Mon Mar 31 10:00:00 2026
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 5368709120 bytes
Fixed Size 9142560 bytes
Variable Size 1090519040 bytes
Database Buffers 4261412864 bytes
Redo Buffers 7634944 bytes
Database mounted.
Database opened.
# 7. 验证问题解决
$ sqlplus scott/tiger@FGEDUDB
SQL*Plus: Release 19.0.0.0.0 – Production on Mon Mar 31 10:00:00 2026
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 – Production
Version 19.3.0.0.0
SQL> select instance_name, status, database_status, startup_time
from v$instance;
INSTANCE_NAME STATUS DATABASE_STATUS STARTUP_TIME
—————- ———— —————– ——————-
FGEDUDB OPEN ACTIVE 31-MAR-26 10:00:00
# 8. 验证共享内存
$ ipcs -m | grep oracle
0x00000000 1234567892 oracle 600 5368709120 50
0x00000000 1234567893 oracle 600 5368709120 50
# 9. 预防措施
# – 配置数据库自动启动
# – 定期检查共享内存状态
# – 配置共享内存监控
# – 定期测试连接
3.3.2 内核参数错误处理
$ sysctl -a | grep kernel.shm
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
# 2. 计算所需内核参数
# SGA大小：5GB = 5 * 1024 * 1024 * 1024 = 5368709120 bytes
# shmmax应大于SGA大小
# shmall应大于SGA大小/页面大小
# 页面大小
$ getconf PAGE_SIZE
4096
# 计算shmall
# shmall = SGA大小 / PAGE_SIZE = 5368709120 / 4096 = 1310720
# 3. 修改内核参数
$ vi /etc/sysctl.conf
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
fs.file-max = 6815744
net.ipv4.ip_local_port_range = 9000 65500
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576
# 4. 使内核参数生效
$ sysctl -p
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
fs.file-max = 6815744
net.ipv4.ip_local_port_range = 9000 65500
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576
# 5. 验证内核参数
$ sysctl -a | grep kernel.shm
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
# 6. 启动数据库
$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 – Production on Mon Mar 31 10:00:00 2026
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 5368709120 bytes
Fixed Size 9142560 bytes
Variable Size 1090519040 bytes
Database Buffers 4261412864 bytes
Redo Buffers 7634944 bytes
Database mounted.
Database opened.
# 7. 验证数据库状态
SQL> select instance_name, status, database_status, startup_time
from v$instance;
INSTANCE_NAME STATUS DATABASE_STATUS STARTUP_TIME
—————- ———— —————– ——————-
FGEDUDB OPEN ACTIVE 31-MAR-26 10:00:00
Part04-生产案例与实战讲解
4.1 ORA-27101错误分析案例
在生产环境中分析ORA-27101错误的完整案例：
4.1.1 场景描述
某企业生产数据库出现ORA-27101共享内存不存在错误，需要分析错误原因并解决问题。
4.1.2 分析步骤
$ sqlplus scott/tiger@FGEDUDB
SQL*Plus: Release 19.0.0.0.0 – Production on Mon Mar 31 10:00:00 2026
Copyright (c) 1982, 2020, Oracle. All rights reserved.
ERROR:
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3640
Additional information: 3641
# 2. 查看共享内存状态
$ ipcs -m | grep oracle
# 3. 查看Oracle进程
$ ps -ef | grep ora_pmon
# 4. 查看内核参数
$ sysctl -a | grep kernel.shm
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
# 5. 分析错误原因
# 错误代码：ORA-27101
# 错误信息：shared memory realm does not exist
# 共享内存状态：不存在
# 错误原因：数据库实例未启动或共享内存已被删除
# 6. 解决方案：启动数据库实例
$ export ORACLE_SID=FGEDUDB
$ export ORACLE_HOME=/oracle/app/oracle/product/19c/dbhome_1
$ export PATH=$ORACLE_HOME/bin:$PATH
$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 – Production on Mon Mar 31 10:00:00 2026
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 5368709120 bytes
Fixed Size 9142560 bytes
Variable Size 1090519040 bytes
Database Buffers 4261412864 bytes
Redo Buffers 7634944 bytes
Database mounted.
Database opened.
# 7. 验证问题解决
$ sqlplus scott/tiger@FGEDUDB
SQL*Plus: Release 19.0.0.0.0 – Production on Mon Mar 31 10:00:00 2026
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 – Production
Version 19.3.0.0.0
SQL> select instance_name, status, database_status, startup_time
from v$instance;
INSTANCE_NAME STATUS DATABASE_STATUS STARTUP_TIME
—————- ———— —————– ——————-
FGEDUDB OPEN ACTIVE 31-MAR-26 10:00:00
4.2 ORA-27101错误故障处理
在ORA-27101错误故障处理过程中的方法和技巧：
4.2.1 故障处理流程
# 1. 错误识别
# – 监控共享内存状态
# – 检查错误信息
# – 确认错误参数
# 2. 错误分析
# – 查看共享内存状态
# – 检查Oracle进程
# – 分析内核参数
# 3. 错误处理
# – 启动数据库实例
# – 修正内核参数
# – 清理残留共享内存
# 4. 错误预防
# – 配置数据库自动启动
# – 定期检查共享内存状态
# – 制定预防措施
# 示例：ORA-27101错误处理
# 1. 错误识别
$ sqlplus scott/tiger@FGEDUDB
SQL*Plus: Release 19.0.0.0.0 – Production on Mon Mar 31 10:00:00 2026
Copyright (c) 1982, 2020, Oracle. All rights reserved.
ERROR:
ORA-27101: shared memory realm does not exist
# 2. 错误分析
$ ipcs -m | grep oracle
$ ps -ef | grep ora_pmon
$ sysctl -a | grep kernel.shm
# 3. 错误处理
$ export ORACLE_SID=FGEDUDB
$ export ORACLE_HOME=/oracle/app/oracle/product/19c/dbhome_1
$ export PATH=$ORACLE_HOME/bin:$PATH
$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 – Production on Mon Mar 31 10:00:00 2026
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 5368709120 bytes
Fixed Size 9142560 bytes
Variable Size 1090519040 bytes
Database Buffers 4261412864 bytes
Redo Buffers 7634944 bytes
Database mounted.
Database opened.
# 4. 验证处理结果
SQL> select instance_name, status, database_status, startup_time
from v$instance;
INSTANCE_NAME STATUS DATABASE_STATUS STARTUP_TIME
—————- ———— —————– ——————-
FGEDUDB OPEN ACTIVE 31-MAR-26 10:00:00
# 5. 错误预防
# – 配置数据库自动启动
# – 定期检查共享内存状态
# – 配置共享内存监控
# – 定期测试连接
4.3 ORA-27101错误优化
优化ORA-27101错误处理配置的最佳实践：
4.3.1 优化共享内存管理
SQL> create or replace procedure optimize_shared_memory as
v_sga_target number;
v_sga_max_size number;
v_total_sga number;
v_buffer_cache number;
v_shared_pool number;
begin
— 获取SGA参数
select value into v_sga_target from v$parameter where name = ‘sga_target’;
select value into v_sga_max_size from v$parameter where name = ‘sga_max_size’;
select sum(bytes) into v_total_sga from v$sgastat;
select sum(bytes) into v_buffer_cache from v$sgastat where name = ‘buffer_cache’;
select sum(bytes) into v_shared_pool from v$sgastat where name = ‘shared_pool’;
— 如果共享内存不存在，建议启动数据库
if v_total_sga = 0 then
dbms_output.put_line(‘SGA Target: ‘ || v_sga_target);
dbms_output.put_line(‘SGA Max Size: ‘ || v_sga_max_size);
dbms_output.put_line(‘Total SGA: ‘ || v_total_sga);
dbms_output.put_line(‘Recommendation: Start database or check shared memory’);
else
dbms_output.put_line(‘SGA Target: ‘ || round(v_sga_target/1024/1024/1024, 2) || ‘ GB’);
dbms_output.put_line(‘SGA Max Size: ‘ || round(v_sga_max_size/1024/1024/1024, 2) || ‘ GB’);
dbms_output.put_line(‘Total SGA: ‘ || round(v_total_sga/1024/1024/1024, 2) || ‘ GB’);
dbms_output.put_line(‘Buffer Cache: ‘ || round(v_buffer_cache/1024/1024/1024, 2) || ‘ GB’);
dbms_output.put_line(‘Shared Pool: ‘ || round(v_shared_pool/1024/1024/1024, 2) || ‘ GB’);
dbms_output.put_line(‘Shared memory is normal’);
end if;
end optimize_shared_memory;
/
Procedure created.
# 2. 执行优化存储过程
SQL> set serveroutput on
SQL> exec optimize_shared_memory;
SGA Target: 4 GB
SGA Max Size: 5 GB
Total SGA: 5 GB
Buffer Cache: 3.97 GB
Shared Pool: 1 GB
Shared memory is normal
PL/SQL procedure successfully completed.
# 3. 创建定时任务
SQL> begin
dbms_scheduler.create_job(
job_name => ‘OPTIMIZE_SHARED_MEMORY_JOB’,
job_type => ‘STORED_PROCEDURE’,
job_action => ‘OPTIMIZE_SHARED_MEMORY’,
start_date => systimestamp,
repeat_interval => ‘FREQ=DAILY;INTERVAL=1’,
enabled => true
);
end;
/
PL/SQL procedure successfully completed.
# 4. 配置内核参数优化
$ vi /etc/sysctl.conf
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
fs.file-max = 6815744
net.ipv4.ip_local_port_range = 9000 65500
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576
# 5. 使内核参数生效
$ sysctl -p
# 6. 验证内核参数
$ sysctl -a | grep kernel.shm
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
Part05-风哥经验总结与分享
5.1 ORA-27101错误总结
Oracle ORA-27101错误是共享内存不存在错误，具有以下特点：
- 共享内存不存在：共享内存区域不存在
- 实例未启动：数据库实例未启动
- 内存段被删除：共享内存段已被删除
- 权限问题：共享内存权限问题
- 系统资源不足：系统内存资源不足
5.2 ORA-27101错误检查清单
Oracle ORA-27101错误检查清单：
- 错误识别：识别错误信息和参数
- 错误分析：分析共享内存状态
- 错误处理：处理错误问题
- 错误验证：验证处理结果
- 错误预防：制定预防措施
- 错误记录：记录处理过程
5.3 ORA-27101错误工具推荐
Oracle ORA-27101错误工具推荐：
- SQL*Plus：命令行工具
- SQL Developer：图形化工具
- Enterprise Manager：企业级管理工具
- ipcs：共享内存查看工具
- ipcrm：共享内存删除工具
- sysctl：内核参数配置工具
本文由风哥教程整理发布,仅用于学习测试使用,转载注明出处:http://www.fgedu.net.cn/10327.html
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