应用报连接异常时：
1、数据库是否可以正常连接
2、数据库服务器内存核cpu使用率高不高
3、会话数是否达到上限
select count(*) from v$sessions;–查当前会话数
select para_value from v$dm_ini where para_name=‘MAX_SESSIONS’;
select para_value from v$dm_ini where para_name=‘MAX_SESSION_STATEMENT’;
4、数据库日志中是否有报错
dmdbms/log/dm_实例名_202212.log
5、用户是否有做资源限制
select
username as “用户名” ,
password as “密码” ,
conn_idle_time as “会话空闲期” ,
life_time as “口令有效期”,
lock_time as “锁定时间”,
grace_time as “口令宽限期”,
failed_num as “失败登陆次数”,
cast(c.info1 as int) as 会话持续期,
lastest_locked as “最后一次锁定时间”,
failed_attemps as “用户自上一次成功登录以来的失败登录次数”
from sysusers a,all_users b,sysresources c
where a.id=b.user_id and a.id = c.id;
6、授权是否有限制
select lic_version,case server_series when ‘P’ then ‘个人版’ when ‘S’ then ‘标注版’
when ‘E’ then ‘企业版’ when ‘A’ then ‘安全版’ when ‘T’ then ‘可信版’ when ‘X’ then ‘定制版’ else ‘其他’ end ,
case server_type when ‘1’ then ‘正式版’ when ‘2’ then ‘测试版’ when ‘3’ then ‘试用版’ else ‘其他’ end ,
expired_date 有效期,AUTHORIZED_USER_NUMBER 授权用户数,CONCURRENCY_USER_NUMBER 并发连接数,MAX_CPU_NUM cpu,
HARDWARE_ID 绑定的硬件编码,PRODUCT_TYPE 产品类型 ,HARDWARE_TYPE 硬件绑定类型,CLUSTER_TYPE 授权使用的集群类型,
TABLE_RECORD_NUMBER_LIMIT 单表最大数据行数限制,TOTAL_SPACE_LIMIT 数据总空间大小限制
from v$license;
以上如果都没问题：
1、应用中调大socket
2、抓慢sql处理下
https://www.cnblogs.com/wuran222/p/16392142.html
如果还不行，只能应用中抓包看看是不是网络的问题