用户通过DB Link对remote DB的表进行插入操作,报如下的错误:

ORA-04502: error occurred when looking up remote object

ORA-00604: error occurred at recursive SQL level 1

ORA-02020: too many database links in use

通过oerr查询oracle对02020错误的解释

[oracle@TEST ~]$ oerr ora 02020

02020, 00000, "too many database links in use"

// *Cause:  The current session has exceeded the INIT.ORA open_links maximum.

// *Action: Increase the open_links limit, or free up some open links by

//          committing or rolling back the transaction and canceling open

//          cursors that reference remote databases.

由于open_links参数达到最大值导致的错误.

查看open_links参数的设置

SQL> show parameter link

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

open_links                           integer     4

open_links_per_instance              integer     4

决定修改open_links参数,发现这个参数不能动态修改

查看数据库是否使用spfile

SQL> show parameter spfile;

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

spfile                               string      /u01/app/oracle/oracle/product

                                                 /10.2.0/db_1/dbs/spfilesfcsys.ora

先修改open_links,找个合适的时间申请停机维护,让修改生效

SQL> alter system set open_links=12 scope=spfile;

在查看open_links的设置时注意到还有另外一个参数open_links_per_instance,决定查看一官方文档弄清楚这两个参数的数据含义

open_links:一个会话最多同时打的对remote database的连接数(oracle文档原文: OPEN_LINKS specifies the maximum number of concurrent open connections to remote databases in one session.)

OPEN_LINKS_PER_INSTANCE: specifies the maximum number of migratable open

connections globally for each database instance.

更详细的内容请自己查阅Oracle® Database Reference 10g Release 2 (10.2) B14237-03文档