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This article mainly explains "how to solve database connection anomalies caused by db_domain". The content of the explanation is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "how to solve database connection anomalies caused by db_domain".

cause

A colleague was very anxious to find me, saying that the database suddenly could not log in, but the sqlplus could log in normally and reported the following error. As soon as I looked at the screenshot, I found that the error was generally caused by the database not being started. The login server found that the database was indeed open and decided to study it.

Solution process

First of all, I make sure that the database starts normally, and then check the listening status:

You can see that snooping is normal, but when I saw "kfhzbdc.yfybfwq", I suddenly realized that the database might have set db_domain, which made it impossible to access the database directly through db_name, so I checked the parameters:

Sure enough, I found that the database was set up with db_domain, so I left db_domain empty and restarted the database, and my colleagues were able to access the database directly through db_name.

Doubt

For the causes and solutions of the above problems, experienced DBA should be able to find the cause and finally solve it, but what puzzles me is that I clearly left db_domain empty and restarted the database. Theoretically, the global_name of the database should be "KFHZBDC" instead of "KFHZBDC.YFYBFWQ", but when I queried it, I found that it was still "KFHZBDC.YFYBFWQ", but at this time the database could be accessed directly through db_name. This makes me very confused, it seems that it violates the usual theoretical common sense.

It was not until I saw teacher Yang Tingkun's blog that I did not solve the problem of oracle, that is, once db_domain is set up, it cannot be removed, so how to remove db_domain, that is, to modify the data dictionary directly, but this is not recommended:

SQL > CONN / AS SYSDBA is connected.

SQL > UPDATE SYS.PROPS$ SET VALUE$ = 'KFHZBDC' WHERE NAME =' GLOBAL_DB_NAME'

Thank you for your reading, the above is the content of "how to solve database connection anomalies caused by db_domain". After the study of this article, I believe you have a deeper understanding of how to solve this problem caused by db_domain database connection anomalies, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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