I recently discovered in SQL SERVER the option of not locking tables for insertion while reading some data, and thus gain some performance in some specific situations.
I searched, but I did not find anything similar in ORACLE. Does anyone know to say with propriety if it does not really exist?
Or if so, how would it be used?
According to this question in the English OS , the performance occurs when NOLOCK is used in the SELECT clause.
The answer to Oracle is: No, it does not exist.
According to the 12c documentation:
The Oracle database does not allow "dirty read", which occurs when a transaction reads data from another transaction that has not yet ended ( uncommitted ) .
Oracle automatically treats the isolation level of queries for the best performance and , while ensuring the consistency and integrity of the data.
In the link to the documentation, there is a detailed explanation on the subject:
9 Data Concurrency and Consistency
In the Oracle forum there is an old question, but something like this.
Some of the answers explain why this concept above is important to allow database (Oracle) scalability:
