Introduction to X$ Views

The SQL-less SGA access has two prerequisites: knowledge of C programming language and X$ views. Here, we will help you to better understand X$ memory structures, but C programming is beyond the scope of this book.

X$ data structures are the heart of the Oracle RDBMS kernel. They are rapidly changing memory structures in the RDBMS kernel, and they keep track of various statistics throughout the life of the instance. So if your instance has been running for several months, there is a chance that some statistic values grew too large and wrapped around. Those suspicious values can generally be ignored. The contents of X$ views always reside in memory and cannot be exported to any other database because they have no information ...

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