Oracle Database 11g Assignment Example | Topics and Well Written Essays - 4000 words

Oracle Database 11g - Assignment Example In case there are numerous databases that exists on the very same server, then there is a distinct and separate database instance for every database. It is not possible or recommendable to share a database instance. Connection in a database instance is the communication that occurs between the instance and the user process. Session in a database instance, on the other hand, is the specific connection of a database user to an instance through the database user process that it stands for in the current user login to the instance. Whenever an Oracle Database user runs the process for the first time, it calls for a specific piece of data. The Oracle searches for the data from the database buffer cache. The search process can either find the data or not find it. If the data is found, it is referred to as a cache hit, and when it misses the data it is called a cache miss. When it is a cache hit, the data is read from the memory directly. If it is a cache miss, the data must be copied from a data file on the disk then into a buffer in the cache before the data is accessed freshly. To accommodate several users and to maximize performance, an Oracle Database multi-process system uses some extra Oracle Database process named background processes. There are numerous background processes in an Oracle Database instance. The Database Writer Process, abbreviated as DBWn, writes the buffer contents to the data files. The DBWn are tasked with writing the modified buffers in the database buffer to the system disk. Even through a single database is sufficient for most systems (DBW0), additional processes can be configured to enhance write performance if the system heavily modifies the data ((DBW1, DBW9, DBWa and through to DBWz). The control files constitute the database data (physical database information). The files are very important to the database, without them, the data files cannot be opened. The information can also contain the