In this video, explore the Oracle database architecture and focus on the Oracle instance and its functions for caching data and processing user transactions.
- [Instructor] Behold, the magnificent Oracle database architecture, a multitude of individual components working in tandem to allow an Oracle database to be, well, a database, allowing you to read and write data from tables in a way that's safe, speedy, scalable, and secure. The Oracle database architecture can be divided into three major components. Let's start by taking a bird's eye's view of the Oracle architecture and list the three major components making up our Oracle database.
Our first component is the Oracle instance. Our second component is the Oracle database storage. And our third component are the Oracle server processes, or SPs. Let's start by talking a little more about the Oracle instance, which is basically the Oracle program, or binary, loaded into the server RAM. It exists only in memory, and created by Oracle every time you start up your database. Created, you say? Yep, it's non-persistent and disappears each time the database re-starts.
What does it do? Well, it contains special areas used to cache really important data as well as metadata into memory. Quick side note, what's metadata, you ask? Well, that's data which describes other data. For example, we can have an employees table storing employees rows, that's our actual data. The structure of the table and its column is also known as metadata. Okay, back to the topic of the Oracle instance.
We talked about the Oracle instance caching frequently accessed data and metadata into memory. So why do we need to cache data in memory in the first place? Because reading from memory is a lot faster compared to reading from disk. It makes sense to store frequently accessed data in memory so that after the first database session read the data from disk, which will be slow, it will be cached so that subsequent sessions requesting the same data or metadata will get a nice boost to read performance.
But hold on, caching data and metadata in memory is not all the Oracle instance does. It also includes a set of processes running in the background which are called, you guessed it, background processes. These background processes work in tandem with the Oracle instance in memory caches we just described to perform various routine database operations. These operations include writing data to disk, ensuring database consistency, and more. You know, basically everything the Oracle database has to do on a regular basis to ensure it's consistent, well-tuned, operational, and secure.
Okay, so that was the Oracle database instance. But the Oracle instance alone isn't yet a fully functional database. Remember that I mentioned the non-persistent nature of the Oracle instance, the fact that it gets re-created in memory after every Oracle database re-starts? Hmm, that would mean that the data cached in the Oracle instance will get vaporized each time we re-start our database. We will lose it, what gives? We want our data in our database to be safe and secure.
Hmm, perhaps on disk somewhere?
After completing this course, you'll have fundamentals required for installation, configuration, and administration of an Oracle 12c database.
- Database instance and storage
- Instance memory pools
- Instance background processes
- Client connections
- Database storage file types
- Control files and backup files
- Multitenant databases
- Starting and stopping the database
- Installing Oracle 12c software
- Using the developer tools
- Database management