Difference between Database service and database instance

[lmundere]

Hi,

With discovery for database instances, i have realized that sometimes it injects data for example in class 'Oracle Instance', and some other times in "Oracle DB services". What is actually the difference between the two? 

[M Iftikhar]

Hi @lmundere, 

The key difference is that the Oracle Instance represents the running memory and background processes (the software) that manage the database, while the Oracle DB Services represents the logical service names that applications connect to. Discovery populates the Oracle Instance class when it finds a running instance (identified by its SID), which is a mandatory, foundational CI. It populates the Oracle DB Services class when it finds specific, named services that are often configured for load balancing or directing connections to the correct instance in a RAC (Real Application Clusters) environment. Essentially, you connect through a service to an instance.

Hope this helps!

Thanks & Regards,
Muhammad Iftikhar
If my response helped, please mark it as the accepted solution and helpful so others can benefit as well.

[Harish Bainsla]

Hi @lmundere 

* Database: A collection of physical operating system files or disk. When using Oracle 10g Automatic Storage Management (ASM) or RAW
partitions, the database may not appear as individual separate files in the operating system, but the definition remains the same.

* Instance: A set of Oracle background processes/threads and a shared memory area, which is memory that is shared across those
threads/processes running on a single computer. This the place to maintain volatile, nonpersistent stuff (some of which gets flushed to disk).
A database instance can exist without any disk storage whatsoever. It might not be the most useful thing in the world, but thinking about it
that way will definitely help draw the line between the instance and the database.

for more check below video

https://youtu.be/W5vILcBNn_8?si=79CEJ7J6VtQOkZgU

if my answer helps you mark helpful and accept solution