Real-World Performance - 13 - Large Dynamic Connection Pools - Part 1
Why Stack Overflow recommends it
Stack Overflow users link it when explaining how many database connections a pool should open, since it shows performance falling as connections far exceed CPU capacity.
Recommended by 3 people across 3 different months, 2017 to 2023.
What it is
Part 1 of Oracle's Real-World Performance series on large dynamic connection pools. Andrew Holdsworth of Oracle's Real-World Performance group demonstrates how oversized connection pools hurt database throughput and response time.
What people said
Recommends BobC · 2017-02 · Stack Overflow · on “Oracle: determine maximum number of connections suppported”
This is a very good question. In general as a rule of thumb, we recommend the number of connections to Oracle be somewhere between 1x and 10x the number of CPU cores. Have a look at this video put together by the Oracle Real-World Performance team on this subject: [this video]
Recommends Douglas Surber · 2019-04 · Stack Overflow · on “How to size connection pool against Oracle Autonomous Database (ATP)?”
The link [LINK] David Fdez provided above is correct. As a rule of thumb for maximum performance the maximum number of connections to an Oracle database should be a small number times the number of hardware threads the server has. This is the total across all clients. See [this video] . This is not always practical. If there are hundreds of clients connecting to a small server, even at one connection per client that limit is exceeded. That's ok. The database will still work just fine but it will not achieve the maximum performance it is capable of; it will be spending more time context switching than is ideal. The rule of thumb is still useful. It tells us that each client should only have one co
Recommends Ashwin Prabhu · 2023-01 · Stack Overflow · on “What are the downside of having more db connections open than required?”
It is tough to answer without looking at the numbers. But since you are posing a generic question, the generic answer is yes it would but YMMV. I find this video [this video] recording by Andrew about Oracle DB connection pool performance a good reference point to understand how the DB performance curve is related to open connections. The video is old but it sets the first principles that you can take away to refine your thinking further.
Critical Andrey B. Panfilov · 2021-12 · Stack Overflow · on “Dynamic resizing connection pool size - Apache Tomcat JDBC Connection Pool”
That is hardly possible that increasing pool size may improve performance or throughput, check this video for example: [this video]