The Slotted Counter Pattern
The Slotted Counter Pattern
It is a common database pattern to increment an INT column when an event happens, such as a download or page view. You can go far with this pattern until bursts of these types of events happen in parallel and you experience contention on a single row. When multiple transactions are trying to update the counter, you are essentially forcing these transactions to run serially, which is bad for concurrency and can cause deadlocks. You can also see dramatic increases in query time when bursts like this occur.
Note
a lot of simple things break when the needs of scale and real time start putting on pressure.
Published
2024
Summary
It is a common database pattern to increment an INT column when an event happens, such as a download or page view. You can go far with this pattern until bursts of these types of events happen in parallel and you experience contention on a single row. When multiple transactions are trying to update the counter, you are essentially forcing these transactions to run serially, which is bad for concurrency and can cause deadlocks. You can also see dramatic increases in query time when bursts like this occur.
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