Why pulsar retention quota must exceed configured backlog quota

[mnit016]

Hello everyone,

I'm new to Pulsar, recently I get into a problem when configure the backlog/retention quota for namespace.

The problem:
retention: {time: -1, size: 10M} => then I can set backlog quota as much as I want.
But if retention: {time: 1, size: 10M} => when I set backlog quota exceed 10M, it said "Backlog Quota exceeds configured Retention quota for namespace. Please increase retention quota and retry", I have no idea why.

Could someone please help to explain for me?
Thanks

[Jason918]

retention: {time: -1, size: 10M} => then I can set backlog quota as much as I want.

This seems to be a bug. It's introduced in #10401 since v2.8.0

[michaeljmarshall]

@mnit016 - are you willing to create a GitHub issue for this bug? Thanks!

[michaeljmarshall]

I just discovered the "create issue from discussion" button. I created an issue for this discussion.

[Jason918]

I have pushed a fix #17706

[mnit016]

Hello @Jason918 , @michaeljmarshall , but I still confused, could you please explain for me why backlog quota couldn't exceed the retention? Is there any risk if we set backlog quota larger than retention?

[Jason918]

Hello @Jason918 , @michaeljmarshall , but I still confused, could you please explain for me why backlog quota couldn't exceed the retention? Is there any risk if we set backlog quota larger than retention?

Messages will be deleted if they meet the constrains of retention policy. So if backlog quota is larger than retention, it just won't take effect.