Avoid metrics persistence setup for in-memory event buffering

[mj006648]

Summary

Fixes #4594.

This avoids creating MetricsPersistence for InMemoryBufferEventListener. The listener only needs to write buffered event entities, so it now passes a no-op MetricsPersistence into PolarisCallContext instead of asking the MetaStoreManagerFactory to create one.

The focused buffer-size test now verifies that flushing events does not request metrics persistence.

Tests

• ./gradlew :polaris-runtime-service:test --tests "org.apache.polaris.service.events.listeners.inmemory.InMemoryBufferEventListenerBufferSizeTest"
• ./gradlew format
• ./gradlew compileAll
• Fork CI: https://github.com/mj006648/polaris/actions/runs/28075950818

Checklist

• Don't disclose security issues! (contact security@apache.org)
• Clearly explained why the changes are needed, or linked related issues: Fixes Do not instantiate MetricsPersistence for InMemoryBufferEventListener #4594
• Added/updated tests with good coverage, or manually tested
• Added comments for complex logic, if needed
• Updated CHANGELOG.md, if needed
• Updated documentation in site/content/in-dev/unreleased, if needed

[dimas-b]

Thanks for the fix, @mj006648 ! LGTM 👍

[dimas-b]

Planning to merge on Jun 26

[flyingImer]

hmmm, I feel the right fix should be undo the metric persistence being part of the polaris call context param. But not sure if that's gonna affecting Anand's ongoing work

If we want a quick fix, wonder if the arg takes null value? I'm inclined this approach as it does not introduce the MetricsPersistence class dependency, which its class path will be changed for sure.

[dimas-b]

AFAIK, the impact on @obelix74 's work is going to be minimal (bearable).

@obelix74 : Please comment if you have a concern.

[flyrain]

I think this is a side effect of separating metricsPersistence, which forces PolarisCallContext to carry more xxxPersistence that is not needed. I don't like that direction, but since we are here. I'd create a new PolarisCallContext constructor to avoid something like NO_OP_METRICS_PERSISTENCE. If u look at the class, we actually have that constructor. Maybe we just need to remove the depreaction annotation.

[mj006648]

Thanks @flyrain and @flyingImer for the pointers.

I updated this to remove the MetricsPersistence dependency from InMemoryBufferEventListener. The listener now just passes the BasePersistence it already needs, and the fallback stays inside PolarisCallContext through the convenience constructor.

CI is green now.

[flyrain]

+1 Thanks @mj006648 for the change.

[dimas-b]

@mj006648 : sorry to cause conflicts here... Could you rebase, please?

[mj006648]

Rebased on main to resolve the conflict.

[flyrain]

Looks like the latest commit removed the changes needed, @mj006648, can you double check?

[mj006648]

Thanks for checking, @flyrain.

The code path this PR was changing appears to have been updated on main by #4866, which is why the rebase conflicted. After rebasing, this PR only keeps the regression coverage that InMemoryBufferEventListener does not create MetricsPersistence.

If you prefer not to keep this PR with only the regression coverage, I can close it.

[dimas-b]

The test change looks small, but it makes sense for the purpose of closing #4594, I think.

[dimas-b]

Merging now. If there are objections, we can revert :)

[dimas-b]

Thanks again for your contribution, @mj006648 !