BoundedAsyncPool object is ready to be manipulated with even though a connection is not created yet

[little-fish]

Feature Request

Is your feature request related to a problem? Please describe

BoundedAsyncPool is ready to be manipulated with even though there is no connection available yet. This causes errors like:

java.util.concurrent.CompletionException: java.util.NoSuchElementException: Pool exhausted
	at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:331)
	at java.base/java.util.concurrent.CompletableFuture.uniApplyNow(CompletableFuture.java:670)
	at java.base/java.util.concurrent.CompletableFuture.uniApplyStage(CompletableFuture.java:658)
	at java.base/java.util.concurrent.CompletableFuture.thenApply(CompletableFuture.java:2094)
	at io.lettuce.core.support.AsyncConnectionPoolSupport$1.acquire(AsyncConnectionPoolSupport.java:121)

Describe the solution you'd like

Either wait for a connection (min-idle) to be ready upon object pool creation or provide a way to check, whether there are any available connections.

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Documentation of the BoundedAsyncPool says:

This object pool allows pre-warming with idle objects upon construction.

I would probably rephrase this sentence to make it clear that it actually requests the idle objects to be created only.

Describe alternatives you've considered

Currently I have to sleep for a fixed amount of ms to work-around this behavior. Which is pretty ugly.

Question

What is the proper way to work-around this behavior?

Thank you.

[mp911de]

Thanks for raising the issue. It's indeed an issue that creation completion cannot be awaited. I think we should introduce a new factory method (BoundedAsyncPool.create(…)) that returns a CompletableFuture so pre-warming can be properly synchronized. We also need to reflect this behavior in the documentation.

[mp911de]

That's in place now.

[He-Pin]

Thanks, I will try to update to the new version.