[igorbernstein2]

Summary

When session_load == 0 across all scopes, ClientConfigurationManager.normalizeConfig clears session_configuration, resulting in an empty SessionPoolConfiguration.getDefaultInstance().

This change updates PoolSizer and SessionPoolImpl to handle an empty SessionPoolConfiguration cleanly:

• PoolSizer:
  • Guards pendingVRpcsPerSession > 0 in getScaleDelta() to prevent divide-by-zero (+Infinity -> Integer.MAX_VALUE and int overflow when inUseCount >= 1).
  • Updates handleGoAway and handleSessionClose from getScaleDelta() >= 0 to getScaleDelta() > 0 (since onSessionClosing / onSessionClosed already decrements expectedCapacity prior to consulting PoolSizer).
• SessionPoolImpl & SessionList:
  • Guards maybeScheduleCreateSessionRetry() with budget.getMaxConcurrentRequest() <= 0 so it does not spin on a 1ms retry timer when budget == 0.
  • Makes SessionHandle.onSessionClosing() idempotent with respect to expectedCapacity.
  • In the config listener, when newConfig is SessionPoolConfiguration.getDefaultInstance(), cancels retryCreateSessionFuture and gracefully closes all sessions (CLOSE_SESSION_REASON_DOWNSIZE); when newConfig is non-empty and poolState == PoolState.STARTED, scales back up via the pre-start loop.

[gemini-code-assist]

Code Review

This pull request adds robust handling for empty or disabled session pool configurations in the Google Cloud Bigtable client. Key changes include preventing division-by-zero errors in PoolSizer when pendingVRpcsPerSession is zero, updating SessionPoolImpl to properly cancel retry futures and close active sessions when the configuration is reset to default, and adding corresponding unit tests. The review feedback correctly identifies a compilation error in SessionPoolImpl.java where Future.cancel() is called without its required boolean argument, and suggests using cancel(false) instead.

[mutianf]

do we need to set this to false after incrementing readyCount?

[igorbernstein2]

no, that field name is misleading. I renamed it to closing

[mutianf]

same question here

[igorbernstein2]

same :)

[mutianf]

would it be better to set a sessionDisabled flag? instead of checking specific params?

[igorbernstein2]

good idea, centralized the logic

[mutianf]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces support for dynamically disabling the session pool configuration, gracefully handling transitions to an empty or disabled state by closing active sessions, cancelling pending RPCs, and rejecting new calls. It also addresses potential race conditions during session startup and closing by replacing the inExpectedCount flag with a closing state, and fixes potential division-by-zero errors in the pool sizer. However, there are critical compilation errors in SessionPoolImpl.java where cancel() is called without the required boolean argument on Future objects (retryCreateSessionFuture and deadlineMonitor). These must be updated to cancel(false) to resolve the build failures.

[gemini-code-assist]

Calling cancel() with no arguments on retryCreateSessionFuture (which is a ScheduledFuture or Future) will cause a compilation error in Java. The Future.cancel method requires a boolean parameter indicating whether to interrupt the running thread. Please use cancel(false) instead.

Suggested change

	retryCreateSessionFuture.cancel();
	retryCreateSessionFuture.cancel(false);

[gemini-code-assist]

Calling cancel() with no arguments on deadlineMonitor (which is a ScheduledFuture or Future) will cause a compilation error in Java. The Future.cancel method requires a boolean parameter. Please use cancel(false) instead.

Suggested change

	deadlineMonitor.cancel();
	deadlineMonitor.cancel(false);

[gemini-code-assist]

Calling cancel() with no arguments on deadlineMonitor (which is a ScheduledFuture or Future) will cause a compilation error in Java. The Future.cancel method requires a boolean parameter. Please use cancel(false) instead.

Suggested change

	deadlineMonitor.cancel();
	deadlineMonitor.cancel(false);