fix(storage): fix ConcurrentQueue condvar race and spurious wakeups

[Boat2U]

Title

Type

• feat: (new feature)
• fix: (bug fix)
• docs: (doc update)
• refactor: (refactor code)
• test: (test code)
• chore: (other updates)

Scope

• query: (query engine)
  • parser: (frontend parser)
  • planner: (frontend planner)
  • optimizer: (query optimizer)
  • executor: (execution engine)
  • op: (operators)
• storage: (storage engine)
  • mvcc: (multi version concurrency control)
  • schema: (graph model and topology)
• tool: (tools)
  • cli: (cli)
  • sdk: (sdk)
• none: (N/A)

Description

Issue: #131

Checklist

• I have prepared the pull request title according to the requirements.
• I have successfully run all unit tests and integration tests.
• I have already rebased the latest master branch.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.

[Copilot]

Pull request overview

This PR fixes a critical race condition and spurious wakeup issues in the ConcurrentQueue implementation. The fix removes a separate condition variable mutex that created a race condition where push notifications could be lost, and replaces the wait mechanism with a predicate-based approach that guards against spurious wakeups.

Key Changes

• Removed the redundant c: Mutex<bool> field that was causing a race condition
• Changed wait_for_push_notify to use wait_timeout_while with a predicate instead of wait_timeout, ensuring the wait condition is checked atomically with the same mutex that protects the queue state
• Added a clarifying comment explaining the spurious wakeup protection

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[liuys-dase]

LGTM