enh(stream): reset table scan in reader

[wangmm0220]

Description

Please briefly describe the code changes in this pull request.

Checklist

Please check the items in the checklist if applicable.

• Is the user manual updated?
• Are the test cases passed and automated?
• Is there no significant decrease in test coverage?

[gemini-code-assist]

Summary of Changes

Hello @wangmm0220, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a significant enhancement to the stream processing execution engine by refining how table scan tasks are reset. The changes provide a more intelligent and generalized mechanism for managing task states, allowing the system to either fully recreate a task or perform a targeted state reset based on the operator type. This refactoring aims to improve the efficiency, correctness, and robustness of stream processing, especially in dynamic or repetitive table scan operations.

Highlights

• Refactored Stream Task Reset Logic: Introduced a new function, qNeedReset, to intelligently determine whether a stream execution task requires a full recreation or just a state-only reset, providing more granular control over task lifecycle.
• Generalized Table Scan Reset Mechanism: The qResetTableScan function has been refactored to use a polymorphic approach, now calling operator-specific resetStateFn functions for TABLE_SCAN, TABLE_MERGE_SCAN, and SYSTABLE_SCAN types, enhancing flexibility and maintainability.
• Detailed Operator State Reset Implementations: Dedicated reset functions (resetTableScanOperatorState, resetTableMergeScanOperatorState, resetSysTableScanOperState) were implemented for various scan operators, ensuring thorough state cleanup and reinitialization of internal variables like scan times, group IDs, and data readers.
• Improved Limit Information Initialization: Explicitly initialized numOfOutputRows, numOfOutputGroups, and currentGroupId fields within initLimitInfo to 0, preventing potential issues related to uninitialized values in limit and offset calculations.
• Enhanced Code Robustness: Added a NULL pointer check to the blockDataEmpty function in tdatablock.c to prevent potential crashes and improve the overall stability of data block operations.
• Test Timeout Adjustment: Increased the timeout for stream running checks in the test_snode_mgmt_replica3.py test case from 60 to 300 seconds, likely to accommodate longer processing times or more complex stream scenarios introduced by these changes.

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[gemini-code-assist]

Code Review

This pull request introduces a significant enhancement to stream processing by allowing table scan operators to be reset instead of being destroyed and recreated. This should improve performance. The changes are extensive, touching various scan operators (TableScan, TableMergeScan, SysTableScan) to add reset logic.

My review has identified a critical issue related to incorrect function signatures and pointer handling for the new qNeedReset and qResetTableScan functions, which will likely cause a crash. I have also found some minor issues, such as unused variables and leftover commented-out code that should be cleaned up.

Once the critical issue is addressed, this PR will be a great improvement.

[CLAassistant]

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