Enh/add stream latency marks

[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 significant improvements to the system's caching mechanisms, particularly for stable tag filters and statistical information. The changes aim to provide better insights into cache performance through new metrics, enhance memory safety by refining LRU cache handle management and pointer ownership, and improve debugging capabilities with more verbose logging. These updates contribute to a more robust and observable caching infrastructure.

Highlights

• Enhanced Tag Filter Cache Metrics: New fields numTagDataEntries, accTimes (now uint64_t), and hitTimes (new, uint64_t) have been added to the stable tag filter cache structures to provide more granular statistics on cache usage and efficiency.
• Improved LRU Cache Management: The getStatisInfoFromCache function now returns an LRUHandle pointer, and a new releaseCacheHandle function is introduced, ensuring proper reference counting and explicit release of LRU cache entries, preventing potential resource leaks.
• Refined Tag Condition Handling: The pTagColIds parameter in putStableCachedTableList and metaStableTagFilterCachePut has been changed to SArray**, allowing the function to take ownership of the SArray pointer and set it to NULL after use, improving memory management.
• Comprehensive Error Handling and Logging: Added explicit memory deallocation for pTagColIds and pTagCondKey in error paths, and enhanced debug/info logging with more detailed cache operation information, including tag condition strings and entry counts.

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[gemini-code-assist]

Code Review

This pull request introduces several valuable improvements, primarily focused on enhancing stream latency monitoring and fixing caching-related bugs. Key changes include adding more detailed logging and metrics for cache performance, which will significantly improve observability. A critical bug fix addresses a potential use-after-free issue by refining the management of LRU cache handles. Additionally, the code now correctly uses the stable tag filter cache's access times for metrics, fixing a notable bug. The ownership semantics for certain data structures have been clarified by using pointer-to-pointers, which helps prevent memory leaks. Overall, these are solid improvements to the stability and maintainability of the codebase. I've identified a memory leak and a couple of areas where error handling could be made more robust.

[gemini-code-assist]

The variable pTagCondStr, allocated on line 2098, is not freed in any execution path, leading to a memory leak. It should be freed in the _error cleanup block.

  taosArrayDestroy(pUidList);
  taosArrayDestroy(pTagColIds);
  taosMemFreeClear(pTagCondKey);
  taosMemFreeClear(pTagCondStr);

[gemini-code-assist]

The log message has "total tag data entries num" twice, referring to two different metrics (total in cache vs. total in the current stable table). This is confusing. The second instance should be renamed for clarity to distinguish between the total for the entire cache and the total for the current stable table.

    metaInfo("vgId:%d, suid:%" PRIu64 " new tag data filter entry added"
      "(stable num:%d, total tag data entries num:%" PRIu32 "); "
      "this tag condition data entries num:%d, "
      "current stable tag conditions num:%d, "
      "current stable total tag data entries num:%" PRIu32,
      vgId, suid, (int32_t)taosHashGetSize(pTableEntry),
      pMeta->pCache->sStableTagFilterResCache.numTagDataEntries,
      pTagConds ? (int32_t)taosHashGetSize((*pTagConds)->set) : 0,
      pFilterEntry ? (int32_t)taosHashGetSize((*pFilterEntry)->set) : 0,
      (*pTagConds)->numTagDataEntries);

[gemini-code-assist]

Returning the global terrno when taosArrayGet returns NULL is fragile. The value of terrno might be stale or not set by taosArrayGet, leading to an incorrect error code being propagated. It's more robust to return a specific error code.

      if (p1 == NULL) {
        return TSDB_CODE_INTERNAL_ERROR;
      }

[gemini-code-assist]

Similar to the previous comment, returning the global terrno is fragile. It's better to return a specific error code for robustness.

      if (p2 == NULL) {
        return TSDB_CODE_INTERNAL_ERROR;
      }