Bewithgaurav/profiling

LATEST_UPDATE.md

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+# Latest Update — Profiler Branch Status
+
+**Date:** 2026-04-09  
+**Branch:** `profiler-updated`  
+**Base:** Rebased on latest `origin/main` (`9bc78ae`) — clean, no conflicts
+
+---
+
+## What's on This Branch
+
+### ✅ Phase 1: Core Profiling Infrastructure (COMPLETE)
+- **`performance_counter.hpp`** — Thread-safe RAII profiling with platform detection (Windows/Linux/macOS)
+- **`ddbc_bindings.cpp`** — Integrated profiling submodule with Python API
+- **`run_profiler.py`** — Profiler runner script
+- **`profiling_results.md`** — 1,250 lines of previous profiling data
+
+**Python API:**
+```python
+from mssql_python.pybind.ddbc_bindings import profiling
+
+profiling.enable()
+profiling.disable()
+profiling.get_stats()
+profiling.reset()
+profiling.is_enabled()
+```
+
+### ✅ Phase 2: Documentation (COMPLETE)
+| Document | Lines | Description |
+|---|---|---|
+| `PROFILER_SUMMARY.md` | 265 | Executive summary of profiling work |
+| `PERF_TIMER_LOCATIONS.md` | 415 | All 43 timer locations with code snippets |
+| `ENHANCED_PROFILING_PLAN.md` | 484 | New profiling points + benchmark definitions |
+| `PROFILER_UPGRADE_STATUS.md` | 122 | Status tracker |
+
+### 📋 Phase 3: Implementation (TODO)
+- **43 PERF_TIMER calls** documented but not yet inserted
+- Priority target: `FetchBatchData` / `construct_rows` — the critical bottleneck
+- ⚠️ Line numbers in `PERF_TIMER_LOCATIONS.md` need re-mapping after rebase (main grew significantly)
+
+---
+
+## New Commits on Main Since Original Branch Point
+
+13 commits merged into main since we originally branched (`95eef16`→`9bc78ae`):
+
+| PR | Description | Impact on Profiler |
+|---|---|---|
+| #354 | Arrow fetch support | **High** — new fetch path needs profiling points |
+| #446 | sql_variant support | Medium — new type processing to profile |
+| #463 | native_uuid support | Low — new type handler |
+| #477 | AI-powered issue triage | None |
+| #432 | Stress test pipeline | None — CI only |
+| #479 | datetime.time microseconds fix | Low |
+| #483 | Credential instance cache fix | Low |
+| #494 | Explicit exports from main module | None |
+| #488 | Bulkcopy auth field cleanup | None |
+| #466 | NULL param type mapping fix | Low |
+| #475 | Bump mssql-py-core to 0.1.1 | None |
+| #474 | Export Row class, refactor __init__.py | None |
+| #465 | qmark detection fix | None |
+
+### Key Takeaway
+`ddbc_bindings.cpp` grew from ~4,500 to **5,895 lines** (arrow fetch + sql_variant). Profiler commit rebased cleanly — no conflicts. Phase 3 timer locations need line-number refresh, and **arrow fetch** (#354) introduces a new code path that should get its own profiling points.
+
+---
+
+## Commit Stats
+- **Total changes:** +2,802 lines across 8 files
+- **Original commit:** `2caa084` → rebased to `5e15451`
+- **Reference PR:** #147 (original profiler branch)
+- **Key result:** Linux slowdown reduced from **2.3x** to **16%** vs Windows
+
+---
+
+## Next Steps
+1. Re-map 43 PERF_TIMER locations to current line numbers
+2. Add profiling points for new arrow fetch path (#354)
+3. Add profiling points for sql_variant processing (#446)
+4. Begin Phase 3 implementation (insert PERF_TIMER calls)
+5. Run benchmarks to establish new baseline post-rebase