Session 17 final progress: completed Tasks apache#32 and apache#33 - Float and String support (apache#82)

Author: cbb330

claude-progress.txt

@@ -3,7 +3,7 @@ ORC PREDICATE PUSHDOWN - SESSION 17 PROGRESS
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 Date: Current Session
-Completed Tasks: #32 (1 task - P2 Float Support COMPLETE!)
+Completed Tasks: #32, #33 (2 tasks - P2 Float + String Support COMPLETE!)
 
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 MAJOR ACHIEVEMENTS THIS SESSION
@@ -49,15 +49,58 @@ MAJOR ACHIEVEMENTS THIS SESSION
    - Code follows Arrow style and patterns
    - Matches allium spec "FLOATING-POINT EDGE CASES" section
 
+2. **Implemented String/Binary Predicate Pushdown Support (Task #33 - P2, PR #80, #81)**
+   - Extended ORC adapter to handle STRING, VARCHAR, CHAR, and BINARY statistics
+   - Added truncation-aware documentation and handling
+   - Created 5 comprehensive test cases covering string/binary scenarios
+
+   **Adapter Changes (adapter.cc):**
+   - Added case handlers for liborc::STRING, VARCHAR, CHAR
+   - Extract min/max from StringColumnStatistics
+   - Returns StringScalar for Arrow integration
+   - Added case handler for liborc::BINARY
+   - Extract min/max from BinaryColumnStatistics
+   - Returns BinaryScalar with Buffer::FromString
+   - Truncation notes: ORC may truncate for space efficiency
+
+   **Predicate Evaluation (file_orc.cc):**
+   - Added string/binary truncation documentation (15+ lines)
+   - Conservative approach: treats all string stats as potentially truncated
+   - Min truncation: prefix of actual minimum (lower bound)
+   - Max truncation: incremented prefix (upper bound)
+   - Current limitation: liborc doesn't expose truncation flags
+   - Future: expose flags when liborc API supports it
+
+   **Tests (file_orc_test.cc):**
+   - Added StringPredicatePushdown test (164 lines)
+   - Test 1: String basic filtering (range-based stripe skipping)
+   - Test 2: String equality (conservative with truncation)
+   - Test 3: String range filtering (compound predicates)
+   - Test 4: Empty string handling
+   - Test 5: Binary data filtering
+
+   **Code Stats:**
+   - 3 files modified: adapter.cc, file_orc.cc, file_orc_test.cc
+   - 230 lines added, 1 line deleted
+   - 41 lines in adapter (STRING/BINARY cases)
+   - 26 lines in predicate evaluation (truncation awareness)
+   - 164 lines of tests (5 comprehensive test scenarios)
+
+   **Build Verification:**
+   - arrow_orc target builds successfully
+   - Code follows Arrow style and patterns
+   - Matches allium spec "TRUNCATION HANDLING" section
+
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-COMPLETED TASKS (35 of 38 total - 92% complete!)
+COMPLETED TASKS (36 of 38 total - 95% complete!)
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 All P0 tasks complete (19 of 19 - 100%). ALL P1 tasks complete (12 of 12 - 100%).
-P2 tasks: 3 of 6 complete (50%). P3 tasks: 1 of 1 complete (100%!).
+P2 tasks: 4 of 6 complete (67%). P3 tasks: 1 of 1 complete (100%!).
 
 ✓ All previous tasks from Sessions 1-16
 ✓ Task #32: Float32/float64 type support (PR #76, #77) ← NEW THIS SESSION
+✓ Task #33: String/binary type support (PR #80, #81) ← NEW THIS SESSION
 
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 ORC PREDICATE PUSHDOWN - SESSION 16 PROGRESS