- Enhanced EnsureCompleteMetadata() to fully load ORC file metadata
- Opens ORC reader if not provided, with recursive call pattern
- Reads and validates physical schema from ORC file
- Initializes stripes_ with all stripes if not already set
- Gets ORC type tree and builds OrcSchemaManifest
- Initializes StripeStatisticsCache with per-stripe guarantees
- Validates stripe indices against file's total stripe count
- Thread-safe with mutex locking (physical_schema_mutex_)

Implementation notes:
- Follows Parquet's EnsureCompleteMetadata pattern closely
- Handles recursive call when reader is null (unlock, open, recurse)
- Casts void* reader to ORCFileReader* for method access
- Statistics cache initialized with literal(true) per stripe
- All stripe-level metadata loaded in one function call

Verified: Manual code review following Parquet reference (lines 802-870)

Co-Authored-By: Claude Sonnet 4.5 <[email protected]>

- Enhanced EnsureCompleteMetadata() to fully load ORC file metadata
- Opens ORC reader if not provided, with recursive call pattern
- Reads and validates physical schema from ORC file
- Initializes stripes_ with all stripes if not already set
- Gets ORC type tree and builds OrcSchemaManifest
- Initializes StripeStatisticsCache with per-stripe guarantees
- Validates stripe indices against file's total stripe count
- Thread-safe with mutex locking (physical_schema_mutex_)

Implementation notes:
- Follows Parquet's EnsureCompleteMetadata pattern closely
- Handles recursive call when reader is null (unlock, open, recurse)
- Casts void* reader to ORCFileReader* for method access
- Statistics cache initialized with literal(true) per stripe
- All stripe-level metadata loaded in one function call

Verified: Manual code review following Parquet reference (lines 802-870)

Co-authored-by: Claude Sonnet 4.5 <[email protected]>

Implemented the OrcFileFragment class structure with ORC-specific predicate
pushdown capabilities. This mirrors ParquetFileFragment design but adapted
for ORC's stripe-based organization.

Added structures:
- OrcFileMetadata: Holds file-level metadata (stripe info, row counts, schema)
  Unlike Parquet's rich FileMetaData, ORC metadata is accessed through reader
  methods, so we cache essentials here.
- StripeStatisticsCache: Cache for stripe-level statistics and guarantees.
  Stores derived guarantee expressions, tracks processed fields, and maintains
  per-column completion flags.
- CacheStatus enum: Tracks lazy metadata loading state (uncached/loading/cached)

OrcFileFragment class:
- Extends FileFragment with stripe-level filtering
- Fields: stripes_ (optional selected indices), metadata_, manifest_,
  statistics_cache_, cache_status_
- Public methods: SplitByStripe, stripes(), metadata(), EnsureCompleteMetadata,
  ClearCachedMetadata, Subset (two overloads)
- Private methods: SetMetadata, FilterStripes, TestStripes, TryCountRows
- Method implementations are stubs with TODO references to future tasks

Key design decisions:
- Mirrors Parquet's row_groups → stripes mapping
- Thread safety via physical_schema_mutex_ (inherited from FileFragment)
- Lazy metadata loading with cache status tracking
- Forward declarations for adapters::orc types to avoid circular dependencies

All public methods documented with detailed comments explaining parameters,
return values, and intended usage patterns.

VERIFICATION STATUS: Build/test verification pending due to network
restrictions preventing CMake from downloading dependencies. Implementation
follows ParquetFileFragment patterns exactly. Methods are stubs that will
be implemented in subsequent tasks (#6-#18).

Co-authored-by: Claude Sonnet 4.5 <[email protected]>

Implemented the OrcFileFragment class structure with ORC-specific predicate
pushdown capabilities. This mirrors ParquetFileFragment design but adapted
for ORC's stripe-based organization.

Added structures:
- OrcFileMetadata: Holds file-level metadata (stripe info, row counts, schema)
  Unlike Parquet's rich FileMetaData, ORC metadata is accessed through reader
  methods, so we cache essentials here.
- StripeStatisticsCache: Cache for stripe-level statistics and guarantees.
  Stores derived guarantee expressions, tracks processed fields, and maintains
  per-column completion flags.
- CacheStatus enum: Tracks lazy metadata loading state (uncached/loading/cached)

OrcFileFragment class:
- Extends FileFragment with stripe-level filtering
- Fields: stripes_ (optional selected indices), metadata_, manifest_,
  statistics_cache_, cache_status_
- Public methods: SplitByStripe, stripes(), metadata(), EnsureCompleteMetadata,
  ClearCachedMetadata, Subset (two overloads)
- Private methods: SetMetadata, FilterStripes, TestStripes, TryCountRows
- Method implementations are stubs with TODO references to future tasks

Key design decisions:
- Mirrors Parquet's row_groups → stripes mapping
- Thread safety via physical_schema_mutex_ (inherited from FileFragment)
- Lazy metadata loading with cache status tracking
- Forward declarations for adapters::orc types to avoid circular dependencies

All public methods documented with detailed comments explaining parameters,
return values, and intended usage patterns.

VERIFICATION STATUS: Build/test verification pending due to network
restrictions preventing CMake from downloading dependencies. Implementation
follows ParquetFileFragment patterns exactly. Methods are stubs that will
be implemented in subsequent tasks (#6-#18).

Co-authored-by: Claude Sonnet 4.5 <[email protected]>

- Extended ConvertColumnStatistics to handle Boolean, Date, Timestamp, and Decimal types
- Boolean: populated num_values from getTrueCount + getFalseCount (no min/max)
- Date: Date32Scalar from int32_t days since epoch
- Timestamp: TimestampScalar with nanosecond precision (millis * 1M + nanos)
- Decimal: Decimal128Scalar from ORC Int128 value with scale

Added 3 new passing tests:
- GetColumnStatisticsBoolean: verifies num_values, has_min_max=false
- GetColumnStatisticsDate: verifies Date32Scalar min/max conversion
- GetColumnStatisticsTimestamp: verifies TimestampScalar min/max conversion

Verified: build and tests pass
Types supported: int, double, string, bool, date, timestamp (6 types)

Co-authored-by: Claude Sonnet 4.5 <[email protected]>