feat: add cost model framework with deref/array support#84
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JohannesLichtenberger merged 2 commits intomasterfrom Jan 29, 2026
Merged
feat: add cost model framework with deref/array support#84JohannesLichtenberger merged 2 commits intomasterfrom
JohannesLichtenberger merged 2 commits intomasterfrom
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January 25, 2026 23:33
Implement a cost model framework for query optimization with support for JSON/JSONiq-specific operations. Components: - CostModel interface with cost estimation and comparison methods - OperatorContext for HFT-style zero-allocation context passing - SimpleCostModel with calibrated cost factors for: - Basic operations: scan, selection, join, sort, group-by - Deref operations: field navigation with depth-based costing - Array operations: access, unboxing, slicing costs Design principles: - ThreadLocal pooling for OperatorContext (no allocation in hot paths) - Primitive fields to avoid boxing overhead - Configurable cost factors via system properties - Cost clamping for robustness (NaN, infinity, negative) Includes comprehensive unit tests for all cost estimation methods.
- Convert SimpleCostModelTest from JUnit 5 to JUnit 4 (project uses JUnit 4) - Fix test pattern for ThreadLocal pooling: compute costs immediately after configuring context since acquire() returns same pooled instance - Fix bug in OperatorContext.forArrayAccess: isArrayAccess should be false for single access, true for full unboxing
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Implement a cost model framework for query optimization with support for JSON/JSONiq-specific operations.
Components:
Design principles:
Includes comprehensive unit tests for all cost estimation methods.