apache/calcite
Mar 2025 – Mar 2026
10 Months active
Languages Used
JavaYAMLSQL
Technical Skills
Algorithm ImplementationDatabase InternalsDatabase OptimizationDynamic ProgrammingQuery OptimizationQuery Planning
Silun
PROFILE
Silun
Silun Dong contributed to the apache/calcite repository by building advanced query optimization features and resolving complex bugs in SQL planning and execution. Over ten months, Silun designed and implemented algorithms for join reordering, predicate pushdown, and aggregate function handling, using Java and SQL to enhance Calcite’s optimizer. Their work included developing dynamic programming-based join graphs, expanding support for multiple join types, and improving type inference for edge-case aggregations. Silun also addressed reliability issues in sub-query decorrelation and variable scoping, demonstrating depth in compiler development and database internals. The contributions resulted in more efficient, correct, and scalable query planning for Calcite.
Overall Statistics
Feature vs Bugs
67%Features
Repository Contributions
13Total
Bugs
4
Commits
13
Features
8
Lines of code
7,239
Activity Months10
Your Network
97 peopleWork History
March 2026
1 Commits
Mar 1, 2026March 2026: Key bug fix in the decorrelation path of Calcite's query planner. Implemented fix to ensure FilterJoinRule preserves variablesSet during decorrelation, addressing CALCITE-7434. This change improves correctness of decorrelated SQL plans and reduces risk of incorrect results in production queries. Commit 66c496a6a0187f38dcd87e2e20f4449505db8740.
1 Commits
Mar 1, 2026March 2026: Key bug fix in the decorrelation path of Calcite's query planner. Implemented fix to ensure FilterJoinRule preserves variablesSet during decorrelation, addressing CALCITE-7434. This change improves correctness of decorrelated SQL plans and reduces risk of incorrect results in production queries. Commit 66c496a6a0187f38dcd87e2e20f4449505db8740.
March 2026
February 2026
2 Commits • 1 Features
Feb 1, 2026February 2026: Focused on improving Calcite sub-query decorrelation performance and reliability. Delivered a sub-query decorrelation optimization and testing enhancements, including a new sub-query test case and conditional checks for old decorrelation logic to optimize query plans. Fixed a bug in TopDownGeneralDecorrelator when processing aggregate filters, improving reliability for aggregate(col) scenarios. These changes, with commit references, improved query performance and correctness for analytics workloads and expanded test coverage.
February 2026
2 Commits • 1 Features
Feb 1, 2026February 2026: Focused on improving Calcite sub-query decorrelation performance and reliability. Delivered a sub-query decorrelation optimization and testing enhancements, including a new sub-query test case and conditional checks for old decorrelation logic to optimize query plans. Fixed a bug in TopDownGeneralDecorrelator when processing aggregate filters, improving reliability for aggregate(col) scenarios. These changes, with commit references, improved query performance and correctness for analytics workloads and expanded test coverage.
January 2026
1 Commits • 1 Features
Jan 1, 2026January 2026 monthly summary for apache/calcite. Delivered Left-Mark Join support in the Enumerable Convention, enabling preservation of all left rows with markers indicating matches on the right. This work completes the LEFT_MARK type for hash join in the enumerable path (CALCITE-7315) and strengthens correctness and usability of the enumerable execution path for left-outer joins.
1 Commits • 1 Features
Jan 1, 2026January 2026 monthly summary for apache/calcite. Delivered Left-Mark Join support in the Enumerable Convention, enabling preservation of all left rows with markers indicating matches on the right. This work completes the LEFT_MARK type for hash join in the enumerable path (CALCITE-7315) and strengthens correctness and usability of the enumerable execution path for left-outer joins.
January 2026
December 2025
2 Commits • 2 Features
Dec 1, 20252025-12 monthly summary for apache/calcite: Delivered feature and governance updates with clear business value. The primary feature added is null-aware IS NOT DISTINCT FROM support for hash joins, enabling correct NULL semantics in join conditions and improving accuracy of analytics queries. This included null-aware accessors and adjustments to join condition analysis. Commit 19ef7f0b47e97137e37c2956ace8319f2de5e5ce (CALCITE-7327).
December 2025
2 Commits • 2 Features
Dec 1, 20252025-12 monthly summary for apache/calcite: Delivered feature and governance updates with clear business value. The primary feature added is null-aware IS NOT DISTINCT FROM support for hash joins, enabling correct NULL semantics in join conditions and improving accuracy of analytics queries. This included null-aware accessors and adjustments to join condition analysis. Commit 19ef7f0b47e97137e37c2956ace8319f2de5e5ce (CALCITE-7327).
September 2025
1 Commits
Sep 1, 2025In September 2025, focused on reliability and correctness of Calcite’s RelStructuredTypeFlattener path for Project relations. Delivered a targeted bug fix that preserves the VariablesSet across flattening, preventing loss of query variable state during plan construction and execution. The change stabilizes project-node handling in query plans and reduces subtle failures in variable scoping across rewrites.
1 Commits
Sep 1, 2025In September 2025, focused on reliability and correctness of Calcite’s RelStructuredTypeFlattener path for Project relations. Delivered a targeted bug fix that preserves the VariablesSet across flattening, preventing loss of query variable state during plan construction and execution. The change stabilizes project-node handling in query plans and reduces subtle failures in variable scoping across rewrites.
September 2025
August 2025
1 Commits
Aug 1, 2025Concise monthly summary for 2025-08 focusing on business value and technical achievements. Implemented a targeted fix in apache/calcite to address incorrect type inference for aggregate functions when groupSets contains an empty set. Introduced a hasEmptyGroup flag to accurately reflect the presence of empty groups, enabling correct nullability inference for aggregates such as SUM. This work aligns with CALCITE-7134 and includes regression tests to prevent future regressions. The patch was submitted with commit 66afac689ea5b3f59c8050f9a59619c5c5bee771, along with focused validation in the test suite to improve reliability of edge-case aggregations.
August 2025
1 Commits
Aug 1, 2025Concise monthly summary for 2025-08 focusing on business value and technical achievements. Implemented a targeted fix in apache/calcite to address incorrect type inference for aggregate functions when groupSets contains an empty set. Introduced a hasEmptyGroup flag to accurately reflect the presence of empty groups, enabling correct nullability inference for aggregates such as SUM. This work aligns with CALCITE-7134 and includes regression tests to prevent future regressions. The patch was submitted with commit 66afac689ea5b3f59c8050f9a59619c5c5bee771, along with focused validation in the test suite to improve reliability of edge-case aggregations.
July 2025
1 Commits • 1 Features
Jul 1, 2025July 2025 monthly summary for apache/calcite: Delivered AggregateFilterToCaseRule implementing inverse of AggregateCaseToFilterRule to transform aggregate functions with FILTER into CASE statements; this expands optimizer capabilities and enhances plan flexibility. Commit d63996d487d4395cefc65157ef4a5596741bfbcd provides traceable implementation. Impact includes potential performance improvements through richer transformation options and broader applicability of FILTER-driven aggregates. Technologies/skills demonstrated include Java, Calcite optimizer framework, rule-based rewriting, and integration with existing optimization rules.
1 Commits • 1 Features
Jul 1, 2025July 2025 monthly summary for apache/calcite: Delivered AggregateFilterToCaseRule implementing inverse of AggregateCaseToFilterRule to transform aggregate functions with FILTER into CASE statements; this expands optimizer capabilities and enhances plan flexibility. Commit d63996d487d4395cefc65157ef4a5596741bfbcd provides traceable implementation. Impact includes potential performance improvements through richer transformation options and broader applicability of FILTER-driven aggregates. Technologies/skills demonstrated include Java, Calcite optimizer framework, rule-based rewriting, and integration with existing optimization rules.
July 2025
June 2025
1 Commits • 1 Features
Jun 1, 20252025-06 monthly summary for apache/calcite: Implemented multi-join-type support in DPhyp join reorder to handle inner, left, full, semi, and anti joins. Enhanced HyperGraph and DpHyp to properly manage these joins, improving conflict detection and condition extraction for more accurate join ordering on complex queries. This work aligns with CALCITE-7029 and was committed as 7dec961ab9204e0dc9f849a7ae0c0393f5b8dadf. Business value includes broader optimizer capabilities, higher-quality execution plans, and potential performance improvements for complex workloads.
June 2025
1 Commits • 1 Features
Jun 1, 20252025-06 monthly summary for apache/calcite: Implemented multi-join-type support in DPhyp join reorder to handle inner, left, full, semi, and anti joins. Enhanced HyperGraph and DpHyp to properly manage these joins, improving conflict detection and condition extraction for more accurate join ordering on complex queries. This work aligns with CALCITE-7029 and was committed as 7dec961ab9204e0dc9f849a7ae0c0393f5b8dadf. Business value includes broader optimizer capabilities, higher-quality execution plans, and potential performance improvements for complex workloads.
April 2025
1 Commits • 1 Features
Apr 1, 2025April 2025 monthly summary for Apache Calcite: Delivered predicate pushdown rules for filter and join conditions, including disjunction expansion to push predicates to join inputs; refactored common optimization logic into a helper class; added configuration options for both filter and join scenarios. Resulted in improved query planning efficiency, reduced intermediate result sizes, and better resource utilization.
1 Commits • 1 Features
Apr 1, 2025April 2025 monthly summary for Apache Calcite: Delivered predicate pushdown rules for filter and join conditions, including disjunction expansion to push predicates to join inputs; refactored common optimization logic into a helper class; added configuration options for both filter and join scenarios. Resulted in improved query planning efficiency, reduced intermediate result sizes, and better resource utilization.
April 2025
March 2025
2 Commits • 1 Features
Mar 1, 2025March 2025: Focused on enhancing Calcite's query optimization with DPhyp-based join reorder and predicate pushdown, delivering measurable improvements in join order efficiency and pre-join data reduction. Changes centered on the apache/calcite repository, with commits enabling dynamic programming-based join graphs and expanded predicate handling. Business value includes faster analytics, lower data scanned, and more scalable query planning for large datasets across typical Calcite workloads.
March 2025
2 Commits • 1 Features
Mar 1, 2025March 2025: Focused on enhancing Calcite's query optimization with DPhyp-based join reorder and predicate pushdown, delivering measurable improvements in join order efficiency and pre-join data reduction. Changes centered on the apache/calcite repository, with commits enabling dynamic programming-based join graphs and expanded predicate handling. Business value includes faster analytics, lower data scanned, and more scalable query planning for large datasets across typical Calcite workloads.
Activity
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Quality Metrics
Correctness94.6%
Maintainability87.6%
Architecture90.0%
Performance83.0%
AI Usage21.6%
Skills & Technologies
Programming Languages
JavaSQLYAML
Technical Skills
Aggregate FunctionsAlgorithm DesignAlgorithm ImplementationCode RefactoringCompiler DesignCompiler DevelopmentData StructuresDatabase InternalsDatabase ManagementDatabase OptimizationDynamic ProgrammingJavaJoin ReorderingOptimizerQuery Optimization
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