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⚡ Bolt: [performance improvement] O(1) column position tracking#631

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bolt-dbml-import-optimization-10360848842948572850
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⚡ Bolt: [performance improvement] O(1) column position tracking#631
seonghobae wants to merge 1 commit into
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bolt-dbml-import-optimization-10360848842948572850

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💡 What: Replaced an inline O(N) generator expression (sum(1 for ...)) inside a loop with an O(1) dictionary counter for tracking column positions during DBML parsing.
🎯 Why: The original logic had O(N^2) time complexity, creating a performance bottleneck when parsing DBML schemas with a large number of columns in a single table.
📊 Impact: Reduces time complexity of column position parsing from O(N^2) to O(N), which will significantly improve processing time for large DBML files.
🔬 Measurement: Verified using backend test suite (pytest) to ensure functional parity. Performance improvement scales non-linearly with DBML table size.


PR created automatically by Jules for task 10360848842948572850 started by @seonghobae

💡 What: Replaced an inline O(N) generator expression (`sum(1 for ...)`) inside a loop with an O(1) dictionary counter for tracking column positions during DBML parsing.
🎯 Why: The original logic had O(N^2) time complexity, creating a performance bottleneck when parsing DBML schemas with a large number of columns in a single table.
📊 Impact: Reduces time complexity of column position parsing from O(N^2) to O(N), which will significantly improve processing time for large DBML files.
🔬 Measurement: Verified using backend test suite (pytest) to ensure functional parity. Performance improvement scales non-linearly with DBML table size.
Copilot AI review requested due to automatic review settings July 24, 2026 01:52
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Pull request overview

Optimizes the DBML importer in the backend spec pipeline by making column position tracking O(1) per parsed column, reducing overall parsing time for large DBML tables.

Changes:

  • Replaced per-column sum(1 for ...) counting with a per-table dict[int, int] counter to compute column_position in O(1).
  • Added a Bolt learning note documenting the optimization pattern.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File Description
backend/app/spec/dbml_import.py Uses a per-relation counter to assign column_position in O(1) during DBML parsing.
.Jules/bolt.md Records the performance learning/action for avoiding O(n²) counting in parsing loops.

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Comment thread .Jules/bolt.md
## 2025-06-27 - [Map Initialization Overhead]
**Learning:** Initializing Maps with `new Map(array.map(...))` creates unnecessary intermediate arrays, consuming memory and triggering garbage collection overhead, especially noticeable when dealing with many nodes.
**Action:** Use a `for...of` loop to directly `map.set()` elements rather than creating an intermediate array of tuples, especially in frequently executed or rendering paths.
## $(date +%Y-%m-%d) - [O(1) Dictionary Lookup for DBML parsing]
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2 participants