Coverage for src/lexigram/admin/data/optimizer.py: 0%

1"""Query optimization and analysis for performance tuning.""" 

2 

3from __future__ import annotations 

4 

5from dataclasses import dataclass 

6 

7from lexigram.admin.data.query import QuerySpec 

8 

9 

10@dataclass 

11class QueryAnalysis: 

12 """Results of query performance analysis.""" 

13 

14 estimated_rows: int 

15 uses_index: bool 

16 cost: float 

17 suggestions: list[str] 

18 execution_plan: str 

19 

20 

21class QueryOptimizer: 

22 """Analyzes and optimizes Admin Queries.""" 

23 

24 def analyze(self, query: QuerySpec) -> QueryAnalysis: 

25 """ 

26 Analyze a query and provide performance suggestions. 

27 In a real system, this would interact with the DB explain plan. 

28 """ 

29 suggestions = [] 

30 

31 # 1. Check for missing indexes in filters 

32 conditions = query.filter_conditions 

33 if conditions: 

34 for condition in conditions: 

35 field = condition.field 

36 # Placeholder logic: suspect fields without common index suffixes 

37 if not any(field.endswith(s) for s in ["_id", "_at", "status", "slug"]): 

38 suggestions.append( 

39 f"Field '{field}' used in filter may require an index.", 

40 ) 

41 

42 # 2. Check for large offsets 

43 offset = (query.page - 1) * query.per_page 

44 if offset > 1000: 

45 suggestions.append( 

46 "Large offset detected. Consider cursor-based pagination for better performance.", 

47 ) 

48 

49 # 3. Check for select * 

50 if not query.select_fields: 

51 suggestions.append( 

52 "No specific fields selected. Selecting only required fields can reduce data transfer.", 

53 ) 

54 

55 return QueryAnalysis( 

56 estimated_rows=100, # Mock 

57 uses_index=True, 

58 cost=0.5, 

59 suggestions=suggestions, 

60 execution_plan="mock execution plan", 

61 ) 

62 

63 def optimize(self, query: QuerySpec) -> QuerySpec: 

64 """Apply automatic optimizations to the query.""" 

65 # Example: Automatically add a default limit if none exists 

66 if query.per_page is None: 

67 # We would return a copy with limit set 

68 pass 

69 

70 return query