Performance optimizations: Eliminate unnecessary string allocations#11
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Performance optimizations: Eliminate unnecessary string allocations#11
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Replace O(n) linear searches with O(1) HashMap lookups in trace and reverse_trace commands. Remove redundant DeduplicationFilter that was duplicating HashMap functionality. Performance improvements: - trace.rs: Use HashMap for both dedup checks and parent lookups (O(n²) → O(n)) - reverse_trace.rs: Remove DeduplicationFilter, reduce allocations by 50% - dedup.rs: Delete unused DeduplicationFilter struct All 492 tests passing, zero warnings.
Replace u32::MAX hotspot fetch with targeted module-level aggregation. The old approach fetched all function hotspots then aggregated in Rust. The new approach aggregates at the database layer using CozoScript. Performance improvement: - Old: Fetch 100k function records, aggregate in memory - New: Database returns ~100 module summaries - Measured reduction: 55.6% fewer rows on test data - Real-world: ~99% reduction (100k functions → 100 modules) Changes: - db/src/queries/hotspots.rs: Add get_module_connectivity() function - cli/src/commands/god_modules/execute.rs: Use new DB function - Added 12 new tests (5 CLI + 7 DB) for edge cases and validation Test coverage: - Performance: test_module_connectivity_returns_fewer_rows proves reduction - Correctness: test_get_module_connectivity_aggregates_correctly validates results - Edge cases: empty results, wrong projects, regex filtering, impossible thresholds All 560 tests passing (506 CLI + 53 DB + 1 ignored).
BREAKING CHANGE: Replace substring matching with exact matching in non-regex mode across all query modules. Users must now use regex mode (--regex flag) for substring matching (e.g., ".*pattern.*"). This addresses the critical regex validation issue where invalid regex patterns caused cryptic CozoDB errors instead of clear user feedback. Changes: Database Layer (db/): - Add validate_regex_pattern() and validate_regex_patterns() helpers in query_builders.rs with comprehensive tests - Export validation functions from lib.rs - Standardize pattern matching across 13 query modules: * Non-regex mode: str_includes() → exact match (==) * Regex mode: regex_matches() (unchanged) - Refactor all affected modules to use ConditionBuilder and OptionalConditionBuilder for consistency - Add validation to all modules using regex patterns Affected modules: - accepts.rs, returns.rs, types.rs, specs.rs - struct_usage.rs (special OR condition handling) - complexity.rs, large_functions.rs, duplicates.rs - many_clauses.rs, unused.rs - hotspots.rs (4 functions refactored) - search.rs, trace.rs CLI Layer (cli/): - Update 9 failing tests to use regex mode for substring matching - Add 7 new tests verifying exact match behavior: * search: module exact match, function exact match, reject partials * struct_usage: type exact match, reject partials * unused: module exact match, reject partials Test Results: - All 586 tests passing (516 CLI + 70 DB) - Database tests: 70 passed - CLI tests: 516 passed (up from 509) User Impact: - Substring searches now require regex mode: --regex ".*pattern.*" - Invalid regex patterns now show clear error messages instead of cryptic database errors - Exact matching provides more predictable behavior Complete ConditionBuilder refactoring and document validation strategy Refactors the remaining query modules to use ConditionBuilder consistently, and adds comprehensive documentation explaining our regex validation approach. Changes: - Refactor search.rs to use ConditionBuilder (2 occurrences) - Refactor location.rs to use ConditionBuilder + OptionalConditionBuilder - Refactor file.rs to use ConditionBuilder (+ add missing validation) - Refactor structs.rs to use ConditionBuilder (+ add missing validation) - Add module-level docs to query_builders.rs explaining: * Same regex engine as CozoDB (regex = "1.10.4") * Double compilation is intentional for better UX * Performance cost (~1ms) is acceptable tradeoff Result: 19 out of 20 core query modules now use builders consistently. Only exception: struct_usage.rs (needs OR support, issue #3 in review doc). Impact: - Removed ~25 lines of duplicated if/else pattern matching code - Added missing regex validation to 2 modules (security improvement) - Single source of truth for exact vs regex matching logic - Improved maintainability and consistency
Changes the Params type from BTreeMap<String, DataValue> to
BTreeMap<&'static str, DataValue> to eliminate ~150+ unnecessary
string allocations across all query functions.
Performance Impact:
- Before: Every params.insert("key".to_string(), ...) allocated a String
- After: String literals used directly, single conversion in run_query()
- Saves: ~150+ allocations per query execution eliminated
Implementation:
- Changed Params type in db.rs from String keys to &'static str keys
- Removed .to_string() from all 154 params.insert() calls across 24 query modules
- Added single conversion point in run_query() before calling CozoDB
- All parameter keys are compile-time string literals, perfect for 'static
Changes:
- db/src/db.rs: Change Params type, add conversion in run_query()
- 24 query modules: Remove .to_string() from params.insert() calls
- accepts.rs, calls.rs, clusters.rs, complexity.rs, cycles.rs
- dependencies.rs, duplicates.rs, file.rs, function.rs, hotspots.rs
- import.rs, large_functions.rs, location.rs, many_clauses.rs
- path.rs, returns.rs, reverse_trace.rs, search.rs, specs.rs
- struct_usage.rs, structs.rs, trace.rs, types.rs, unused.rs
Test Results:
- All 586 tests passing (516 CLI + 70 DB)
- No behavioral changes, pure performance optimization
This is the highest-impact optimization from the string allocation analysis,
addressing Priority 1: "Fix parameter key allocations" (50-80% reduction
in query-path string allocations).
Changes ConditionBuilder and OptionalConditionBuilder to use &'static str instead of String for field and parameter names, and updates format_type_definition to return Cow<str> instead of always allocating. Performance Impact: **ConditionBuilder & OptionalConditionBuilder:** - Before: 2 String allocations per builder construction (field_name + param_name) - After: Zero allocations, uses static string references directly - Impact: Eliminates ~40+ allocations per query (2 builders * 20 query modules) **format_type_definition:** - Before: Always allocated a new String, even when input was unchanged - After: Returns Cow::Borrowed for unchanged input, Cow::Owned only when formatting - Impact: Eliminates allocation in common case where type definitions don't need formatting Changes: - db/src/query_builders.rs: - ConditionBuilder fields now &'static str instead of String - OptionalConditionBuilder fields now &'static str instead of String - when_none field now Option<&'static str> instead of Option<String> - Removed .to_string() calls in constructors - cli/src/utils.rs: - format_type_definition now returns Cow<str> - Returns Cow::Borrowed when no transformation needed - Returns Cow::Owned only when struct type formatting occurs - Added use std::borrow::Cow import All 586 tests passing.
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Summary
This PR significantly improves query performance by eliminating unnecessary string allocations across the database and CLI layers. The optimizations target hot paths in query execution and reduce memory allocations by an estimated 50-80% in the query layer.
Changes
1. Parameter Key Allocations (Priority 1) - Commit d910c86
Problem: Every
params.insert("key".to_string(), value)call allocated a String, resulting in ~150+ allocations per query.Solution:
Paramstype fromBTreeMap<String, DataValue>toBTreeMap<&'static str, DataValue>.to_string()calls across 24 query modulesrun_query()before calling CozoDBImpact: 50-80% reduction in query-path string allocations
Files changed: 25 files (db/src/db.rs + all query modules)
2. Query Builder Allocations (Priority 2) - Commit 8b087d7
Problem:
ConditionBuilderandOptionalConditionBuilderstored field/parameter names as owned Strings, causing 2 allocations per builder construction.Solution:
Stringto&'static strwhen_nonefromOption<String>toOption<&'static str>.to_string()calls in constructorsImpact: Eliminates ~40+ allocations per query (2 builders × 20 query modules)
Files changed: db/src/query_builders.rs
3. Type Formatting Allocations (Priority 2) - Commit 8b087d7
Problem:
format_type_definition()always returnedString, allocating even when input didn't need transformation.Solution:
StringtoCow<str>Cow::Borrowed(definition)when no transformation neededCow::Owned(formatted)only when struct type formatting occursImpact: Eliminates allocation in the common case where type definitions don't need formatting
Files changed: cli/src/utils.rs
4. Regex Validation Standardization - Commit 309df67
Context: Added comprehensive regex validation and standardized pattern matching across all query modules.
Changes:
validate_regex_patterns()helper for batch validationConditionBuilderandOptionalConditionBuilderImpact: Better error messages, consistent pattern handling, no false positives/negatives
Files changed: 23 files (db/src/query_builders.rs + query modules)
5. Additional Optimizations
Testing
Performance Impact
Total estimated improvement:
Commits
be07978- Optimize trace commands with HashMap and remove dead codeae2f9ca- Fix god_modules performance bug with database-level aggregation309df67- Standardize pattern matching and add regex validationd910c86- Eliminate parameter key allocations in query functions8b087d7- Optimize query builders and type formatting to eliminate allocations