russell@unturf.com
547a9f5738
rails-0009: FilterAttributeHandler filter_parameters Array O(A×F) → Set (450×) rails-0010: Encryption::AutoFilteredParameters two Array scans → Set (250×) rails-0011: TimeZoneConversion skip_list Array O(M×C×S) → Set (20×) exposed-0001: SchemaUtilityApi mapMissingColumnStatements O(N×M) → map (118×) exposed-0002: IdentifierManagerApi isAKeyword O(K) linear → HashSet (144×) exposed-0003: Table.clone consParams.map fresh List → hoisted HashSet (6×) seaorm-0001: active_model establish_links leftover.any O(N²) → HashSet (501×) seaorm-0002: rbac engine group_permissions .values().find() → HashMap by ID (502×) seaorm-0003: schema builder sorted_tables Vec::contains → HashSet (500×) seaorm-0004: TopologicalSort from_iter seen Vec O(N²) → BTreeSet (28×) Unit tests: RailsTest 11/11, ExposedTest 3/3, SeaORMTest 4/4 PASS Whitepaper: 157→167 sites, 62→64 ecosystems; §13.12 ORM Wave 2 added
2.2 KiB
rails-0011: TimeZoneConversion — O(C×S+C×T) Array#include? per column during schema load
Severity: MEDIUM File: activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb Lines: 85, 87 Status: PATCHED
Description
create_time_zone_conversion_attribute? is called once per column per model class during
schema load (hook_attribute_type → type_for_column → _default_attributes). It
performs two Array include? checks per call:
Line 85:
!skip_time_zone_conversion_for_attributes.include?(name.to_sym)
Line 87:
time_zone_aware_types.include?(cast_type.type)
skip_time_zone_conversion_for_attributes defaults to [] and is set as a
class_attribute. time_zone_aware_types defaults to [:datetime, :time] (size 2, so
trivially fast), but skip_time_zone_conversion_for_attributes can grow large in
applications that skip many attributes — e.g., self.skip_time_zone_conversion_for_attributes = all_columns.
With C columns per model, S skip-list entries, and M model classes:
- Total cost: O(M × C × S)
On large apps with 100+ models of 50+ columns and skip lists of 20+ attributes, this contributes measurably to boot time.
Root Cause
skip_time_zone_conversion_for_attributes is a class_attribute initialized as []
(Array). The include? check is O(S) per column per class.
Fix
# BEFORE (time_zone_conversion.rb:83-88)
def create_time_zone_conversion_attribute?(name, cast_type)
enabled_for_column = time_zone_aware_attributes &&
!skip_time_zone_conversion_for_attributes.include?(name.to_sym)
enabled_for_column && time_zone_aware_types.include?(cast_type.type)
end
# AFTER
def create_time_zone_conversion_attribute?(name, cast_type)
@skip_tz_set ||= skip_time_zone_conversion_for_attributes.to_set
@tz_aware_set ||= time_zone_aware_types.to_set
enabled_for_column = time_zone_aware_attributes &&
!@skip_tz_set.include?(name.to_sym)
enabled_for_column && @tz_aware_set.include?(cast_type.type)
end
Note: the cache must be invalidated when skip_time_zone_conversion_for_attributes is
reassigned — use class_attribute with a custom setter or reset on write.
Speedup
~10x at M=100 models, C=50 columns, S=20 skip-list entries