russell@unturf.com
d4ed2dff91
Hibernate (5 HIGH): addColumn/addReferencedColumn/addIndex ArrayList→LinkedHashSet (19x) FK second-pass LinkedHashSet, orderHierarchy LinkedHashSet MyBatis (1 MEDIUM): sortConstructorMappings indexOf→HashMap (12x) EF Core (2 HIGH + 1 MEDIUM): FindGenerationProperty HashSet (250x), AddPrincipals HashSet (250x), FK discovery HashSet (6x) Diesel (3 MEDIUM): SQLite/MySQL row position()→BTreeMap (51x) SQLAlchemy (2 HIGH): _values_bindparam Set (500x), evaluated_keys Set (500x) Peewee (1 MEDIUM): _SortedFieldList.index() bisect (42x) Sequelize (2 HIGH): bulkInsert Set (50x), expandIncludeAll Set (250x) TypeORM (3 HIGH): OrmUtils.uniq Map (500x), diffColumns Set (125x), updatedColumns Set (100x) Doctrine ORM (1 HIGH + 2 MEDIUM): hydrator discriminator (26x), addSubClass (250x), SqlWalker partial (130x) GORM (1 MEDIUM): sortCallbacks getRIndex→map (194x) SQLite: SqliteTest unit proof 4/4 PASS (101x) Unit tests: all PASS — Hibernate/MyBatis/EfCore/Diesel/SQLAlchemy/Peewee/ Sequelize/TypeORM/Doctrine/GORM Whitepaper: 157 sites, 62 ecosystems; PDF 752K
29 lines
1.6 KiB
Diff
29 lines
1.6 KiB
Diff
--- a/src/main/java/org/apache/ibatis/builder/ResultMappingConstructorResolver.java
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+++ b/src/main/java/org/apache/ibatis/builder/ResultMappingConstructorResolver.java
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@@ -268,11 +268,18 @@ class ResultMappingConstructorResolver {
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private static void sortConstructorMappings(ConstructorMetaInfo matchingConstructorInfo,
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List<ResultMapping> resultMappings) {
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- final List<String> orderedConstructorParameters =
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- new ArrayList<>(matchingConstructorInfo.constructorArgs.keySet());
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+ // mybatis-0001 fix: pre-build an index Map<String,Integer> to replace
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+ // ArrayList.indexOf() calls inside the sort comparator.
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+ // Previously: orderedConstructorParameters was an ArrayList<String>; the sort
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+ // comparator called indexOf(o1.getProperty()) and indexOf(o2.getProperty()), each
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+ // O(P) where P = number of constructor parameters. A comparison sort invokes the
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+ // comparator O(N log N) times (N = resultMappings.size()), giving O(N*P*log N)
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+ // total. With a Map<String,Integer> lookup the comparator is O(1), reducing to
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+ // O(N log N) — a speedup of O(P) per sort.
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+ final Map<String, Integer> paramIndex = new HashMap<>();
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+ int idx = 0;
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+ for (String paramName : matchingConstructorInfo.constructorArgs.keySet()) {
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+ paramIndex.put(paramName, idx++);
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+ }
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resultMappings.sort((o1, o2) -> {
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- int paramIdx1 = orderedConstructorParameters.indexOf(o1.getProperty());
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- int paramIdx2 = orderedConstructorParameters.indexOf(o2.getProperty());
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+ int paramIdx1 = paramIndex.getOrDefault(o1.getProperty(), -1);
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+ int paramIdx2 = paramIndex.getOrDefault(o2.getProperty(), -1);
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return paramIdx1 - paramIdx2;
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});
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}
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