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Commit f9dfb6b

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epochcoderepochcoder
committed
mybatis#101: Drastically improve performance by only checking if we can create the result once
Given that the mapping of the next rows would be identical, this is safe
1 parent 5be1b0c commit f9dfb6b
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‎src/main/java/org/apache/ibatis/executor/resultset/DefaultResultSetHandler.java‎

Copy file name to clipboardExpand all lines: src/main/java/org/apache/ibatis/executor/resultset/DefaultResultSetHandler.java
+22-16Lines changed: 22 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -1035,12 +1035,17 @@ private String prependPrefix(String columnName, String prefix) {
10351035
private void handleRowValuesForNestedResultMap(ResultSetWrapper rsw, ResultMap resultMap,
10361036
ResultHandler<?> resultHandler, RowBounds rowBounds, ResultMapping parentMapping) throws SQLException {
10371037
final boolean useCollectionConstructorInjection = resultMap.hasResultMapsUsingConstructorCollection();
1038+
boolean verifyPendingCreationResult = true;
1039+
PendingConstructorCreation lastHandledCreation = null;
1040+
if (useCollectionConstructorInjection) {
1041+
verifyPendingCreationPreconditions(parentMapping);
1042+
}
1043+
10381044
final DefaultResultContext<Object> resultContext = new DefaultResultContext<>();
10391045
ResultSet resultSet = rsw.getResultSet();
10401046
skipRows(resultSet, rowBounds);
10411047
Object rowValue = previousRowValue;
10421048

1043-
PendingConstructorCreation lastHandledCreation = null;
10441049
while (shouldProcessMoreRows(resultContext, rowBounds) && !resultSet.isClosed() && resultSet.next()) {
10451050
final ResultMap discriminatedResultMap = resolveDiscriminatedResultMap(resultSet, resultMap, null);
10461051
final CacheKey rowKey = createRowKey(discriminatedResultMap, rsw, null);
@@ -1051,8 +1056,12 @@ private void handleRowValuesForNestedResultMap(ResultSetWrapper rsw, ResultMap r
10511056
// issue #577, #542 && #101
10521057
if (useCollectionConstructorInjection) {
10531058
if (foundNewUniqueRow && lastHandledCreation != null) {
1054-
createAndStorePendingCreation(resultHandler, parentMapping, resultSet, resultContext, lastHandledCreation);
1059+
createAndStorePendingCreation(resultHandler, resultSet, resultContext, lastHandledCreation,
1060+
verifyPendingCreationResult);
10551061
lastHandledCreation = null;
1062+
// we only need to verify the first the result for a given result set
1063+
// as we can assume the next result will look exactly the same w.r.t its mapping
1064+
verifyPendingCreationResult = false;
10561065
}
10571066

10581067
rowValue = getRowValue(rsw, discriminatedResultMap, rowKey, null, partialObject);
@@ -1074,7 +1083,8 @@ private void handleRowValuesForNestedResultMap(ResultSetWrapper rsw, ResultMap r
10741083
}
10751084

10761085
if (useCollectionConstructorInjection && lastHandledCreation != null) {
1077-
createAndStorePendingCreation(resultHandler, parentMapping, resultSet, resultContext, lastHandledCreation);
1086+
createAndStorePendingCreation(resultHandler, resultSet, resultContext, lastHandledCreation,
1087+
verifyPendingCreationResult);
10781088
} else if (rowValue != null && mappedStatement.isResultOrdered()
10791089
&& shouldProcessMoreRows(resultContext, rowBounds)) {
10801090
storeObject(resultHandler, resultContext, rowValue, parentMapping, resultSet);
@@ -1221,26 +1231,22 @@ private boolean applyNestedPendingConstructorCreations(ResultSetWrapper rsw, Res
12211231
return foundValues;
12221232
}
12231233

1224-
private void verifyPendingCreationResultOrdered() {
1234+
private void verifyPendingCreationPreconditions(ResultMapping parentMapping) {
1235+
if (parentMapping != null) {
1236+
throw new ExecutorException(
1237+
"Cannot construct objects with collections in constructors using multiple result sets yet!");
1238+
}
1239+
12251240
if (!mappedStatement.isResultOrdered()) {
12261241
throw new ExecutorException("Cannot reliably construct result if we are not sure the results are ordered "
12271242
+ "so that no new previous rows would occur, set resultOrdered on your mapped statement if you have verified this");
12281243
}
12291244
}
12301245

1231-
private void createAndStorePendingCreation(ResultHandler<?> resultHandler, ResultMapping parentMapping,
1232-
ResultSet resultSet, DefaultResultContext<Object> resultContext, PendingConstructorCreation pendingCreation)
1246+
private void createAndStorePendingCreation(ResultHandler<?> resultHandler, ResultSet resultSet,
1247+
DefaultResultContext<Object> resultContext, PendingConstructorCreation pendingCreation, boolean shouldVerify)
12331248
throws SQLException {
1234-
if (parentMapping != null) {
1235-
throw new ExecutorException("Not supported in immutable constructor mode yet!");
1236-
}
1237-
1238-
verifyPendingCreationResultOrdered();
1239-
1240-
// todo: we can do this verification once per result type in the future
1241-
pendingCreation.verifyCanCreate(objectFactory);
1242-
final Object result = pendingCreation.create(objectFactory);
1243-
1249+
final Object result = pendingCreation.create(objectFactory, shouldVerify);
12441250
storeObject(resultHandler, resultContext, result, null, resultSet);
12451251
nestedResultObjects.clear();
12461252
}
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‎src/main/java/org/apache/ibatis/executor/resultset/PendingConstructorCreation.java‎

Copy file name to clipboardExpand all lines: src/main/java/org/apache/ibatis/executor/resultset/PendingConstructorCreation.java
+9-4Lines changed: 9 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -107,7 +107,7 @@ void linkCollectionValue(ResultMapping constructorMapping, Object value) {
107107
* @param objectFactory
108108
* the object factory
109109
*/
110-
void verifyCanCreate(ObjectFactory objectFactory) {
110+
private void verifyCanCreate(ObjectFactory objectFactory) {
111111
// before we create, we need to get the constructor to be used and verify our types match
112112
// since we added to the collection completely unchecked
113113
final Constructor<?> resolvedConstructor = objectFactory.resolveConstructor(resultType, constructorArgTypes);
@@ -168,10 +168,16 @@ public String toString() {
168168
*
169169
* @param objectFactory
170170
* the object factory
171+
* @param verifyCreate
172+
* should we verify this object can be created, should only be needed once
171173
*
172174
* @return the new immutable result
173175
*/
174-
Object create(ObjectFactory objectFactory) {
176+
Object create(ObjectFactory objectFactory, boolean verifyCreate) {
177+
if (verifyCreate) {
178+
verifyCanCreate(objectFactory);
179+
}
180+
175181
final List<Object> newArguments = new ArrayList<>(constructorArgs.size());
176182
for (int i = 0; i < constructorArgs.size(); i++) {
177183
final PendingCreationMetaInfo creationMetaInfo = linkedCollectionMetaInfo.get(i);
@@ -191,8 +197,7 @@ Object create(ObjectFactory objectFactory) {
191197
final List<PendingConstructorCreation> linkedCreations = linkedCreationsByResultMapId.get(resultMapId);
192198

193199
for (PendingConstructorCreation linkedCreation : linkedCreations) {
194-
linkedCreation.verifyCanCreate(objectFactory);
195-
emptyCollection.add(linkedCreation.create(objectFactory));
200+
emptyCollection.add(linkedCreation.create(objectFactory, verifyCreate));
196201
}
197202

198203
newArguments.add(emptyCollection);

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