JackieTien97 commented on code in PR #13716:
URL: https://github.com/apache/iotdb/pull/13716#discussion_r1798654083
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iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/transformation/dag/column/AbstractCaseWhenThenColumnTransformer.java:
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@@ -55,108 +55,185 @@ public ColumnTransformer getElseTransformer() {
@Override
public void evaluate() {
- int[] branchIndexForEachRow = new
int[elseTransformer.getColumnCachePositionCount()];
+
+ List<Column> thenColumnList = new ArrayList<>();
+
+ // region evaluate first when
+ ColumnTransformer firstWhenColumnTransformer =
whenThenTransformers.get(0).left;
+ firstWhenColumnTransformer.evaluate();
+ Column firstWhenColumn = firstWhenColumnTransformer.getColumn();
+
+ int positionCount = firstWhenColumn.getPositionCount();
+ boolean[] selection = new boolean[positionCount];
+ Arrays.fill(selection, true);
+
+ int[] branchIndexForEachRow = new int[positionCount];
Arrays.fill(branchIndexForEachRow, -1);
- doTransform(branchIndexForEachRow);
+ boolean[] selectionForThen = selection.clone();
+
+ // 根据第一个 whenColumn更新 branchIndexForEachRow
+ for (int i = 0; i < positionCount; i++) {
+ // 当前行没有匹配的 whenTransformer 时，才更新 selectionForThen 和
branchIndexForEachRow
+ if (branchIndexForEachRow[i] == -1) {
+ if (!firstWhenColumn.isNull(i) && firstWhenColumn.getBoolean(i)) {
+ branchIndexForEachRow[i] = 0;
+ selectionForThen[i] = true;
+ } else {
+ selectionForThen[i] = false;
+ }
+ }
+ }
+
+ ColumnTransformer firstThenColumnTransformer =
whenThenTransformers.get(0).right;
+ firstThenColumnTransformer.evaluateWithSelection(selectionForThen);
+ Column firstThenColumn = firstThenColumnTransformer.getColumn();
+ thenColumnList.add(firstThenColumn);
+
+ // endregion
+
+ // when and then columns
+ for (int i = 1; i < whenThenTransformers.size(); i++) {
+ ColumnTransformer whenColumnTransformer =
whenThenTransformers.get(i).left;
+ whenColumnTransformer.evaluateWithSelection(selection);
+ Column whenColumn = whenColumnTransformer.getColumn();
+
+ selectionForThen = selection.clone();
+
+ // 初始化 selectionForThen
+ for (int j = 0; j < positionCount; j++) {
+ if (branchIndexForEachRow[j] == -1
+ || branchIndexForEachRow[j] == whenThenTransformers.size()) {
+ selectionForThen[j] = false;
+ }
+ }
+
+ // 根据第一个 whenColumn更新 branchIndexForEachRow
+ for (int j = 0; j < positionCount; j++) {
+ // 当前行没有匹配的 whenTransformer 时，才更新 selectionForThen 和
branchIndexForEachRow
+ if (branchIndexForEachRow[j] == -1) {
+ if (!whenColumn.isNull(j) && whenColumn.getBoolean(j)) {
+ branchIndexForEachRow[j] = i;
+ selectionForThen[j] = true;
+ } else {
+ selectionForThen[j] = false;
+ }
+ }
+ }
+
+ ColumnTransformer thenColumnTransformer =
whenThenTransformers.get(i).right;
+ thenColumnTransformer.evaluateWithSelection(selectionForThen);
+ Column thenColumn = thenColumnTransformer.getColumn();
+ thenColumnList.add(thenColumn);
+ }
+
+ // elseColumn
+ doTransform(branchIndexForEachRow, positionCount, thenColumnList);
}
@Override
public void evaluateWithSelection(boolean[] selection) {
+
+ // region initialize branchIndexForEachRow.
+ // branchIndexForEachRow indicates the index of the WhenTransformer
matched by each row.
int[] branchIndexForEachRow = new int[selection.length];
+ // positionCount indicates the length of column
+ int positionCount = selection.length;
+
+ // 赋值为-1表示需要进行求值，否则表示不需要进行求值
for (int i = 0; i < selection.length; i++) {
if (selection[i]) {
branchIndexForEachRow[i] = -1;
} else {
branchIndexForEachRow[i] = whenThenTransformers.size();
}
}
- doTransform(branchIndexForEachRow);
- }
+ // endregion
- private void doTransform(int[] branch) {
- int[] branchIndexForEachRow = null;
List<Column> thenColumnList = new ArrayList<>();
// when and then columns
for (int i = 0; i < whenThenTransformers.size(); i++) {
ColumnTransformer whenColumnTransformer =
whenThenTransformers.get(i).left;
- whenColumnTransformer.tryEvaluate();
+ whenColumnTransformer.evaluateWithSelection(selection);
Column whenColumn = whenColumnTransformer.getColumn();
- int positionCount = whenColumn.getPositionCount();
- boolean[] selection = new boolean[positionCount];
+ boolean[] selectionForThen = selection.clone();
- if (branchIndexForEachRow == null) {
- // init branchIndexForEachRow if it is null
- branchIndexForEachRow = new int[positionCount];
- Arrays.fill(branchIndexForEachRow, -1);
- } else {
- // update selection with branchIndexForEachRow
- for (int j = 0; j < branchIndexForEachRow.length; j++) {
- if (branchIndexForEachRow[j] != -1) {
- selection[j] = true;
- }
+ // 初始化 selectionForThen
+ for (int j = 0; j < positionCount; j++) {
+ if (branchIndexForEachRow[j] == -1
+ || branchIndexForEachRow[j] == whenThenTransformers.size()) {
+ selectionForThen[j] = false;
Review Comment:
why updating selectionForThen in two places? the following for-loop is also
doing such thing.
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