924060929 commented on code in PR #12196:
URL: https://github.com/apache/doris/pull/12196#discussion_r959448704
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fe/fe-core/src/main/java/org/apache/doris/nereids/stats/StatsCalculator.java:
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@@ -250,46 +253,49 @@ private StatsDeriveResult computeLimit(Limit limit) {
}
private StatsDeriveResult computeAggregate(Aggregate aggregate) {
- List<Expression> groupByExprList = aggregate.getGroupByExpressions();
+ List<Expression> groupByExpressions =
aggregate.getGroupByExpressions();
StatsDeriveResult childStats = groupExpression.getCopyOfChildStats(0);
- Map<Slot, ColumnStats> childSlotColumnStatsMap =
childStats.getSlotToColumnStats();
+ Map<Slot, ColumnStats> childSlotToColumnStats =
childStats.getSlotToColumnStats();
long resultSetCount = 1;
- for (Expression expression : groupByExprList) {
- List<SlotReference> slotRefList =
expression.collect(SlotReference.class::isInstance);
+ for (Expression groupByExpression : groupByExpressions) {
+ List<SlotReference> slotReferences =
groupByExpression.collect(SlotReference.class::isInstance);
// TODO: Support more complex group expr.
// For example:
// select max(col1+col3) from t1 group by col1+col3;
- if (slotRefList.size() != 1) {
+ if (slotReferences.size() != 1) {
continue;
}
- SlotReference slotRef = slotRefList.get(0);
- ColumnStats columnStats = childSlotColumnStatsMap.get(slotRef);
+ SlotReference slotReference = slotReferences.get(0);
+ ColumnStats columnStats =
childSlotToColumnStats.get(slotReference);
resultSetCount *= columnStats.getNdv();
}
- Map<Slot, ColumnStats> slotColumnStatsMap = new HashMap<>();
- List<NamedExpression> namedExpressionList =
aggregate.getOutputExpressions();
+ Map<Slot, ColumnStats> slotToColumnStats = Maps.newHashMap();
+ List<NamedExpression> outputExpressions =
aggregate.getOutputExpressions();
// TODO: 1. Estimate the output unit size by the type of corresponding
AggregateFunction
// 2. Handle alias, literal in the output expression list
- for (NamedExpression namedExpression : namedExpressionList) {
- if (namedExpression instanceof SlotReference) {
- slotColumnStatsMap.put((SlotReference) namedExpression, new
ColumnStats());
- }
+ for (NamedExpression outputExpression : outputExpressions) {
+ slotToColumnStats.put(outputExpression.toSlot(), new
ColumnStats());
}
- StatsDeriveResult statsDeriveResult = new
StatsDeriveResult(resultSetCount, slotColumnStatsMap);
+ StatsDeriveResult statsDeriveResult = new
StatsDeriveResult(resultSetCount, slotToColumnStats);
// TODO: Update ColumnStats properly, add new mapping from output slot
to ColumnStats
return statsDeriveResult;
}
- // TODO: Update data size and min/max value.
+ // TODO: do real project on column stats
private StatsDeriveResult computeProject(Project project) {
- List<NamedExpression> namedExpressionList = project.getProjects();
- List<Slot> slotSet =
namedExpressionList.stream().flatMap(namedExpression -> {
- List<Slot> slotReferenceList =
namedExpression.collect(SlotReference.class::isInstance);
- return slotReferenceList.stream();
- }).collect(Collectors.toList());
- StatsDeriveResult stat = groupExpression.getCopyOfChildStats(0);
- Map<Slot, ColumnStats> slotColumnStatsMap =
stat.getSlotToColumnStats();
- slotColumnStatsMap.entrySet().removeIf(entry ->
!slotSet.contains(entry.getKey()));
- return stat;
+ List<NamedExpression> projections = project.getProjects();
+ Map<Slot, ColumnStats> childColumnStats =
groupExpression.getCopyOfChildStats(0).getSlotToColumnStats();
+ StatsDeriveResult statsDeriveResult =
groupExpression.getCopyOfChildStats(0);
Review Comment:
```suggestion
StatsDeriveResult statsDeriveResult =
groupExpression.getCopyOfChildStats(0);
Map<Slot, ColumnStats> childColumnStats =
statsDeriveResult.getSlotToColumnStats();
```
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