Github user jhuynh1 commented on a diff in the pull request:
https://github.com/apache/geode/pull/591#discussion_r123388223
--- Diff:
geode-core/src/main/java/org/apache/geode/cache/query/internal/CompiledSelect.java
---
@@ -925,79 +917,89 @@ private SelectResults
applyProjectionOnCollection(SelectResults resultSet,
private SelectResults prepareEmptyResultSet(ExecutionContext context,
boolean ignoreOrderBy)
throws TypeMismatchException, AmbiguousNameException {
- // if no projection attributes or '*'as projection attribute
- // & more than one/RunTimeIterator then create a StrcutSet.
- // If attribute is null or '*' & only one RuntimeIterator then create a
- // ResultSet.
- // If single attribute is present without alias name , then create
- // ResultSet
- // Else if more than on attribute or single attribute with alias is
- // present then return a StrcutSet
- // create StructSet which will contain root objects of all iterators in
- // from clause
+ // If no projection attributes or '*' as projection attribute & more
than one/RunTimeIterator
+ // then create a StructSet.
+ // If attribute is null or '*' & only one RuntimeIterator then create
a ResultSet.
+ // If single attribute is present without alias name, then create
ResultSet.
+ // Else if more than on attribute or single attribute with alias is
present then return a
+ // StructSet.
+ // Create StructSet which will contain root objects of all iterators
in from clause.
ObjectType elementType = this.cachedElementTypeForOrderBy != null
? this.cachedElementTypeForOrderBy : prepareResultType(context);
SelectResults results;
- if (this.distinct || !this.count) {
- if (this.orderByAttrs != null) {
- boolean nullValuesAtStart = !((CompiledSortCriterion)
orderByAttrs.get(0)).getCriterion();
- if (elementType.isStructType()) {
- if (ignoreOrderBy) {
- results = this.distinct ? new LinkedStructSet((StructTypeImpl)
elementType)
- : new SortedResultsBag(elementType, nullValuesAtStart);
- } else {
- OrderByComparator comparator = this.hasUnmappedOrderByCols
- ? new OrderByComparatorUnmapped(this.orderByAttrs,
(StructTypeImpl) elementType,
- context)
- : new OrderByComparator(this.orderByAttrs,
(StructTypeImpl) elementType, context);
- results = this.distinct ? new SortedStructSet(comparator,
(StructTypeImpl) elementType)
- : new SortedStructBag(comparator, (StructType)
elementType, nullValuesAtStart);
+ if (!this.distinct && this.count) {
+ // Shobhit: If it's a 'COUNT' query and no End processing required
Like for 'DISTINCT'
+ // we can directly keep count in ResultSet and ResultBag is good
enough for that.
+ countStartQueryResult = 0;
+ return new ResultsBag(new ObjectTypeImpl(Integer.class), 1,
context.getCachePerfStats());
+ }
- }
- } else {
- if (ignoreOrderBy) {
- results =
- this.distinct ? new LinkedResultSet() : new
SortedResultsBag(nullValuesAtStart);
+ // Potential edge-case: Could this be non-null but empty?
+ boolean nullValuesAtStart = orderByAttrs != null &&
!orderByAttrs.get(0).getCriterion();
+ OrderByComparator comparator;
+ switch (convertToStringCase(elementType, ignoreOrderBy)) {
+ case "UNORDERED DISTINCT STRUCT":
+ return new StructSet((StructType) elementType);
+ case "UNORDERED DISTINCT RESULTS":
+ return new ResultsSet(elementType);
+ case "UNORDERED INDISTINCT STRUCT":
+ return new StructBag((StructType) elementType,
context.getCachePerfStats());
+ case "UNORDERED INDISTINCT RESULTS":
+ return new ResultsBag(elementType, context.getCachePerfStats());
+
+ case "ORDERED DISTINCT STRUCT IGNORED":
+ return new LinkedStructSet((StructTypeImpl) elementType);
+ case "ORDERED INDISTINCT STRUCT IGNORED":
+ return new SortedResultsBag(elementType, nullValuesAtStart);
+ case "ORDERED DISTINCT STRUCT UNIGNORED":
--- End diff --
I think the ignoreOrderBy flag is a bit misleading, otherwise UNORDERED
DISTINCT STRUCT should technically be the same as ORDERED DISTINCT STRUCT
IGNORED (since ignoreOrderby is true). It's almost like a "sort at data
structure" level or delay the sort until later flag.
If you decide to keep the naming, would it make sense to not have UNIGNORED
but rather a no string. So ORDERED DISTINCT STRUCT == ORDERED DISTINCT STRUCT
UNIGNORED
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