clintropolis commented on code in PR #19460:
URL: https://github.com/apache/druid/pull/19460#discussion_r3352551122
##########
processing/src/main/java/org/apache/druid/segment/QueryableIndexCursorFactory.java:
##########
@@ -110,9 +145,354 @@ public List<AggregatorFactory>
getAggregatorsForPreAggregated()
};
}
+ private CursorHolder makeClusteredCursorHolder(CursorBuildSpec spec,
ClusteredValueGroupsBaseTableSchema clusterSummary)
+ {
+ final ClusterGroupQueryPlan plan = Projections.planClusterGroupQuery(
+ new ArrayList<>(index.getClusterGroupSchemas()),
+ spec
+ );
+
+ if (plan.survivingGroups().isEmpty()) {
+ return EmptyClusteredCursorHolder.INSTANCE;
+ }
+
+ if (plan.survivingGroups().size() == 1) {
+ return makeSingleGroupClusteredCursorHolder(spec, plan,
plan.survivingGroups().get(0));
+ }
+ return makeMultiGroupClusteredCursorHolder(spec, plan);
+ }
+
+ /**
+ * Rebuild {@code spec} for the per-group cursor holder of {@code
valueGroup}, swapping in the plan's per-group
+ * filter rewrite: clustering-column leaves become {@link
org.apache.druid.segment.filter.TrueFilter} /
+ * {@link org.apache.druid.segment.filter.FalseFilter} per the group's
constant clustering tuple and fold through
+ * AND / OR / NOT, so the per-group {@link QueryableIndex}'s filter
machinery never tries to look up indexes for
+ * clustering columns it doesn't physically carry. Selector-side access to
clustering columns (SELECT / GROUP BY)
+ * is still served by {@link ClusteringColumnSelectorFactory} below.
+ */
+ private static CursorBuildSpec rebuildSpecForGroup(
+ CursorBuildSpec spec,
+ ClusterGroupQueryPlan plan,
+ TableClusterGroupSpec valueGroup
+ )
+ {
+ if (spec.getFilter() == null) {
+ return spec;
+ }
+ final Filter rewritten = plan.rewriteFor(valueGroup);
+ if (rewritten == spec.getFilter()) {
+ return spec;
+ }
+ return CursorBuildSpec.builder(spec).setFilter(rewritten).build();
+ }
+
+ private CursorHolder makeSingleGroupClusteredCursorHolder(
+ CursorBuildSpec spec,
+ ClusterGroupQueryPlan plan,
+ TableClusterGroupSpec valueGroup
+ )
+ {
+ final QueryableIndex groupIndex =
index.getClusterGroupQueryableIndex(valueGroup);
+ if (groupIndex == null) {
+ throw DruidException.defensive(
+ "No cluster-group sub-index resolvable for clustering values "
+ + Arrays.toString(valueGroup.lookupClusteringValues())
+ );
+ }
+
+ return new QueryableIndexCursorHolder(
+ groupIndex,
+ rebuildSpecForGroup(spec, plan, valueGroup),
+ QueryableIndexTimeBoundaryInspector.create(groupIndex)
+ )
+ {
+ @Override
+ protected ColumnSelectorFactory makeColumnSelectorFactoryForOffset(
+ ColumnCache columnCache,
+ Offset baseOffset
+ )
+ {
+ return new ClusteringColumnSelectorFactory(
+ super.makeColumnSelectorFactoryForOffset(columnCache, baseOffset),
+ valueGroup.getSummary().getClusteringColumns(),
+ valueGroup.lookupClusteringValues()
+ );
+ }
+
+ @Override
+ protected VectorColumnSelectorFactory
makeVectorColumnSelectorFactoryForOffset(
+ ColumnCache columnCache,
+ VectorOffset baseOffset
+ )
+ {
+ return new ClusteringVectorColumnSelectorFactory(
+ super.makeVectorColumnSelectorFactoryForOffset(columnCache,
baseOffset),
+ valueGroup.getSummary().getClusteringColumns(),
+ valueGroup.lookupClusteringValues()
+ );
+ }
+ };
+ }
+
+ /**
+ * Build a cursor holder that walks multiple matching cluster groups
back-to-back via
+ * {@link ConcatenatingCursor}. Each per-group {@link CursorHolder} is built
lazily inside the cursor's group
+ * transition, so a query that finishes early (e.g., LIMIT-bounded) doesn't
open every group's offset.
+ */
+ private CursorHolder makeMultiGroupClusteredCursorHolder(
+ CursorBuildSpec spec,
+ ClusterGroupQueryPlan plan
+ )
+ {
+ final List<TableClusterGroupSpec> matching = plan.survivingGroups();
+ // All matching specs share the same parent summary (they came out of one
segment); grab a reference for
+ // getOrdering() and clusteringColumns below.
+ final ClusteredValueGroupsBaseTableSchema clusterSummary =
matching.get(0).getSummary();
+ final RowSignature clusteringColumns =
clusterSummary.getClusteringColumns();
+ final List<Object[]> clusteringValuesByGroup = new
ArrayList<>(matching.size());
+ final List<Supplier<CursorHolder>> holderSuppliers = new
ArrayList<>(matching.size());
+ // lifecycle management closer for per-group CursorHolders
+ final Closer closer = Closer.create();
+ for (TableClusterGroupSpec valueGroup : matching) {
+ clusteringValuesByGroup.add(valueGroup.lookupClusteringValues());
+ final QueryableIndex groupIndex =
index.getClusterGroupQueryableIndex(valueGroup);
+ if (groupIndex == null) {
+ throw DruidException.defensive(
+ "No cluster-group sub-index resolvable for clustering values "
+ + Arrays.toString(valueGroup.lookupClusteringValues())
+ );
+ }
+ final CursorBuildSpec groupSpec = rebuildSpecForGroup(spec, plan,
valueGroup);
+ holderSuppliers.add(
+ Suppliers.memoize(
+ () -> closer.register(
+ new QueryableIndexCursorHolder(
+ groupIndex,
+ groupSpec,
+ QueryableIndexTimeBoundaryInspector.create(groupIndex)
+ )
+ )
+ )
+ );
+ }
+
+ // Initial wrapper state uses the first group's clustering values + a
throwing placeholder delegate. The
+ // ConcatenatingCursor immediately calls setDelegate on init (before any
selector is exposed). The vector
+ // wrapper carries the query-level max vector size from the build spec,
the placeholder delegate can't be
+ // queried for sizing, and the value is constant across groups anyway.
+ final int vectorSize = spec.getQueryContext().getVectorSize();
+ final ClusteringColumnSelectorFactory wrapperFactory = new
ClusteringColumnSelectorFactory(
+ UNINITIALIZED_DELEGATE,
+ clusteringColumns,
+ clusteringValuesByGroup.get(0)
+ );
Review Comment:
as mentioned in other comment this is because the delegate also does
metadata stuff, so kind of always needs to work.
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