Github user hbdeshmukh commented on a diff in the pull request:
https://github.com/apache/incubator-quickstep/pull/181#discussion_r104723045
--- Diff: query_optimizer/ExecutionGenerator.cpp ---
@@ -740,6 +805,202 @@ void ExecutionGenerator::convertHashJoin(const
P::HashJoinPtr &physical_plan) {
key_types.push_back(&left_attribute_type);
}
+ const CatalogRelationInfo *build_relation_info =
+ findRelationInfoOutputByPhysical(build_physical);
+ const CatalogRelationInfo *probe_operator_info =
+ findRelationInfoOutputByPhysical(probe_physical);
+
+ const CatalogRelation *build_relation = build_relation_info->relation;
+ const CatalogRelation *probe_relation = probe_operator_info->relation;
+
+ // FIXME(quickstep-team): Add support for self-join.
+ if (build_relation == probe_relation) {
+ THROW_SQL_ERROR() << "Self-join is not supported";
+ }
+
+ const PartitionScheme *build_partition_scheme =
build_relation->getPartitionScheme();
+ const PartitionScheme *probe_partition_scheme =
probe_relation->getPartitionScheme();
+
+ bool build_needs_repartition = false;
+ bool probe_needs_repartition = false;
+ bool needs_swap = false;
+ if (build_partition_scheme && probe_partition_scheme) {
+ const PartitionSchemeHeader &build_partition_scheme_header =
build_partition_scheme->getPartitionSchemeHeader();
+ const PartitionSchemeHeader &probe_partition_scheme_header =
probe_partition_scheme->getPartitionSchemeHeader();
+
+ switch (build_partition_scheme_header.getPartitionType()) {
+ case PartitionSchemeHeader::PartitionType::kRange:
+ build_needs_repartition = true;
+
+ switch (probe_partition_scheme_header.getPartitionType()) {
+ case PartitionSchemeHeader::PartitionType::kRange:
+ probe_needs_repartition = true;
+ break;
+ case PartitionSchemeHeader::PartitionType::kHash: {
+ const attribute_id probe_partition_attr =
probe_partition_scheme_header.getPartitionAttributeId();
+ if (find(probe_attribute_ids.begin(),
probe_attribute_ids.end(), probe_partition_attr) !=
+ probe_attribute_ids.end()) {
+ needs_swap = true;
--- End diff --
I am not sure if I agree. Consider the following counterexample.
Original build table - cardinality 10k, range partitioned.
Original probe table - cardinality 1M, hash partitioned.
By the above logic, you will swap the build and probe relations, thereby
building a giant hash table for 1M entries. You are going to repartition the
new probe relation anyway, so that cost isn't avoided.
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