Jackie-Jiang commented on code in PR #16308:
URL: https://github.com/apache/pinot/pull/16308#discussion_r2208513907
##########
pinot-core/src/main/java/org/apache/pinot/core/operator/combine/GroupByCombineOperator.java:
##########
@@ -99,11 +113,83 @@ public String toExplainString() {
return EXPLAIN_NAME;
}
+ /// merge sorted segment results
+ private void processSafeTrim() {
Review Comment:
We can probably also compare sequential merge performance given the merge
should be very cheap with low `limit`
##########
pinot-core/src/main/java/org/apache/pinot/core/query/request/context/QueryContext.java:
##########
@@ -541,6 +545,20 @@ public boolean isUnsafeTrim() {
return _isUnsafeTrim;
}
+ public boolean shouldSortAggregate() {
+ return !isUnsafeTrim() && _limit <
Server.DEFAULT_SORT_AGGREGATE_LIMIT_THRESHOLD;
+ }
+
+ public Comparator<Key> getGroupKeyComparator() {
Review Comment:
Is this used?
##########
pinot-core/src/main/java/org/apache/pinot/core/query/request/context/QueryContext.java:
##########
@@ -541,6 +545,20 @@ public boolean isUnsafeTrim() {
return _isUnsafeTrim;
}
+ public boolean shouldSortAggregate() {
+ return !isUnsafeTrim() && _limit <
Server.DEFAULT_SORT_AGGREGATE_LIMIT_THRESHOLD;
Review Comment:
Let's make this threshold configurable, similar to other group-by thresholds
##########
pinot-core/src/main/java/org/apache/pinot/core/operator/combine/GroupByCombineOperator.java:
##########
@@ -80,11 +88,17 @@ public GroupByCombineOperator(List<Operator> operators,
QueryContext queryContex
_numGroupByExpressions = _queryContext.getGroupByExpressions().size();
_numColumns = _numGroupByExpressions + _numAggregationFunctions;
_operatorLatch = new CountDownLatch(_numTasks);
+ if (_queryContext.shouldSortAggregate()) {
Review Comment:
Consider adding a new combine operator for this new logic. Mixing 2 logic in
1 combine operator is not very readable
##########
pinot-core/src/main/java/org/apache/pinot/core/query/request/context/QueryContext.java:
##########
@@ -182,8 +187,7 @@ private boolean isSameOrderAndGroupByColumns(QueryContext
context) {
}
/**
- * Returns the table name.
- * NOTE: on the broker side, table name might be {@code null} when subquery
is available.
+ * Returns the table name. NOTE: on the broker side, table name might be
{@code null} when subquery is available.
Review Comment:
Seems there are several unrelated reformat. Suggest reverting them
##########
pinot-core/src/main/java/org/apache/pinot/core/data/table/LinkedHashMapIndexedTable.java:
##########
@@ -0,0 +1,226 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.core.data.table;
+
+import java.util.Comparator;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import org.apache.pinot.common.utils.DataSchema;
+import org.apache.pinot.core.operator.blocks.results.GroupByResultsBlock;
+import org.apache.pinot.core.query.request.context.QueryContext;
+import org.apache.pinot.core.util.GroupByUtils;
+
+
+public class LinkedHashMapIndexedTable extends IndexedTable {
Review Comment:
(optional) Do you see value extending `IndexedTable`? Given the new
algorithm is very different from the existing one, will it have better
performance by making a completely new data structure?
##########
pinot-core/src/main/java/org/apache/pinot/core/query/request/context/QueryContext.java:
##########
@@ -541,6 +545,20 @@ public boolean isUnsafeTrim() {
return _isUnsafeTrim;
}
+ public boolean shouldSortAggregate() {
Review Comment:
Suggest moving this into `GroupByUtils` because it is specific to the
group-by combine algorithm. We should also pick a name more specific
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