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https://issues.apache.org/jira/browse/HIVE-23030?focusedWorklogId=409384&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-409384
]
ASF GitHub Bot logged work on HIVE-23030:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 25/Mar/20 08:52
Start Date: 25/Mar/20 08:52
Worklog Time Spent: 10m
Work Description: kgyrtkirk commented on pull request #960: HIVE-23030 ds
rollup union
URL: https://github.com/apache/hive/pull/960#discussion_r397691314
##########
File path:
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/functions/HiveMergeablAggregate.java
##########
@@ -0,0 +1,66 @@
+/*
+ * 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.hadoop.hive.ql.optimizer.calcite.functions;
+
+import org.apache.calcite.sql.SqlAggFunction;
+import org.apache.calcite.sql.SqlFunctionCategory;
+import org.apache.calcite.sql.SqlKind;
+import org.apache.calcite.sql.type.SqlOperandTypeChecker;
+import org.apache.calcite.sql.type.SqlOperandTypeInference;
+import org.apache.calcite.sql.type.SqlReturnTypeInference;
+
+/**
+ * Mergeable aggregate.
+ *
+ * A mergeable aggregate is:
+ * - accepts the same kind as inputs as the output (an X^n -> X function)
+ *
+ * Example: the SUM function is a great example; since SUM of SUM -s is the
overall sum.
+ */
+public class HiveMergeablAggregate extends SqlAggFunction {
Review comment:
That interface is quite wide; we might be able to utilize it - but to do
that we should also implement functions like `singleton` (calculate the agg for
a single value) which is trivial for a `COUNT` or a `SUM` (the interface is
only implemented for things like these right now) ; but for a more complicated
thing - like a sketch function it should involve executing the actual function
to fold the single value.
I think it would be better to have a set of smaller interfaces - instead of
one bigger; that could make it easier to implement the most valuable ones for a
given usecase; when the others are not neccessarily needed.
This could be probably extended to support the `SqlSplittableAggFunction`
interface - but as you can see there will be some challenges along the way ; so
if we want to do that - I think it should at least have it's own ticket.
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Issue Time Tracking
-------------------
Worklog Id: (was: 409384)
Time Spent: 2h (was: 1h 50m)
> Enable sketch union-s to be rolled up
> -------------------------------------
>
> Key: HIVE-23030
> URL: https://issues.apache.org/jira/browse/HIVE-23030
> Project: Hive
> Issue Type: Sub-task
> Reporter: Zoltan Haindrich
> Assignee: Zoltan Haindrich
> Priority: Major
> Labels: pull-request-available
> Attachments: HIVE-23030.01.patch, HIVE-23030.02.patch
>
> Time Spent: 2h
> Remaining Estimate: 0h
>
> Enabling rolling up sketch aggregates could enable the matching of
> materialized views created for higher dimensions to be applied for lower
> dimension cases.
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