[GitHub] [incubator-pinot] cbalci commented on a change in pull request #6383: Introduce 'LOOKUP' Transform Function

[GitBox <gi...@apache.org>]

cbalci commented on a change in pull request #6383:
URL: https://github.com/apache/incubator-pinot/pull/6383#discussion_r549177848



##########
File path: pinot-core/src/main/java/org/apache/pinot/core/operator/transform/function/LookupTransformFunction.java
##########
@@ -0,0 +1,284 @@
+/**
+ * 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.operator.transform.function;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.ArrayList;
+import com.google.common.base.Preconditions;
+import org.apache.commons.lang3.ArrayUtils;
+import org.apache.pinot.core.common.DataSource;
+import org.apache.pinot.core.data.manager.offline.DimensionTableDataManager;
+import org.apache.pinot.core.operator.blocks.ProjectionBlock;
+import org.apache.pinot.core.operator.transform.TransformResultMetadata;
+import org.apache.pinot.spi.data.FieldSpec;
+import org.apache.pinot.spi.data.readers.GenericRow;
+import org.apache.pinot.spi.data.readers.PrimaryKey;
+
+/**
+ * LOOKUP function take 4 or more arguments:
+ * <ul>
+ *   <li><b>TableName:</b> name of the dimension table which will be used</li>
+ *   <li><b>ColumnName:</b> column name from the dimension table to look up</li>
+ *   <li><b>JoinKey:</b> primary key column name for the dimension table. Note: Only primary key[s] is supported for JoinKey</li>
+ *   <li><b>JoinValue:</b> primary key value</li>
+ *   ...<br>
+ *   *[If the dimension table has more then one primary keys (composite pk)]
+ *     <li><b>JoinKey2</b></li>
+ *     <li><b>JoinValue2</b></li>
+ *   ...
+ * </ul>
+ * <br>
+ * Example:
+ * <pre>{@code select playerName, teamID, lookup('baseballTeams', 'teamName', 'teamID', teamID) from baseballStats limit 10}</pre>
+ * <br>
+ * Above example joins the dimension table 'baseballTeams' into regular table 'baseballStats' on 'teamID' key.
+ * Lookup function returns the value of the column 'teamName'.
+ */
+public class LookupTransformFunction extends BaseTransformFunction {
+    public static final String FUNCTION_NAME = "lookUp";
+    private static final String TABLE_NAME_SUFFIX = "_OFFLINE";

Review comment:
       Hi Xiang, yes you're right. In current design Dimension Table has the following constraints:
   - Must be of OFFLINE type
   - Must have a primary key (we support lookups by primary key for now)
   - Must have ingestion type REFRESH
   
   Please check out #6286 and #6346 to see implementation details.




----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
users@infra.apache.org



---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscribe@pinot.apache.org
For additional commands, e-mail: commits-help@pinot.apache.org