[CARBONDATA-2839] Add custom compaction example
[CARBONDATA-2839] Add custom compaction example
This closes #2620
diff --git a/examples/spark2/src/main/scala/org/apache/carbondata/examples/CustomCompactionExample.scala b/examples/spark2/src/main/scala/org/apache/carbondata/examples/CustomCompactionExample.scala
new file mode 100644
index 0000000..fcd5949
--- /dev/null
+++ b/examples/spark2/src/main/scala/org/apache/carbondata/examples/CustomCompactionExample.scala
@@ -0,0 +1,100 @@
+/*
+ * 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.carbondata.examples
+
+import java.io.File
+
+import org.apache.spark.sql.SparkSession
+
+import org.apache.carbondata.core.constants.CarbonCommonConstants
+import org.apache.carbondata.core.util.CarbonProperties
+import org.apache.carbondata.examples.util.ExampleUtils
+
+
+/**
+ * This example is for showing how to use custom compaction to merge specified segments.
+ */
+
+object CustomCompactionExample {
+
+ def main(args: Array[String]): Unit = {
+ val spark = ExampleUtils.createCarbonSession("CustomCompactionExample")
+ exampleBody(spark)
+ spark.close()
+ }
+
+ def exampleBody(spark : SparkSession): Unit = {
+ CarbonProperties.getInstance()
+ .addProperty(CarbonCommonConstants.CARBON_DATE_FORMAT, "yyyy/MM/dd")
+
+ spark.sql("DROP TABLE IF EXISTS custom_compaction_table")
+
+ spark.sql(
+ s"""
+ | CREATE TABLE IF NOT EXISTS custom_compaction_table(
+ | ID Int,
+ | date Date,
+ | country String,
+ | name String,
+ | phonetype String,
+ | serialname String,
+ | salary Int,
+ | floatField float
+ | ) STORED BY 'carbondata'
+ """.stripMargin)
+
+ val rootPath = new File(this.getClass.getResource("/").getPath
+ + "../../../..").getCanonicalPath
+ val path = s"$rootPath/examples/spark2/src/main/resources/dataSample.csv"
+
+ // load 4 segments
+ // scalastyle:off
+ (1 to 4).foreach(_ => spark.sql(
+ s"""
+ | LOAD DATA LOCAL INPATH '$path'
+ | INTO TABLE custom_compaction_table
+ | OPTIONS('HEADER'='true')
+ """.stripMargin))
+ // scalastyle:on
+
+ // show all segment ids: 0,1,2,3
+ spark.sql("SHOW SEGMENTS FOR TABLE custom_compaction_table").show()
+
+ // query data
+ spark.sql("SELECT count(*) FROM custom_compaction_table").show()
+ spark.sql("SELECT * FROM custom_compaction_table WHERE ID=5").show()
+
+ // do custom compaction, segments specified will be merged
+ spark.sql("ALTER TABLE custom_compaction_table COMPACT 'CUSTOM' WHERE SEGMENT.ID IN (1,2)")
+
+ // show all segment ids after custom compaction
+ spark.sql("SHOW SEGMENTS FOR TABLE custom_compaction_table").show()
+
+ // query data again, results should be same
+ spark.sql("SELECT count(*) FROM custom_compaction_table").show()
+ spark.sql("SELECT * FROM custom_compaction_table WHERE ID=5").show()
+
+ CarbonProperties.getInstance().addProperty(
+ CarbonCommonConstants.CARBON_DATE_FORMAT,
+ CarbonCommonConstants.CARBON_DATE_DEFAULT_FORMAT)
+
+ // Drop table
+ spark.sql("DROP TABLE IF EXISTS custom_compaction_table")
+ }
+
+}
