[英]How to unregister Spark UDF
我在Java中使用Spark 1.6.0。
我想注銷Spark UDF。 有沒有像刪除臨時表sqlContext.drop(TemporaryTableName)
?
sqlContext.udf().register("isNumeric", value -> {
if(StringUtils.isNumeric((String)value)) {
return 1;
} else {
return 0;
}
}, DataTypes.IntegerType);
sqlContext.functionRegistry().listFunction().toSet().toString()
我試圖從當前的sqlContext中獲取所有函數(包括我們定義的UDF),並且可以使用,但是有什么方法可以注銷自定義UDF'isNumeric'
通過執行以下SQL可以注銷udf。
spark.sql("drop temporary function isNumeric")
下面的代碼片段顯示了創建UDF和刪除UDF的過程。
scala> spark.udf.register("test", (value: String) => value.toInt)
res16: org.apache.spark.sql.expressions.UserDefinedFunction = UserDefinedFunction(<function1>,IntegerType,Some(List(StringType)))
scala> spark.catalog.listFunctions.filter(_.name == "test").collect
res17: Array[org.apache.spark.sql.catalog.Function] = Array(Function[name='test', className='null', isTemporary='true'])
scala> spark.sql("drop temporary function test")
res18: org.apache.spark.sql.DataFrame = []
scala> spark.catalog.listFunctions.filter(_.name == "test").collect
res19: Array[org.apache.spark.sql.catalog.Function] = Array()
Spark 1.6v :
scala> sqlContext.sql("drop temporary function test")
{"level": "INFO ", "timestamp": "2017-06-09 05:43:44,650", "classname": "hive.ql.parse.ParseDriver", "body": "Parsing command: drop temporary function test"}
{"level": "INFO ", "timestamp": "2017-06-09 05:43:44,650", "classname": "hive.ql.parse.ParseDriver", "body": "Parse Completed"}
{"level": "INFO ", "timestamp": "2017-06-09 05:43:44,655", "classname": "hive.ql.parse.ParseDriver", "body": "Parsing command: drop temporary function test"}
{"level": "INFO ", "timestamp": "2017-06-09 05:43:44,656", "classname": "hive.ql.parse.ParseDriver", "body": "Parse Completed"}
res7: org.apache.spark.sql.DataFrame = [result: string]
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