The Impala drop table statement is used to delete an existing table in Impala. The data warehouse is located at /hive/warehouse/ on the default storage for the cluster. APPLIES TO: SQL Server 2016 (or higher) Use an external table with an external data source for PolyBase queries. This is a alternative that … Hive internal tables vs external tables. When dropping an internal table from Impala, the table’s data is dropped in Kudu; in contrast when dropping an external table, the table’s data is not dropped in Kudu. 1. you can go ahead create external table directly to impala , i dont see any issue in there . There are two types of tables that you can create with Hive: Internal: Data is stored in the Hive data warehouse. In Impala 1.4.0 and higher, you can derive column definitions from a raw Parquet data file, even without an existing Impala table. This example creates an external table mapped to the HBase table, usable by both Impala and Hive. 2. It is defined as an external table so that when dropped by Impala or Hive, the original HBase table is not touched at all. For example, you can create an external table pointing to an HDFS directory, and base the column definitions on one of the files in that directory: NOTE − You have to be careful while using this command because once a table is deleted, then all the information available in the table would also be lost forever.. Syntax. For details about internal and external tables, see Overview of Impala Tables. External Managed Table. This command creates an external table for PolyBase to access data stored in a Hadoop cluster or Azure blob storage PolyBase external table that references data stored in a Hadoop cluster or Azure blob storage. Use internal tables when one of the following conditions apply: Data is temporary. Use external table when multiple client tool want to have a centeralized data i, you have to decided whether your external table data is going to be used by another external program outside hdfs for example pig etc An external table is something totally different. You need to use EXTERNAL to create an externally managed table. Hive has a relational database on the master node it uses to keep track of state. If you specify the EXTERNAL clause, Impala treats the table as an "external" table, where the data files are typically produced outside Impala and queried from their original locations in HDFS, and Impala leaves the data files in place when you drop the table. For instance, if all your Kudu tables are in Impala in the database impala_kudu, use -d impala_kudu to use this database. Benefits of partitioning include improved query performance. Following is the syntax of the DROP TABLE Statement. In general, whenever we create a table inside a database in the Hive by default it is an Internal table also called the managed table. Internal Table. An external TABLE is a table that when DROPPED will NOT remove the physical data. This statement also deletes the underlying HDFS files for internal tables. By default tables are internal or managed, in which data also gets deleted when the table is removed from the internal location. When creating a new Kudu table using Impala, you can create the table as an internal table or an external table. Dropping the external table removes only its metadata and not the data. To quit the Impala Shell, use the following command: quit; Internal and External Impala Tables. For example, External tables are preferred over internal tables when we want to use the data shared with other tools on Hadoop like apache pig. An external table definition can include multiple partition columns, which impose a multi-dimensional structure on the external data.