Related: DARPA lets research contract for Gremlins program to launch overwhelming drone swarms DARPA researchers want to develop affordable UAVs that could be reused as many as 20 times for dangerous missions in contested air space like pre-attack reconnaissance and surveillance, as well as electronic attack to destroy or disable enemy communications, missile defenses, and battlefield networks.statement changes the structure or properties of an existing Impala table.For internal tables, this operation physically renames the directory within HDFS that contains the data files; the original directory name no longer exists.By qualifying the table names with database names, you can use this technique to move an internal table (and its associated data directory) from one database to another.See Using HDFS Caching with Impala (CDH 5.1 or higher only) for details about using the HDFS caching feature.
alter table d1.mobile rename to mobile; use d1; -- Move table from one database to another.
See Using Impala with the Amazon S3 Filesystem for details about reading and writing S3 data with Impala.
HDFS caching (CACHED IN clause): If you specify the clause, any existing or future data files in the table directory or the partition subdirectories are designated to be loaded into memory with the HDFS caching mechanism.
Cloudera recommends specifying a value greater than or equal to the HDFS block replication factor.
If you connect to different Impala nodes within an query option to make each DDL statement wait before returning, until the new or changed metadata has been received by all the Impala nodes. The following sections show examples of the use cases for various clause lets you change the name of an existing table, and optionally which database it is located in.create table change_to_csv (s1 string, s2 string) row format delimited fields terminated by '|'; -- Then we change it to a CSV table.