Database Reference
In-Depth Information
The unsupported features in Impala
Let's take a look at what is not supported in Impala so you can make informed de-
cisions when choosing Impala as your distributed data-processing framework on Ha-
doop:
• Only HDFS is supported for data storage with Impala, and any other data stor-
age framework or RDBMS is not currently supported.
• Impala does not support dropping or deleting a row in a table. The alternative
is to either drop the table or migrate the required data to other tables and then
delete the entire original table.
• Transforms and window functions are not supported.
• Performing queries on streaming data is not supported.
• Hive UDF and Hive Index are not supported up to Impala 1.1.x; however, at
the time of writing this topic, Impala 1.2 Beta was available, which has support
for Scalar UDF and
user-defined aggregate
(
UDA
) functions.
• During query processing, unencrypted data is sometimes transmitted between
Impala daemons.
• At the time of writing this topic, Hadoop 2.0 achieved the GA milestone;
however, Hadoop-2.0-based YARN is not integrated with Impala.
• Custom Hive SerDes classes are not supported and only native file formats
are supported using the built-in SerDes.
Tip
Please visit this URL to learn about the new feature set available in Impala 1.2.x:
