Aggregation (HD)

Performs aggregate calculations on a data set by specifying a group-by configuration and an aggregate expression.

Information at a Glance

Parameter

 Description
Category Transform
Data source type HD
Send output to other operators Yes
Data processing tool Pig

Note: the Aggregation (HD) operator is for Hadoop data only. For database data, use the Aggregation (DB) operator.

Input

A data set from the preceding operator.

Bad or Missing Values

Null values are not allowed and result in an error.

Note:

Before using this operator, you can filter out null values or use the Null Value Replacement (HD) operator to replace them with a compatible value.

Configuration

Parameter Description
Notes Notes or helpful information about this operator's parameter settings. When you enter content in the Notes field, a yellow asterisk appears on the operator.
Aggregates Specify the Group By and Aggregators fields.

To display the Define Aggregations dialog, click Define Aggregates.

Store Results? Specifies whether to store the results.
  • true - results are stored.
  • false - the data set is passed to the next operator without storing.
Results Location The HDFS directory where the results of the operator are stored. This is the main directory, the subdirectory of which is specified in Results Name. Click Choose File to open the Hadoop File Explorer dialog and browse to the storage location. Do not edit the text directly.
Results Name The name of the file in which to store the results.
Overwrite Specifies whether to delete existing data at that path and file name.
  • Yes - if the path exists, delete that file and save the results.
  • No - Fail if the path already exists.
Storage Format Select the format in which to store the results. The storage format is determined by your type of operator.

Typical formats are Avro, CSV, TSV, or Parquet.

Compression Select the type of compression for the output.

Available Parquet compression options.

  • GZIP
  • Deflate
  • Snappy
  • no compression

Available Avro compression options.

  • Deflate
  • Snappy
  • no compression
Use Spark If Yes (the default), uses Spark to optimize calculation time.
Advanced Spark Settings Automatic Optimization
  • Yes specifies using the default Spark optimization settings.
  • No enables providing customized Spark optimization. Click Edit Settings to customize Spark optimization. See Advanced Settings dialog for more information.

Output

Visual Output
The data rows of the output table/view displayed (up to 2000 rows of the data).
Data Output
A new data set.