Join (HD)

Performs a table join on the input data sets by allowing users to define the input data set alias, the output columns, and the join condition.

Join operator

Information at a Glance

Category Transform
Data source type HD
Sends output to other operators Yes
Data processing tool Pig, MapReduce
Note: The Join (HD) operator is for Hadoop data only. For database data, use the Join (DB) operator.

Input

Accepts two data sets.

Configuration

Parameter Description
Notes Any notes or helpful information about this operator's parameter settings. When you enter content in the Notes field, a yellow asterisk is displayed on the operator.
Join Conditions Click Define Join Conditions to select the appropriate columns for joining the data and to specify the join type and output fields.

For more information, see Define Join Conditions Dialog Box (Hadoop).

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 Box 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 Box for more information.

Output

Visual Output
The resulting joined data rows of the output table or view are displayed in the Results window (up to 200 rows of the data):



Data Output

A data set of the output table or view of the joined data set.

Related reference