START

Overview

Starts another job pipeline immediately or with a slight delay. Unlike TRIGGER operations that starts other pipeline conditionally upon completion, the START operation can appear anywhere in the job pipeline. If the DELAY option is used, the operation is considered aynchronous and the execution of the current pipeline continues.

Syntax

Starts another pipeline unconditionally. This operation can be used anywhere in a pipeline.

START '...' 
    { SKIP_PREVIEW }
    { DELAY N }
;

DELAY	The number of seconds to wait at a minimum before starting the pipeline (0 = no delay)
SKIP_PREVIEW	Skip the start operation during preview operations

Example 1

-- Get data from two RSS Feeds and append their outputs
SELECT * FROM HTTP [Rss Feed] (GET /econi.xml);
APPEND SELECT * FROM HTTP [RSS Gov Feed] (GET /budget.xml);

-- Apply an ETL block 
APPLY PIPELINE (

  -- Start error processing if any errors were detected 
  -- DataColumn Expressions work using aggregate operations
  IF (MAX(statusCode) > 200)
  BEGIN
    PRINT 'At least one call failed' LEVEL 'warning';
  	START 'pipeline_notify_failure' ;
  END
  
  -- FILTER out errors, but exit if 0 records remain (break_on_empty)
  APPLY FILTER 'statusCode = 200';
  
  APPLY TX (//item) ON 'payload';

  START 'pipeline_notify_success' DELAY 5 SKIP_PREVIEW;

) BREAK_ON_EMPTY;