Snowflake event based TASK Scheduling instead of Time Based task scheduling

Question

I'm in need of examples of Snowflake event based TASK Scheduling instead of Time Based task scheduling. I could not find those examples in snowflake document.

thanks in advance

Answer 1

The only event source that can trigger a task is the completion of a prior task in a task tree, see using the "AFTER" parameter.

CREATE TASK mytask2
  WAREHOUSE = mywh
  AFTER mytask1
AS
INSERT INTO mytable2(id,name) SELECT id, name FROM mytable1;

Also, if the event would be an insert or a change to a record in a table, you can create a stream on the table and use the WHEN clause to keep the scheduled task from running until the stream has data.

create stream mystream on table mytable
APPEND_ONLY = TRUE; // Set to true to only capture inserts

CREATE TASK mytask1
  WAREHOUSE = mywh
  SCHEDULE = '5 minute'
WHEN
  SYSTEM$STREAM_HAS_DATA('MYSTREAM')
AS
  INSERT INTO mytable1(id,name) SELECT id, name FROM mystream WHERE METADATA$ACTION = 'INSERT';

https://docs.snowflake.com/en/sql-reference/sql/create-task.html

https://docs.snowflake.com/en/sql-reference/sql/create-stream.html