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Task Lineage

In this tutorial we will show how to child and partent tasks so that once the parent run the child will follow. We call this task lineage.

For the official Snowflake documentation this tutorial was based on: https://docs.snowflake.com/en/user-guide/tasks-graphs#create-a-task-graph

Video

Video is still in development.

Requirement

This tutorial assumes you have nothing in your Snowflake account (Trial) and no complex security needs.

Setup

Lets start the setup prcoess in Snowflake.

If you don't have a database, schema or warehouse yet. 
use role sysadmin;

-- Create a database to store our schemas.
create database raw;

-- Create the schema. The schema stores all our objectss.
create schema raw.data;

/*
    Warehouses are synonymous with the idea of compute
    resources in other systems. We will use this
    warehouse to call our user defined function.
*/
create warehouse if not exists developer 
    warehouse_size = xsmall
    initially_suspended = true;

use database raw;
use schema data;
use warehouse developer;

First lets start by setting up the table we'll enter data into.

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create or replace table your_table (
    column1 string,
    column2 string
);

create or replace task parent_task
    warehouse = 'developer'
    schedule = 'USING CRON 0 0 * * * UTC' -- schedule to run daily at midnight
as
    insert into raw.data.your_table (column1, column2)
    values ('task', 'task');

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Task PARENT_TASK successfully created.

Parent Task

Next lets create a Snowflake notebook named "my_notebook" and enter the sql below. Add notebook

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insert into raw.data.your_table (column1, column2)
    values ('notebook', 'notebook')

Child Task

Lets create the child task and resume the task so it runs after our parent task.

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create or replace task child_task
    warehouse = 'developer'
    after parent_task
as
    execute notebook raw.data.my_notebook();

alter task child_task resume;

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Statement executed successfully.

You can also see the task linage by going to the parent task in the UI. Lineage

Run Task

Lets run the notebook and see that once the task row is added, the notebook row follows.

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-- Run the task tree.
execute task parent_task;

-- Look at the results.
select * from raw.aws.your_table;
# Column Column
1 task task
2 notebook notebook