Load Data from Azure Blob Storage Using a Pipeline

Prerequisites

To complete this Quickstart, your environment must meet the following prerequisites:

• Azure Account: This Quickstart uses Azure Blob Store.

• SingleStore installation –or– a SingleStore cluster: You will connect to the database or cluster and create a pipeline to pull data from your Azure Blob Store.

Part 1: Creating an Azure Blob Container and Adding a File

1. On your local machine, create a text file with the following CSV contents and name it books.txt:

   Copy

   The Catcher in the Rye, J.D. Salinger, 1945
   Pride and Prejudice, Jane Austen, 1813
   Of Mice and Men, John Steinbeck, 1937
   Frankenstein, Mary Shelley, 1818

2. In Azure, create a container and upload books.txt to the container. For information on working with Azure, see the Azure Docs.

Once the books.txt file has been uploaded, you can proceed to the next part of the Quickstart.

Part 2: Creating a SingleStore Database and Azure Blob Pipeline

Now that you have an Azure container that contains an object (file), you can use SingleStore or DB to create a new pipeline and ingest the blobs.

We will create a new database and a table that adheres to the schema contained in books.txt file. At the MemSQL prompt, execute the following statements:

CREATE DATABASE books;

CREATE TABLE classic_books
(
title VARCHAR(255),
author VARCHAR(255),
date VARCHAR(255)
);

These statements create a new database named books and a new table named classic_books, which has three columns: title, author, and date.

Now that the destination database and table have been created, you can create an Azure pipeline. In Part 1 of this Quickstart, you uploaded the books.txt file to your container. To create the pipeline, you will need the following information:

• The name of the container, such as: my-container-name

• Your Azure Storage account’s name and key, such as:

  • Account Name: your_account_name

  • Account Key: your_account_key

Using these identifiers and keys, execute the following statement, replacing the placeholder values with your own:

CREATE PIPELINE library
AS LOAD DATA AZURE 'my-container-name'
CREDENTIALS '{"account_name": "your_account_name", "account_key":
"your_account_key"}'
INTO TABLE `classic_books`
FIELDS TERMINATED BY ',';

You can see what files the pipeline wants to load by running the following:

SELECT * FROM information_schema.PIPELINES_FILES;

If everything is properly configured, you should see one row in the Unloaded state, corresponding to books.txt. The CREATE PIPELINE statement creates a new pipeline named library, but the pipeline has not yet been started, and no data has been loaded. A SingleStore pipeline can run either in the background or be triggered by a foreground query. Start it in the foreground first.

START PIPELINE library FOREGROUND;

When this command returns successfully, all files from your bucket will be loaded. If you check information_schema.PIPELINES_FILES again, you should see all files in the Loaded state. Now query the classic_books table to make sure the data has actually loaded.

SELECT * FROM classic_books;

+------------------------+-----------------+-------+
| title                  | author          | date  |
+------------------------+-----------------+-------+
| The Catcher in the Rye |  J.D. Salinger  |  1945 |
| Pride and Prejudice    |  Jane Austen    |  1813 |
| Of Mice and Men        |  John Steinbeck |  1937 |
| Frankenstein           |  Mary Shelley   |  1818 |
+------------------------+-----------------+-------+

You can also have SingleStore run your pipeline in background. In such a configuration, SingleStore will periodically poll Azure Blob Storage for new files and continuously load them as they are added to the storage container. Before running your pipeline in the background, you must reset the state of the pipeline and the table.

DELETE FROM classic_books;
ALTER PIPELINE library SET OFFSETS EARLIEST;

The first command deletes all rows from the target table. The second causes the pipeline to start from the beginning, in this case, forgetting it already loaded books.txt so you can load it again. You can also drop and recreate the pipeline, if you prefer.

To start a pipeline in the background, run START PIPELINE.

START PIPELINE library;

This statement starts the pipeline. To see whether the pipeline is running, run SHOW PIPELINES.

SHOW PIPELINES;

+----------------------+---------+
| Pipelines_in_books   | State   |
+----------------------+---------+
| library              | Running |
+----------------------+---------+

At this point, the pipeline is running and the contents of the books.txt file should once again be present in the classic_books table.