Getting started with data warehouses: Everything you need to know

With data being one of the most vital assets for an organization, managing and utilizing effectively is critical. But how do you make the best use of data? Identifying the most relevant and accurate data to enable improved decision-making is possible with data warehouses

These are big data repositories offering a consistent quality of data. If you are looking for ideas and the best ways to get started, here are some helpful tips. This article helps you get started with data warehouses and leverage them effectively for your business. 

What is a warehouse?

The warehouse is a cluster of computer resources used for processing DML operations. In Snowflake, you can use it for data loading. A warehouse has many properties like its size to help control and automate warehouse activity. It is also beneficial for query processing. A virtual warehouse is also called a “warehouse.”

A warehouse provides required resources like CPU, memory, and temporary storage for performing operations like executing SQL select statements that need compute resources, DML operations (insert, update, delete), loading and unloading data in tables. A warehouse must be running for sessions to perform these operations. While a warehouse is running, it consumes snowflake credits.

The warehouse can be resized at any time, like while running, to complete the need for more or less computing resources based on the operations performed by the warehouse. The size of a warehouse specifies compute resources available in the warehouse. Snowflake supports different warehouse sizes. The size of a warehouse impacts credit usage and billing in snowflake.

Increasing the warehouse size does not improve data loading performance always. It depends on the number of files loaded. The size of the warehouse is useful in query processing. It impacts the time required for executing large and complex queries.

Working with warehouses

You can perform all tasks using the snowflake web user interface or DDL commands. Credits get charged on the warehouse size, the number of warehouses, and the time each warehouse is running. For query processing, compute resources are required. It depends on the size and complexity of the query.

The running state warehouse maintains a cache of table data for queries processed by the warehouse. It improves the performance of the warehouse while running subsequent queries. The cache size gets decided by the compute resources in the warehouse. When the warehouse gets suspended, the cache drops. If the warehouse is resumed, the cache gets rebuilt. Furthermore, the queries can access the cache.

Creating a warehouse

Create a new warehouse in the system.

You can create a warehouse using a web user interface or SQL command. On the web user interface, click the warehouse’s tab and create. After that, you can select attributes for the warehouse according to your choice.

In SQL, execute the create warehouse command. For e.g., create a warehouse <warehouse_name>. Once the warehouse gets made, you can specify the warehouse initially in the “started” or “suspended” state.

Starting or resuming a warehouse

A warehouse can be started at any time, also at the time of the initial creation of the warehouse. After creating a warehouse, you can resume it at any time.

In the web user interface, click on the warehouses tab-> then click on <suspended_warehouse_name> -> click on resume.

In SQL, execute the alter warehouse command with the resume keyword. For e.g., alter warehouse <warehouse_name> resume.

Suspending a warehouse

A running or started warehouse can get suspended at any time. After suspending a warehouse, you can resume it at any time.

In the web, user interface click on the warehouses tab-> then click on <suspended_warehouse_name> -> click on resume.

In SQL, execute the alter warehouse command with the resume keyword. For e.g., alter warehouse <warehouse_name> resume.

Resizing a warehouse

A warehouse size can be changed while it is running and processing statements. You can resize up or down at any time.

In the web user interface, click on the warehouses tab-> then click on <warehouse_name> -> click on Configure.

In SQL, execute the alter warehouse command with set warehouse size=……

Bottom line

A warehouse is used in Snowflake to execute a query or DML statements. It contains computing resources for that purpose. A warehouse impacts activities like query processing, data loading, credit usage, and billing. It is also applicable while creating attributes specified for warehouses. It has other features like resume or suspend. In history, you can see how warehouses process each query or statement.

If you are looking for Snowflake support, our experts at Omnepresent can help. Contact us today to know more details about our services.

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