12 Misconceptions about Virtual Warehouses in Snowflake

If you are new to Snowflake, you may often find the concept of a “virtual warehouse” a bit confusing. There is also confusion between changing a warehouse size or the number of clusters. Another category of errors relates to the goal of vertical versus horizontal scaling. Here is a collection of frequent honest mistakes most of us come up with during the learning process.

1. Virtual warehouses can be dynamically resized

Virtual warehouses can be only manually resized anytime, even when you may have running queries and other queries queued for them. You cannot auto-scale vertically (up or down) in Snowflake, only horizontally (in or out). And this last auto-scale mode is supported by a multi-cluster environment in the Enterprise Edition, in which every cluster is a virtual warehouse of the same size, processing queries in parallel, that can be started or stopped.

In the previous image, a size-4 (Medium) warehouse has been manually resized to a size-8 (Large). Warehouses can be resized between 1 (X-Small) and 512 (6X-Large), in powers of 2 (i.e. 1, 2, 4, 8, 16, 32, … 256, 512). The warehouse can be independent or part of a multi-cluster. Resizing a multi-cluster warehouse will increase or decrease with the same increment or decrement the size of any individual warehouse.