Snowflake: What the clusterTags: snowflake
I recently attended a Snowflake 4 day partner bootcamp in Melbourne to get some hands on experience with Snowflake.
- Snowflake is a data warehouse built for the cloud that can handle structured and semi-structured data. Snowflake supports an unlimited number of simultaneous users so multiple groups of users can access data at the same time with no performance degradation.
- Snowflake is a zero-management data warehouse-as-a-service.
- Snowflake deals with all the parts of setting up a data warehouse solution so you don’t have to; you get to play with all the bells and whistles to tune Snowflake into your ideal data warehouse solution.
- Snowflake deals with all the management and setting up of your data warehouse so you can focus on the processes you care about.
- Snowflake comes with a fail safe which stores your historical data. This is non configurable and only accessible by contacting Snowflake support. Snowflake will take a copy of all your tables and views then store them for seven days and is only to be used to retrieve data in a case of damage or system failure. You get a seven day fail safe as default and this feature can’t be turned off.
- You can share your tables and materialized views with consumers who do not have a Snowflake account by using reader accounts.
One of the reoccurring themes was clusters. Snowflake uses the term cluster a lot!
This is how data is ordered and sorted in micro-partitions. Snowflake will cluster your data automatically into micro-partitions to allow for faster retrieval of frequently requested data. Micro-partitions is Snowflakes unique way of storing large amounts of data in a way that enables fast retrieval of frequently accessed data. Micro-partitions are immutable , compressed and encrypted at rest. You can evaluate how your table is clustered by looking at certain columns that your users will interface with.
A compute cluster is a collection of one or more VMs connected within a mesh. All virtual warehouses are an independent compute cluster which does not share its resources with other compute clusters. As each compute cluster does not share compute resources, all other virtual warehouses will have no impact on eachother. As a standard for your warehouse you will only have a single compute cluster meaning you are unable to scale out. If you need more than one compute cluster, you will need to utilise the multi cluster warehouses.
Used to help keep all frequently accessed data in the same micro-partition for faster retrieval. This is only ideal for very large tables as Snowflake automatically clusters your data into micro-partitions . Using cluster keys will override Snowflakes natural clustering. So say you want to find unicorns; you want to know how old they are, how big they are and where they were last spotted. This is the information you need to go forth and find unicorns so you want this information to be stored in the same micro-partition so you can get hold of this vital information fast. Cluster keys are used to keep frequently accessed data in the same micro-partition. So if I wanted to re cluster my UNICORNS table from above I could set clustering keys on AGE,SIZE and LOCATION.
ALTER TABLE UNICORNS CLUSTER BY (AGE,SIZE,LOCATION); ALTER TABLE UNICORNS RECLUSTER;
Multi Cluster Warehouses
Multi cluster warehouses can automatically scale out and spin up more compute clusters based on user concurrency needs. With multi cluster warehouses you can configure the minimum and maximum number of server clusters up to a maximum of ten. Snowflake documentation is really good and you can find out how much multi cluster warehouses will cost you in credits in different scenarios in the here. The two scaling strategies allow you to run using maximised clusters, when you start your warehouse it will automatically use all the clusters. Alternatively you can use the auto scaling strategy so that clusters will be started up only when they are needed. This means that you can set your warehouse scale to up to a maximum of eight clusters and a minimum of one so when it’s a busy period your warehouse will automatically start up the clusters it needs without you having to go in and manually start up more clusters. On the other side of that once traffic starts to slow down Snowflake will start to close the clusters it’s not using. This means you will only be paying for the resources you use.
Setting up your warehouse is as simple as:
CREATE OR REPLACE WAREHOUSE UNICORN_WH WAREHOUSE_SIZE = 'SMALL' AUTO_RESUME = TRUE MIN_CLUSTER_COUNT = 1 MAX_CLUSTER_COUNT = 5 INITIALLY_SUSPENDED = TRUE COMMENT = 'unicorn finder';
This being said ALWAYS remember to terminate your warehouses. While your warehouses are running they are costing you money.
alter warehouse UNICORN_WH suspend
Snowflake is a fast and powerful data warehousing solution with a lot of terminology to get your head around. Once you do you can start designing your own solution, do you need a single compute cluster or a multi cluster warehouse? Now that you know about all the different Snowflake clustering terms, you can start Snowflaking for yourself.Still not sure? We would be more than happy to help you.
Go forth and cluster.
If you think we can help you cluster unicorns in Snowflake, feel free to contact-us. While you are there you might want to check out our data platforms page located here.