Agent WranglersDEN-1Recommended
Keep analytics queries off the production database
Run reports, dashboards and analysis against a warehouse or a read replica, never against the primary database the app writes to.
How to do it
One heavy report can take the CPU, connections or locks the app needs. A small app can start with a read replica when its reports accept the lag, as Read from replicas only what may lag says. Move to a separate warehouse once reports join data from two or more systems. The app database stays the source of truth, as Name the source of truth says, and the warehouse is a copy. Give every reporting user a query time limit, as Set time limits on every query does.
How to check
The users on the primary database include no BI tool, notebook or analyst account. A listing of sessions on the primary over 7 days shows none from a reporting tool.
Sources
Related rules
- DAT-46 Read from replicas only what may lag in Data and databases
- DAT-44 Name the source of truth in Data and databases
- DAT-37 Set time limits on every query in Data and databases
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