PostgreSQL 12 High Availability Cookbook - Third Edition

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The resulting graph isn't quite complete from our example. Note how the y axis simply says the units are in billions. Billions of what? We know the slot lag is represented in bytes, so we could edit the panel, enter the Visualization menu, and change the Unit to bytes. This makes the graph more representative of what's actually happening. As it turns out, the my_clone replica is really behind by about 2 GB of WAL data. Now we could add further advanced options such as setting alerts to avoid exhausting available storage space.

Don't forget to explore the Grafana documentation to really take advantage of its full range of capabilities. It's much easier to relate to metrics we can see and understand.