Fabric RTI 101: KQL Database OneLake Availability

I mentioned in a previous post that the standard storage format for Microsoft Fabric is in OneLake. In fact, you’ll find that pretty much everything that you use in Fabric ends up being stored in OneLake.

The thinking is that you’d be able to look at the data that was captured and being used by one tool then by using a different tool and so on. Now that that all makes sense, it’s not 100% true yet, but the story is getting better.

There are a few exceptions to that. So for example, there’s a Fabric SQL database, and that’s really just an Azure SQL database. It’s quite separate to the warehouse, which is a SQL warehouse, and the Fabric SQL database still has the same proprietary internal format that an Azure SQL database does.

But most things in Fabric end up being stored in one lake. So if you have a warehouse, which is a SQL warehouse, that also ends up in OneLake, as would a lakehouse.

KQL Database Storage

And it’s exactly the same for an eventhouse KQL database. I mentioned that an event house is a collection of KQL databases. Even though they are stored in OneLake, by default, they are not visible to OneLake. But you can change that.

If you open an Eventhouse and click on a KQL database that’s contained in it, on the right-hand side property pane, you’ll notice this:

When you slide that Disabled switch to Enabled, you’ll see this:

You get the option to make the tables available to OneLake, as well as within the KQL database. Note that you also get the option to apply that to existing tables. Alternately, it just applies to new tables.

And at that point, after a few seconds, the properties then show it’s visible.

Later, the number of tables that are available will also appear there. And in the case of the one that I’ve shown on the screen, there were no tables. But if there were tables, that would already have a count.

From that point on, it means that I could get to that data using other tools that can read from OneLake.
 

Learn more about Fabric RTI

If you really want to learn about RTI right now, we have an online on-demand course that you can enrol in, right now. You’ll find it at Mastering Microsoft Fabric Real-Time Intelligence

2026-03-10