What are Auto-Indexes
When a query or patch cannot be answered by an existing index, RavenDB creates an Auto-Index (Dynamic Index)
These indexes are dynamically maintained to change automatically in response to changing query demands.
After a certain amount of time that an index is not used (30 minutes by default), the index goes into an idle state
and deleted after a set time-period (72 hours by default).
To provide for fast queries, indexes process information in the background.
If they are processing large datasets, each index can be demanding on I/O resources.
Why disable Auto-Index in Studio queries or patches
Some people use the Studio for one-time, ad-hoc queries and don't want a new index to start using resources.
In a playground database, it may be worth keeping auto-indexing active, even for random queries, because you want to be able to experiment.
On the other hand, disabling it in production can prevent expensive indexes from being created and running in the background.