Performance problem of Data Visualizer in Discover for large index patterns

[timroes]

When the data visualizer is used in Discover and tried to be switched to on an index pattern with a lot of fields (tested with 30k) the whole browser freezes us for at least 10 seconds. I think we need to improve performance of the Data Visualizer before we can enable it on large index patters.

We have basically two options:

(1) Leave it as it is, i.e. since the advanced setting to turn it on is off by default, users will never run into that by default.
(2) Even when the flag is on, disable the button in Discover (with a hint) if the index pattern has above a specific amount of fields.

@qn895 Do you have any experience from prior performance testing, up to how many fields the Data Visualizer will still run smoothly?

[elasticmachine]

Pinging @elastic/kibana-data-discovery (Team:DataDiscovery)

[VijayDoshi]

Does this happen on load of Discover or when you switch to the Field Statistics view if the default Data View is the one with 30k fields?

[kertal]

Fixed by #124898