Performance issues with larger amounts of data

Setup

Issue

This rather simple query displays an error:

Unstrip size limit exceeded (5,000,000)

{{#ask:[[Category:Correspondence]]
 |mainlabel=Institution
 |?Coordinates
 |?Author
 |?Language
 |format=map
 |limit=5000
}}

If I try to remove some printouts, to make it smaller, sometimes the message does not get displayed, but only a blank page is showing.

So the first improvement would be to fetch the problem to avoid the error and especially a blank page.

https://fina.knowledge.wiki/Test_Map

Performance

But the more general question is how to make maps that show several thousands of entries. With markerclusters, this is not a visulazation problem any more.

• Maybe with the deferred marker?
• Or with some kind of pre-clustering?
• Or with a better working ajax reload (see #649)

See also #565

Reproduce the query on the linked Test_Map page and observe the unstrip-size error or blank page with a limit of 5000. Read the deferred marker pull request and related issues #649 and #565 before defining a focused approach; done should include graceful handling of large result sets and a workable map display without the reported failure.