Too many fields bad for elasticsearch index?

Question

Let say I have a thousand keys, and I would want to store the associated values. The intuitive approach seems to be something like

{
   \"key1\":\"someval\",         


        

Answer 1

If you know there is an upper limit to the number of keys you'll have, a few thousand fields is not a problem.

The problem is when you have an unbounded set of keys, e.g. when the key is derived from a value, as you'll have a continuously growing mapping and thus also cluster state. It can also lead to quirky searches.

This is a common enough question/issue that I dedicated a section to it in my article on Troubleshooting Elasticsearch searches, for Beginners.

In short, thousands of fields is no problem - not having control of the mapping is.