Too many fields bad for elasticsearch index?
elasticsearch, lucene
Solution
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.
Problem
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", "key2":"someotherval", ... } ``` Is this a bad design pattern for elasticsearch index to have thousands of keys? Would each keys introduced this way create overhead for every documents under the index?