We are search-as-a service offering which uses ElasticSearch(1.7) under the hood. One of our customer is complaining about the following error when using the 'suggest' end-point.
"ReduceSearchPhaseException[Failed to execute phase [fetch], [reduce] ]; nested: ElasticsearchIllegalStateException[Can't merge suggest result, this might be caused by suggest calls across multiple indices with different analysis chains. Suggest entries have different sizes actual  expected ]"
As per the error detail, the customer has more than one index with same field but different analyzer type. I'm trying to repro this, but creating 4 indexes with different analyzer type, but I'm unable to get a repro.
- When and why does this error occur?
- Should we restrict customers from creating indexes which have similar field name but different Analyzer, to prevent them from running into this error.
- What is the mitigation story? How can we enable the customer to access the suggest end-point successfully for their index?