An index alias is a pointer to one or more indexes. A search operation executed against an alias is executed across all the indexes the alias points to. The coordinating node executes the request on all indices, collects the results, and sends them back to the client. The index operation, on the other hand, cannot be executed on an alias that points to more than one index. It is recommended to use an alias instead of the actual index name in your application. If the alias needs to point to a different index later, it would be an easy switch.
Due to how the data in stored in the inverted index, mappings of existing fields cannot be changed on the fly. For example, you want to treat a field that is previously indexed as string as ...
