Re-Indexing Elasticsearch index with Existing Data
Recently, I was required to modify my existing elasticsearch index’s field mapping. But the problem is, there is no way to make a change in your existing field-mapping without creating a new index. But if I delete the existing index, all my data will be gone! So, what to do now??? Here comes a great solution! Recently elasticsearch has introduced a new API, RE_INDEX. Let’s see how can we use this to achieve our goal! Before that, I am gonna quote from the elasticsearch API: Reindex does not attempt to set up the destination index. It does not copy the settings of the source index. You should set up the destination index prior to running a _reindex action, including setting up mappings, shard counts, replicas, etc. So, let’s create a backup index : PUT project_copy { "settings" : { "index" : { "number_of_shards" : 5, "number_of_replicas" : 2 } } } Response: { "acknowledged" : true, &