1. Adding analyzer to existing index

• using settings api

PUT /analyzer_test/_settings
{
    "analysis" : {
        "analyzer" : {
            "my_second_analyzer" : {
                (... analyzer settings ...)
            }
        }
    }
}

• error will occur stating that non-dynamic settings for open indexes cannot be updated

1-1. open & close index

• open index : available for indexing and search requests
• close index : refuse requests

1-2. dynamic & static settings

• Dynamic settings : can be changed without closing the index

• Static settings : require index to be closed

• analysis settings are static settings, to change static settings,

  • first close index with close API
  • then change settings
  • reopen index with open API

POST /analyzer_test/_close

PUT /analyzer_test/_settings
{
    "analysis" : {
        "analyzer" : {
            "my_second_analyzer" : {
                (... analyzer settings ...)
            }
        }
    }
}

POST /analyzer_test/_open

1-3. static settings on production env

• for mission critical production systems
  • create new index with updated settings
  • use index alias for the transition

2. Updating analyzer in existing index

• to update analyzers, PUT request full settings with the same analyzer name
  • there will be conflict between docs index before the analyzer update and after
  • use update by query API to reindex

POST analyzer_test/_update_by_query?conflicts=proceed