elasticsearch Updating Index settings analyzer

Question

I have a Books Index which contains multiple subjects

chemistry

biology

etc
Each subject have there own set of synonyms and a global synonyms

PUT /books/_settings { "analysis": { "filter": { "biology_synonyms": { "type": "synonym", "synonyms": [ "a, aa, aaa" ] }, "chemistry_synonyms": { "type": "synonym", "synonyms": [ "c, cc, ccc" ] }, "global_synonyms": { "type": "synonym", "synonym": [ "x, xx, xxx" ] } }, "analyzer": { "chemistry_analyzer": { "filter": [ "global_synonyms", "chemistry_synonyms" ] }, "biology_analyzer": { "filter": [ "global_synonyms", "biology_synonyms" ] } } } }

Let's say at any point in time, I want to add new subject named "Astronomy"
Now the problem is how do I Update the index settings to add new "Astronomy_synonyms" and "Astronomy_analyzer"

my application requires me to append settings with existing filters and analyzers, I don't want to overwrite(replace settings)

Answer 1

You can definitely append new token filters and analyzers, however you need to close your index before updating the settings and reopen it when done. In what follows, I assume the index already exists.

Let's say you create your index with the following initial settings:

PUT /books
{
  "settings": {
    "analysis": {
      "filter": {
        "biology_synonyms": {
          "type": "synonym",
          "synonyms": [
            "a, aa, aaa"
          ]
        },
        "chemistry_synonyms": {
          "type": "synonym",
          "synonyms": [
            "c, cc, ccc"
          ]
        },
        "global_synonyms": {
          "type": "synonym",
          "synonyms": [
            "x, xx, xxx"
          ]
        }
      },
      "analyzer": {
        "chemistry_analyzer": {
          "type": "custom",
          "tokenizer": "standard",
          "filter": [
            "global_synonyms",
            "chemistry_synonyms"
          ]
        },
        "biology_analyzer": {
          "type": "custom",
          "tokenizer": "standard",
          "filter": [
            "global_synonyms",
            "biology_synonyms"
          ]
        }
      }
    }
  }
}

Then you need to close your index:

POST books/_close

Then you can append new analyzers and token filters:

PUT /books/_settings
{
  "analysis": {
    "filter": {
      "astronomy_synonyms": {
        "type": "synonym",
        "synonyms": [
          "x, xx, xxx"
        ]
      }
    },
    "analyzer": {
      "astronomy_analyzer": {
        "type": "custom",
        "tokenizer": "standard",
        "filter": [
          "global_synonyms",
          "astronomy_synonyms"
        ]
      }
    }
  }
}

And finally reopen your index

POST books/_open

If you then check your index settings, you'll see that everything has been properly merged.

Answer 2

You can only define new analyzers on closed indices. To add an analyzer, you must close the index, define the analyzer, and reopen the index.

POST /books/_close

PUT /books/_settings
{
    "analysis": {
        "filter": {
            "astronomy_synonyms": {
                "type": "synonym",
                "synonyms": [
                   "a, aa, aaa=>a"
                ]
            }
        },
        "analyzer": {
            "astronomy_analyzer": {
              "tokenizer" : "whitespace",
                "filter": [
                    "global_synonyms", "astronomy_synonyms"
                ]
            }
        }
    }
}

POST /books/_open