elasticsearch Updating Index settings analyzer - elasticsearch

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