Elasticsearch - Update field of existing documents when changing mapping
I would like to add new field of type boolean to existing elastic mapping which can be described as follows:
{
"properties": {
"newBooleanField": {
"type": "boolean",
"null_value": true
}
}
}
After updating mapping I realised that existing documents doesn't have this field set to true. Only new documents created after changing mapping have these fields with default value true.
Is it possible to set default value to all existing documents when changing mapping without reindexing or manually change documents via script?
Related
How to create in the Kibana dev-tools a new Elasticsearch index and define one of its text field properties a not-analyzed ?
I know the command to create a new index is:
PUT /myNewIndexName
but I want one of the properties in the document to be not-analyzed
the analyzed value is from <7.X, the current approach to doing that is to use a keyword field - https://www.elastic.co/guide/en/elasticsearch/reference/7.15/keyword.html
PUT myNewIndexName
{
"mappings": {
"properties": {
"field_name": {
"type": "keyword"
}
}
}
}
My elasticsearch data has a large number of fields that I don't need to search by. But I would like to get aggregations like percentiles, median, count, avg. etc. on these fields.
Is there a way to disable searchability of a field but let it still be aggregatable?
Most of the fields are indexed by default and hence make them searchable. If you want to make a field non-searchable all you have to do is set its index param as false and doc_values to true.
As per elastic documentation:
All fields which support doc values have them enabled by default.
So you need not explicitly set "doc_values": true for such fields.
For e.g.
{
"mappings": {
"_doc": {
"properties": {
"only_agg": {
"type": "keyword",
"index": false
}
}
}
}
}
If you try to search on field only_agg in above example, elastic will throw exception with reason as below:
Cannot search on field [only_agg] since it is not indexed.
yeah take a look at doc_value:
https://www.elastic.co/guide/en/elasticsearch/reference/current/doc-values.html
I've already created an index, and it contains data from my MySQL database. I've got few fields which are string in my table, where I need them as different types (integer & double) in Elasticsearch.
So I'm aware that I could do it through mapping as follows:
{
"mappings": {
"my_type": {
"properties": {
"userid": {
"type": "text",
"fielddata": true
},
"responsecode": {
"type": "integer"
},
"chargeamount": {
"type": "double"
}
}
}
}
}
But I've tried this when I'm creating the index as a new one. What I wanted to know is how can I update an existing field (ie: chargeamount in this scenario) using mapping as a PUT?
Is this possible? Any help could be appreciated.
Once a mapping type has been created, you're very constrained on what you can update. According to the official documentation, the only changes you can make to an existing mapping after it's been created are the following, but changing a field's type is not one of them:
In general, the mapping for existing fields cannot be updated. There
are some exceptions to this rule. For instance:
new properties can be added to Object datatype fields.
new multi-fields can be added to existing fields.
doc_values can be disabled, but not enabled.
the ignore_above parameter can be updated.
I have mappings created wrongly for an object in elastic search. Is there a way to update the mappings. The mapping has been created wrongly for type of the object(String instead of double).
In general, the mapping for existing fields cannot be updated. There are some exceptions to this rule. For instance:
new properties can be added to Object datatype fields.
new multi-fields can be added to existing fields.
doc_values can be disabled, but not enabled.
the ignore_above parameter can be updated.
Source : https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-put-mapping.html
That's entirely possible, by PUTting the new mapping over the existing one, here are some examples.
Please note, that you will probably need to reindex all your data after you have done this, because I don't think that ES can convert string indexes to double indexes. (what will instead happen is, that you won't find any document when you search in that field)
PUT Mapping API allows you to add/modified datatype in an existing index.
PUT /assets/asset/_mapping
{
"properties": {
"common_attributes.asset_id": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"doc_values": true,
"normalizer": "lowercase_normalizer"
}
}
},
}
}
After updating the mapping, update the existing documents using bulk Update API.
POST /_bulk
{"update":{"_id":"59519","_type":"asset","_index":"assets"}}
{"doc":{"facility_id":491},"detect_noop":false}
Note - Use 'detect_noop' for detecting noop update.
If I change the mapping so certain properties have new/different boost values, does that work even if the documents have already been indexed? Or do the boost values get applied when the document is indexed?
You cannot change field level boost factors after indexing data. It's not even possible for new data to be indexed once the same fields have been indexed already for previous data.
The only way to change the boost factor is to reindex your data. The pattern to do this without changing the code of your application is to use aliases. An alias points to a specific index. In case you want to change the index, you create a new index, then reindex data from the old index to the new index and finally you change the alias to point to the new index. Reindexing data is either supported by the elasticsearch library or can be achieved with a scan/scroll.
First version of mapping
Index: items_v1
Alias: items -> items_v1
Change necessary, sencond version of the index with new field level boost values :
Create new index: items_v2
Reindex data: items_v1 => items_v2
Change alias: items -> items_v2
This might be useful in other situations where you want to change your mapping.
Field level boosts are, however, not recommended. The better approach is to use boosting at query time.
Alias commands are:
Adding an alias
POST /_aliases
{
"actions": [
{ "add": {
"alias": "tems",
"index": "items_v1"
}}
]
}
Removing an alias
POST /_aliases
{
"actions": [
{ "remove": {
"alias": "tems",
"index": "items_v1"
}}
]
}
They do not.
Index time boosting is generally not recommended. Instead, you should do your boosting when you search.