There are many articles talking about inverted index and posting list in elastic search. But I did not find any article which explain that how elastic search find document content by doc id.
Could anyone explain this to me?
thx.
Ragav is correct. However, I do have a bit to add that may help you work with document Ids.
When you index documents that don't have an ID, and ID is generated for you by ElasticSearch. That field name is "_id".
If you know the Id value of the document you wish to find, you can simply perform the query like this:
GET my_index/_search
{
"query": {
"terms": {
"_id": [ "1", "2" ]
}
}
}
https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-id-field.html
The above query would return documents that have have _id equal to 1 OR 2.
As Ragav said in his answer, if you created documents in the way described with id 1 or 2, you would return them with that sample query I pulled from the ElasticSearch documentation.
Hope this helps.
Elasticsearch is built on top of Lucene.
When you index a new document onto Elasticsearch, it indexes _index, _type and _id as a part of the document along with the actual content(_source).
So, when you try to get a document using the get API _index/_type/_id, it is basically converted into a query which searches for doc matching the _index, _type and the _id.
This is how Elasticsearch is able to return you the document.
Related
I am a beginner in Elasticsearch. I recently added a new field jc_job_meta_field which is of keyword type (see image 1 below as I output the mapping of all my fields) and my index is en-gb. I expect it to be an array to hold a bunch of values. And I now have a document with ["Virtual", "Hybrid"] in that field. I wanted to have the ability to search all entries with Virtual in the field jc_job_meta_field. But now when I do a term query search like this
{
"query": {
"terms": {
"jc_job_meta_field": ["Virtual"]
}
}
}
Nothing returned (see image 2 below). Shouldn't it at least return that exact document with [Virtual, Hybrid]? I checked a similar post here and it seems like I am doing exactly what's supposed to work. What went wrong here? Thanks in advance!
My Mapping and field values:
My query:
recently I made a change to the way ids were being generated in my ES index. Previously, we were generating the ids in the code, using a format like: uuid_WEEKDAY_COUNTRY_TIMESTAMP
I removed this and instead let the value of this field be auto-generated by ES (as i guess it should be)
How can i write a query that checks none of the old-format ids are still being generated? I tried something like
GET /_search
{
"query": {
"query_string": {
"query": "*WEDNESDAY*",
"default_field": "_id"
}
}
}
But got errors saying i can't query _id field, only text or keyword
how can i do this otherwise?
thanks
The _id field is special field handled in elastic search as the ID of the document. It is not indexed field like other text fields, though we can set the value , for documents where we do not specify this field it is actually "generated" based on the UID of the document (see: https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-id-field.html 2.8k).
The drop side of this is that , this field only supports a limited subset of the query functionality. One way to get over this is to add a field called id_field (as a text / keyword) into the document itself and then term queries on this field
I have an elastic index containing a dictionary in each document.
Docs:
{
"name" : "name1",
"paymentDict":
{
"card1": { "CardType": "Credit", "CardName": "Axis"},
"card2": { "CardType": "Debit", "CardName": "Axis"}
}
}
Dictionary Type: Dictionary<int,object>
I am expecting a good amount of write on this elastic index and want to test the performance aspect and didn't find anything useful in elastic docs explaining explicitly about the dictionary indexing. Need help in below query
How does indexing work for the dictionary?
Is this indexing will be the same as List<object>?
that would be an object in Elasticsearch - https://www.elastic.co/guide/en/elasticsearch/reference/7.14/object.html
you could also make this super simple and just have a document per card, that way you flatten things out
I am relatively new to this elastic search. So, I have an index called post which contain documents like this:
{
"id": 1,
"link": "https:www.instagram.com/p/XXXXX/",
"profile_id": 11,
"like_count": 100,
"comment_count": 12
}
I have another index called profile which contain documents like this:
{
"id": 11,
"username": "superman",
"name": "Superman",
"followers": 12312
}
So, as you guys can see, I have all profiles data under the index called profile and all posts data under the index called post. The "profile_id" present in the post document is linked with the "id" present in the profile document.
Is there any way, when I am querying the post index and filtering out the post documents the profile data will also appear along with the post document based on the "profile_id" present in the post document? Or somehow fetch the both data doing a multi-index search?
Thank you guys in advance, any help will be appreciated.
For the sake of performance, Elasticsearch encourages you to denormalize your data and model your documents accordingly to the responses you wish to get from your queries. However, in your case, I would suggest defining the relation post-profile by using a Join datatype (link to Elastic documentation) and using the parent-join queries to run your searches (link to Elastic documentation).
I have elastic search index with documents having a field "backend_name" like:- google, goolge_staging, google_stg1 etc.
I want only those documents that have "backend_name" = google
I am trying with the term query like this:
{ "query": { "term": { "backend_name": "google" } } }
But it returns me document having "backend_name" as goolge_staging, google_stg1 too. I want just document with "backend_name" = google.
One way to resolve it is to have goolge_staging, google_stg1 etc. in must not list but I want some better way. Suggestions?
It is provably because of the mapping you are using.
Take a look at the Elasticsearch documentation of term query
Try changing the mapping type to keyword so it matches only if it is an exact match.