Type of field for prefix search in Elastic Search - elasticsearch

I'm confused on what index type I should apply for my field for prefix search, many show search_as_you_type but I think auto complete is not what I'm going for.
I have a UUID field:
id: 34y72ca1-3739-41ff-bbec-f6d17479384c
The following terms should return the doc above:
3
34
34y72ca1
34y72ca1-3739
34y72ca1-3739-41ff-bbec-f6d17479384c
Using 3739 should not return it as it doesn't start with 3739. Initially this is what I was going for but then the wildcard field is not supported by Amazon AWS, so I compromise for prefix search instead of partial search.
I tried search_as_you_type field but it doesn't return the result when I use the whole ID. Actually, my use case is when user click enter, the results will be shown, instead of real-live when they type, so if speed is compromised its OK, just that I hope for something that will be good for many rows of data.
Thanks

If you have not explicitly defined any index mapping, then you need to use id.keyword field instead of the id field for the prefix query to show the appropriate results. This uses the keyword analyzer instead of the standard analyzer
{
"query": {
"prefix": {
"id.keyword": {
"value": "34y72ca1"
}
}
}
}
Otherwise, you can modify your index mapping, by adding multi fields for id field

Related

Terms query does not work on keyword field which contains an array of values

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:

Search inside _id field Elasticsearch

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

Elastic search wildcard search space issue

Consider index field "ProductName" having the value "dove 3.75oz" and when user searches for "dove 3.75oz" text below bool query is working fine to retreive the document:
{"bool":{"must":[{"wildcard":{"ProductName":{"value":"dove"}}},{"wildcard":{"ProductName":{"value":"3.75oz"}}}]}}
If user searches for "dove 3.75 oz" (Space between "3.75" and "oz") the bool query is failing to retrieve the same document:
{"bool":{"must":[{"wildcard":{"ProductName":{"value":"dove"}}},{"wildcard":{"ProductName":{"value":"3.75 oz"}}}]}}
Question: How to design a query using a wildcard query that supports space or no spaces? Please share an example.
Text fields values are broken into tokens by default and then stored. So something like "hello man"" will be saved separately as hello and man because of the space between them. And that is exactly why this will not work with a wildcard query.
{"wildcard":{"ProductName":{"value":"3.75 oz"}}}
It only works for single tokens. For wildcard queries you can use a special field type called wildcard.
If you do not want to reindex your data, try phrase search like:
"match_phrase": {
"ProductName": {
"query": "3.75 oz"
}
}

What is the difference between a field and a property in Elasticsearch?

I'm currently trying to understand the difference between fields (https://www.elastic.co/guide/en/elasticsearch/reference/current/multi-fields.html) and properties (https://www.elastic.co/guide/en/elasticsearch/reference/current/properties.html).
They are both somehow defined as a "subfield/subproperty" of a type/mapping property, both can have separate types and analyzers (as far as I understood it), both are accessed by the dot notation (mappingProperty.subField or mappingProperty.property).
The docs are using the terms "field" and "property" randomly, I have the feeling, for example:
Type mappings, object fields and nested fields contain sub-fields,
called properties.
What is the difference between properties and (sub-)fields? How do I decide if I have a property or a field?
In other words, how do I decide if I use
{
"mappings": {
"_doc": {
"properties": {
"myProperty": {
"properties": {
}
}
}
}
}
}
or
{
"mappings": {
"_doc": {
"properties": {
"myProperty": {
"fields": {
}
}
}
}
}
}
Subfields are indexed from the parent property source. While sub-properties need to have a "real" value in the document's source.
If your source contains a real object, you need to create properties. Each property will correspond to a different value from your source.
If you only want to index the same value but with different analyzers then use subfields.
It is often useful to index the same field in different ways for
different purposes. This is the purpose of multi-fields. For instance,
a string field could be mapped as a text field for full-text search,
and as a keyword field for sorting or aggregations:
(sorry I find its hard to explain =| )
Note: This is an explanation from my current understanding. It may not be 100% accurate.
A property is what we used to call field in a RDBMS (a standard relationship db like MySQL). It stores properties of an object and provides the high-level structure for an index (which we can compare to a table in a relational DB).
A field, which is linked (or included) into the property concept, is a way to index that property using a specific analyzer.
So lets say you have:
One analyzer (A) to uppercase
One analyzer (B) to lowercase
One analyzer (C) to translate to Spanish (this doesn't even exist, just to give you an idea)
What an analyzer does is transform the input (the text on a property) into a series of tokens that will be indexed. When you do a search the same analyzer is used so the text is transformed into those tokens, it gives each one a score and then those tokens are used to grab documents from the index.
(A) Dog = DOG
(B) Dog = dog
(C) Dog = perro
To search using a specific field configuration you call it using a dot:
The text field uses the standard analyzer.
The text.english field uses the English analyzer.
So the fields basically allow you to perform searches using different token generation models.

Group by field in found document

The best way to explain what I want to accomplish is by example.
Let us say that I have an object with fields name and color and transaction_id. I want to search for documents where name and color match the specified value and that I can accomplish easily with boolean queries.
But, I do not want only documents which were found with search query. I also want transaction to which those documents belong, and that is specified with transaction_id. For example, if a document has been found with transaction_idequal to 123, I want my query to return all documents with transaction_idequal to 123.
Of course, I can do that with two queries, first one to fetch all documents that match criteria, and the second one that will return all documents that have one of transaction_idvalues found in first query.
But is there any way to do it in a single query?
You can use parent-child relation ship between transaction and your object. Or nest the denormalize your data to include the objects in the transactions. Otherwise you'll have to do an application side join, meaning 2 queries.
Try an index mapping similar to the following, and include a parent_id in the objects.
{
"mappings": {
"transaction": {},
"object": {
"_parent": {
"type": "transaction"
}
}
}
}
Further reading:
https://www.elastic.co/guide/en/elasticsearch/guide/current/parent-child-mapping.html

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