I am getting the results based on various filters in the Elasticsearch which also includes pagination.
Now I need to navigate between previous and next record from that search results, when we open a record of the search results.
Is there a way to achieve this through Elasticsearch?
You could use the from and size parameters of the Search API.
GET /_search
{
"from" : 0, "size" : 10,
"query" : {
"term" : { "user" : "kimchy" }
}
}
or
GET /_search?from=0&size=10
{
"query" : {
"term" : { "user" : "kimchy" }
}
}
Note the default value for size is 10.
Related
On my eCommerce store I want to only include the first item in each group (grouped by item_id) in the final results. At the same time I don't want to lose my aggregations (little numbers next to attributes that indicate how many items with that attribute are found).
Here is a little example:
Suppose I make a search for items and only 25 show up. This is the result for the color aggregation that I currently get:
black (65)
green (32)
white (13)
And I want it to be:
black (14)
green (6)
white (5)
The numbers should amount to the total number the user actually sees on the page.
How could I achieve that with Elasticsearch? I have tried both Grouping (Top Hits) and Field Collapsing and both don't seem to fit my use case. Solr does it almost by default with its Grouping functionality.
It should be rather easy. When you are asking for aggregation you are simple sending request to the _search endpoint. Example:
POST /exams/_search
{
"aggs" : {
"avg_grade" : { "avg" : { "field" : "grade" } }
}
}
and in above example you will get aggregation for all the documents.
If you want to get aggregation for specific documents you just need to add specific query to the request body, like:
POST /exams/_search
{
"query": {
"bool" : {
"must" : {
"query_string" : {
"query" : "some query string here"
}
},
"filter" : {
"term" : { "user" : "kimchy" }
}
}
},
"aggs" : {
"avg_grade" : { "avg" : { "field" : "grade" } }
}
}
and you can send size and from parameters as well.
this example is from elastic search official docs
GET /_search
{
"size" : 10,
"query" : {
"term" : { "user" : "kimchy" }
}
}
which return 10 docs for user "kimchy".
I have 30 more such users, is there any way to extract 10 docs from each of the user in a request.
Currently I hit 30 queries separately and later join all of them.
If i understood your question correctly, You can use terms query for multiple users -
GET /_search
{
"size" : 10,
"query" : {
"terms" : { "user" : ["kimchy", "abc", "xyz"] }
}
}
Refer this for more details - Terms query
Say I have a filter in query like this:
{
"query" : {
"filtered" : {
"filter" : {
"term" : {
"price" : 20
}
}
}
}
}
According to the official doc, there will be a filter cache associated to the key "price".
One day, I change the query as follow:
{
"query" : {
"filtered" : {
"filter" : {
"term" : {
"price" : 20,
"_cache" : false
}
}
}
}
}
Will Elasticsearch automatically remove the exist cache?
Not really sure. It will probably be removed eventually but probably not immediately. It doesn't really matter however as setting _cache = false will tell elastic search to not use the cache even if it is technically still there. If you want to clear the cache manually there's an API for it.
Here is an example:curl -XPOST 'http://localhost:9200/twitter/_cache/clear
https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-clearcache.html
I am using terms aggregation on elasticsearch to get most used words in a index with 380607390 (380 millions) and i receive timeout on my application.
The aggregated field is a text with a simple analyzer( the field holds post content).
My question is:
The terms aggregation is the correct aggregation to do that? With a large content field?
{
"aggs" : {
"keywords" : {
"terms" : { "field" : "post_content" }
}
}
}
You can try this using min_doc_count. You would ofcourse not want to get those words which have been used just once or twice or thrice...
You can set min_doc_count as per your requirement. This would definitely
reduce the time.
{
"aggs" : {
"keywords" : {
"terms" : { "field" : "post_content",
"min_doc_count": 5 //----->Set it as per your need
}
}
}
}
Is there a way in Elasticsearch through filters, queries, aggregations etc to search for a list of document ids and have returned which ids did not hit?
With a small list it is easy enough to compare the results against the requested ids list but I'm dealing with lists of ids in the tens of thousands and it is not going to be performant to do that.
Do you mean, from https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-not-filter.html
"filtered" : {
"query" : {
"term" : { "name.first" : "shay" }
},
"filter" : {
"not" : {
"range" : {
"postDate" : {
"from" : "2010-03-01",
"to" : "2010-04-01"
}
}
}
}
}
Take a look at the guide at https://www.elastic.co/guide/en/elasticsearch/reference/current/index.html