Elasticsearch query with grouping - elasticsearch

Question

I have database with products. Each Product is composed of fields: uuid, group_id, title, since, till.
since and till define interval of availability.
Intervals [since, till] are disjoint pairs for each group_id. So there are no 2 products within one group for which intervals intersect.
I need to fetch a list of products that meets the following conditions:
on the list should be at most 1 product from each group
each product matches the given title
each product is current (since <= NOW <= till) OR if current product does not exist within its group, it should be the nearest product from the future (min(since) such that since >= NOW)
ES mapping:
{
"products": {
"mappings": {
"dynamic": "false",
"properties": {
"group_id": {
"type": "long",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"title": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"since": {
"type": "date",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"till": {
"type": "date",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
}
}
}
}
Is it possible to create such query in Elasticsearch?

Answer 1

Looking at your mapping, I've created sample documents, the query and its response as below:
Sample Documents:
POST product_index/_doc/1
{
"group_id": 1,
"title": "nike",
"since": "2020-01-01",
"till": "2020-03-31"
}
POST product_index/_doc/2
{
"group_id": 2,
"title": "nike",
"since": "2020-01-01",
"till": "2020-03-31"
}
POST product_index/_doc/3
{
"group_id": 3,
"title": "nike",
"since": "2020-03-15",
"till": "2020-03-31"
}
POST product_index/_doc/4
{
"group_id": 3,
"title": "nike",
"since": "2020-03-19",
"till": "2020-03-31"
}
As mentioned above, there are like 4 documents in total, group 1 and 2 have one document each while group 3 has two documents with both since >= now
Query Request:
The summary of the query is below:
Bool
- Must
- Match title as nike
- Should
- clause 1 - since <= now <= till
- clause 2 - now <= since
Agg
- Terms on GroupId
- Top Hits (retrieve only 1st document as your clause is at most for each group, and sort them by asc order of since)
Below is the actual query:
POST product_index/_search
{
"size": 0,
"query": {
"bool": {
"must": [
{
"match": {
"title": "nike"
}
},
{
"bool": {
"should": [
{ <--- since <=now <= till
"bool": {
"must": [
{
"range": {
"till": {
"gte": "now"
}
}
},
{
"range": {
"since": {
"lte": "now"
}
}
}
]
}
},
{ <---- since >= now
"bool": {
"must": [
{
"range": {
"since": {
"gte": "now"
}
}
}
]
}
}
]
}
}
]
}
},
"aggs": {
"my_groups": {
"terms": {
"field": "group_id.keyword",
"size": 10
},
"aggs": {
"my_docs": {
"top_hits": {
"size": 1, <--- Note this to return at most one document
"sort": [
{ "since": { "order": "asc"} <--- Sort to return the lowest value of since
}
]
}
}
}
}
}
}
Notice that I've made use of Terms Aggregation and Top Hits as its sub-aggregation.
Response:
{
"took" : 7,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 4,
"relation" : "eq"
},
"max_score" : null,
"hits" : [ ]
},
"aggregations" : {
"my_groups" : {
"doc_count_error_upper_bound" : 0,
"sum_other_doc_count" : 0,
"buckets" : [
{
"key" : "3",
"doc_count" : 2,
"my_docs" : {
"hits" : {
"total" : {
"value" : 2,
"relation" : "eq"
},
"max_score" : null,
"hits" : [
{
"_index" : "product_index",
"_type" : "_doc",
"_id" : "3",
"_score" : null,
"_source" : {
"group_id" : 3,
"title" : "nike",
"since" : "2020-03-15",
"till" : "2020-03-31"
},
"sort" : [
1584230400000
]
}
]
}
}
},
{
"key" : "1",
"doc_count" : 1,
"my_docs" : {
"hits" : {
"total" : {
"value" : 1,
"relation" : "eq"
},
"max_score" : null,
"hits" : [
{
"_index" : "product_index",
"_type" : "_doc",
"_id" : "1",
"_score" : null,
"_source" : {
"group_id" : 1,
"title" : "nike",
"since" : "2020-01-01",
"till" : "2020-03-31"
},
"sort" : [
1577836800000
]
}
]
}
}
},
{
"key" : "2",
"doc_count" : 1,
"my_docs" : {
"hits" : {
"total" : {
"value" : 1,
"relation" : "eq"
},
"max_score" : null,
"hits" : [
{
"_index" : "product_index",
"_type" : "_doc",
"_id" : "2",
"_score" : null,
"_source" : {
"group_id" : 2,
"title" : "nike",
"since" : "2020-01-01",
"till" : "2020-03-31"
},
"sort" : [
1577836800000
]
}
]
}
}
}
]
}
}
}
Let me know if this helps!