Elastic search recreating query in NEST not working - elasticsearch

Question

Im trying to recreate query in from Kibana dev into NEST but it's not giving me the same results.
The query I run in Kibana works perfectly returning 1 result
Here is my Kibana query:
GET /cats/_doc/_search
{
"query":{
"bool" : {
"minimum_should_match" :3,
"should": [
{"term" : { "name" : "cats" }},
{"term" : { "name" : "are" }},
{"term" : { "name" : "craze" }}
]
}
}
}
When I create the query in NEST it returns no results except when I change the minimum_should_match to 1 (it then returns 2 results )
Here is my NEST query:
string[] tmp = "Cats are craze".ToLower().Split(new string[] { " " }, StringSplitOptions.None);
var cats = ElasticMain.Search<dynamic>(s => s.From(from).Size(20).Query(
q => q.Bool(
b => b.MinimumShouldMatch(tmp.Length).Should(
l => l.Terms(
t => t.Name("name").Field("name").Terms(tmp)))
)));
What am I doing wrong?

Answer 1

You are not building the same query in NEST as you have in Kibana; the former is using a terms query, whilst the latter is using three term queries in a bool query should clause. The semantics of these two queries in combination with minimum should match is different.
The same query in NEST is
var client = new ElasticClient();
string[] tmp = "Cats are craze".ToLower().Split(new string[] { " " }, StringSplitOptions.None);
var from = 0;
var searchResponse = client.Search<dynamic>(s => s
.From(from)
.Size(20)
.Query(q => q
.Bool(b =>
{
b.MinimumShouldMatch(tmp.Length);
var shouldQueries =
new List<Func<QueryContainerDescriptor<dynamic>, QueryContainer>>(tmp.Length);
for (var i = 0; i < tmp.Length; i++)
{
var value = tmp[i];
shouldQueries.Add(qc => qc.Term(t => t
.Field("name")
.Value(value)
));
}
b.Should(shouldQueries);
return b;
})
)
);
which builds the following query
{
"from": 0,
"query": {
"bool": {
"minimum_should_match": 3,
"should": [
{
"term": {
"name": {
"value": "cats"
}
}
},
{
"term": {
"name": {
"value": "are"
}
}
},
{
"term": {
"name": {
"value": "craze"
}
}
}
]
}
},
"size": 20
}
When the number of should clauses that must match is equal to minimum_should_match as in this example, it's effectively the same as saying that they are all must clauses (without the minimum_should_match)
var client = new ElasticClient();
string[] tmp = "Cats are craze".ToLower().Split(new string[] { " " }, StringSplitOptions.None);
var from = 0;
var searchResponse = client.Search<dynamic>(s => s
.From(from)
.Size(20)
.Query(q =>
tmp.Aggregate((QueryContainer)null, (qc, v) => qc && q.Term("name", v))
)
);
which takes advantage of operator overloading on NEST queries to && them together, to build the query
{
"from": 0,
"query": {
"bool": {
"must": [
{
"term": {
"name": {
"value": "cats"
}
}
},
{
"term": {
"name": {
"value": "are"
}
}
},
{
"term": {
"name": {
"value": "craze"
}
}
}
]
}
},
"size": 20
}