As javanna mentioned in comments there's [_validate][1] api. Here's what works on my local elastic (version 1.6):
curl -XGET 'http://localhost:9201/pl/_validate/query?explain&pretty' -d'
{
"query": {
"query_string": {
"query": "a OR (b AND c) OR (d AND NOT(e or f))",
"default_field": "t"
}
}
}
'
`pl` is name of index on my cluster. Different index could have different analyzers, that's why query validation is executed in a scope of an index.
The result of the above curl is following:
{
"valid" : true,
"_shards" : {
"total" : 1,
"successful" : 1,
"failed" : 0
},
"explanations" : [ {
"index" : "pl",
"valid" : true,
"explanation" : "filtered(t:a (+t:b +t:c) (+t:d -(t:e t:or t:f)))->cache(org.elasticsearch.index.search.nested.NonNestedDocsFilter@ce2d82f1)"
} ]
}
I made one `OR` lowercase on purpose and as you can see in explanation, it is interpreted as a token and not as a operator.
As for interpretation of the explanation. Format is similar to `+-` [operators][2] of `query string` query:
- ( and ) characters start and end `bool query`
- \+ prefix means clause that will be in `must`
- \- prefix means clause that will be in `must_not`
- no prefix means that it will be in `should` (with `default_operator` equal to `OR`)
So above will be equivalent to following:
{
"bool" : {
"should" : [
{
"term" : { "t" : "a" }
},
{
"bool": {
"must": [
{
"term" : { "t" : "b" }
},
{
"term" : { "t" : "c" }
}
]
}
},
{
"bool": {
"must": {
"term" : { "t" : "d" }
},
"must_not": {
"bool": {
"should": [
{
"term" : { "t" : "e" }
},
{
"term" : { "t" : "or" }
},
{
"term" : { "t" : "f" }
}
]
}
}
}
}
]
}
}
I used `_validate` api quite heavily to debug complex `filtered` queries with many conditions. It is especially useful if you want to check how analyzer tokenized input like an url or if some filter is cached.
There's also an awesome parameter `rewrite` that I was not aware of until now, which causes the explanation to be even more detailed showing the actual Lucene query that will be executed.
[1]:
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]
