181 lines
5.4 KiB
Plaintext
181 lines
5.4 KiB
Plaintext
[[search-request-track-total-hits]]
|
|
=== Track total hits
|
|
|
|
Generally the total hit count can't be computed accurately without visiting all
|
|
matches, which is costly for queries that match lots of documents. The
|
|
`track_total_hits` parameter allows you to control how the total number of hits
|
|
should be tracked.
|
|
Given that it is often enough to have a lower bound of the number of hits,
|
|
such as "there are at least 10000 hits", the default is set to `10,000`.
|
|
This means that requests will count the total hit accurately up to `10,000` hits.
|
|
It's is a good trade off to speed up searches if you don't need the accurate number
|
|
of hits after a certain threshold.
|
|
|
|
When set to `true` the search response will always track the number of hits that
|
|
match the query accurately (e.g. `total.relation` will always be equal to `"eq"`
|
|
when `track_total_hits is set to true). Otherwise the `"total.relation"` returned
|
|
in the `"total"` object in the search response determines how the `"total.value"`
|
|
should be interpreted. A value of `"gte"` means that the `"total.value"` is a
|
|
lower bound of the total hits that match the query and a value of `"eq"` indicates
|
|
that `"total.value"` is the accurate count.
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
GET twitter/_search
|
|
{
|
|
"track_total_hits": true,
|
|
"query": {
|
|
"match" : {
|
|
"message" : "Elasticsearch"
|
|
}
|
|
}
|
|
}
|
|
--------------------------------------------------
|
|
// TEST[setup:twitter]
|
|
// CONSOLE
|
|
|
|
\... returns:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
{
|
|
"_shards": ...
|
|
"timed_out": false,
|
|
"took": 100,
|
|
"hits": {
|
|
"max_score": 1.0,
|
|
"total" : {
|
|
"value": 2048, <1>
|
|
"relation": "eq" <2>
|
|
},
|
|
"hits": ...
|
|
}
|
|
}
|
|
--------------------------------------------------
|
|
// TESTRESPONSE[s/"_shards": \.\.\./"_shards": "$body._shards",/]
|
|
// TESTRESPONSE[s/"took": 100/"took": $body.took/]
|
|
// TESTRESPONSE[s/"max_score": 1\.0/"max_score": $body.hits.max_score/]
|
|
// TESTRESPONSE[s/"value": 2048/"value": $body.hits.total.value/]
|
|
// TESTRESPONSE[s/"hits": \.\.\./"hits": "$body.hits.hits"/]
|
|
|
|
<1> The total number of hits that match the query.
|
|
<2> The count is accurate (e.g. `"eq"` means equals).
|
|
|
|
It is also possible to set `track_total_hits` to an integer.
|
|
For instance the following query will accurately track the total hit count that match
|
|
the query up to 100 documents:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
GET twitter/_search
|
|
{
|
|
"track_total_hits": 100,
|
|
"query": {
|
|
"match" : {
|
|
"message" : "Elasticsearch"
|
|
}
|
|
}
|
|
}
|
|
--------------------------------------------------
|
|
// CONSOLE
|
|
// TEST[continued]
|
|
|
|
The `hits.total.relation` in the response will indicate if the
|
|
value returned in `hits.total.value` is accurate (`"eq"`) or a lower
|
|
bound of the total (`"gte"`).
|
|
|
|
For instance the following response:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
{
|
|
"_shards": ...
|
|
"timed_out": false,
|
|
"took": 30,
|
|
"hits" : {
|
|
"max_score": 1.0,
|
|
"total" : {
|
|
"value": 42, <1>
|
|
"relation": "eq" <2>
|
|
},
|
|
"hits": ...
|
|
}
|
|
}
|
|
--------------------------------------------------
|
|
// TESTRESPONSE[s/"_shards": \.\.\./"_shards": "$body._shards",/]
|
|
// TESTRESPONSE[s/"took": 30/"took": $body.took/]
|
|
// TESTRESPONSE[s/"max_score": 1\.0/"max_score": $body.hits.max_score/]
|
|
// TESTRESPONSE[s/"value": 42/"value": $body.hits.total.value/]
|
|
// TESTRESPONSE[s/"hits": \.\.\./"hits": "$body.hits.hits"/]
|
|
|
|
<1> 42 documents match the query
|
|
<2> and the count is accurate (`"eq"`)
|
|
|
|
\... indicates that the number of hits returned in the `total`
|
|
is accurate.
|
|
|
|
If the total number of his that match the query is greater than the
|
|
value set in `track_total_hits`, the total hits in the response
|
|
will indicate that the returned value is a lower bound:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
{
|
|
"_shards": ...
|
|
"hits" : {
|
|
"max_score": 1.0,
|
|
"total" : {
|
|
"value": 100, <1>
|
|
"relation": "gte" <2>
|
|
},
|
|
"hits": ...
|
|
}
|
|
}
|
|
--------------------------------------------------
|
|
// TESTRESPONSE
|
|
// TEST[skip:response is already tested in the previous snippet]
|
|
|
|
<1> There are at least 100 documents that match the query
|
|
<2> This is a lower bound (`"gte"`).
|
|
|
|
If you don't need to track the total number of hits at all you can improve query
|
|
times by setting this option to `false`:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
GET twitter/_search
|
|
{
|
|
"track_total_hits": false,
|
|
"query": {
|
|
"match" : {
|
|
"message" : "Elasticsearch"
|
|
}
|
|
}
|
|
}
|
|
--------------------------------------------------
|
|
// CONSOLE
|
|
// TEST[continued]
|
|
|
|
\... returns:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
{
|
|
"_shards": ...
|
|
"timed_out": false,
|
|
"took": 10,
|
|
"hits" : { <1>
|
|
"max_score": 1.0,
|
|
"hits": ...
|
|
}
|
|
}
|
|
--------------------------------------------------
|
|
// TESTRESPONSE[s/"_shards": \.\.\./"_shards": "$body._shards",/]
|
|
// TESTRESPONSE[s/"took": 10/"took": $body.took/]
|
|
// TESTRESPONSE[s/"max_score": 1\.0/"max_score": $body.hits.max_score/]
|
|
// TESTRESPONSE[s/"hits": \.\.\./"hits": "$body.hits.hits"/]
|
|
|
|
<1> The total number of hits is unknown.
|
|
|
|
Finally you can force an accurate count by setting `"track_total_hits"`
|
|
to `true` in the request. |