Track total hits
editTrack total hits
editGenerally 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.
GET twitter/_search { "track_total_hits": true, "query": { "match" : { "message" : "Elasticsearch" } } }
... returns:
{ "_shards": ... "timed_out": false, "took": 100, "hits": { "max_score": 1.0, "total" : { "value": 2048, "relation": "eq" }, "hits": ... } }
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:
GET twitter/_search { "track_total_hits": 100, "query": { "match" : { "message" : "Elasticsearch" } } }
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:
{ "_shards": ... "timed_out": false, "took": 30, "hits" : { "max_score": 1.0, "total" : { "value": 42, "relation": "eq" }, "hits": ... } }
... 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:
{ "_shards": ... "hits" : { "max_score": 1.0, "total" : { "value": 100, "relation": "gte" }, "hits": ... } }
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
:
GET twitter/_search { "track_total_hits": false, "query": { "match" : { "message" : "Elasticsearch" } } }
... returns:
Finally you can force an accurate count by setting "track_total_hits"
to true
in the request.