WARNING: Version 1.4 of Elasticsearch has passed its EOL date.
This documentation is no longer being maintained and may be removed. If you are running this version, we strongly advise you to upgrade. For the latest information, see the current release documentation.
Sortedit
Allows to add one or more sort on specific fields. Each sort can be
reversed as well. The sort is defined on a per field level, with special
field name for _score
to sort by score.
{ "sort" : [ { "post_date" : {"order" : "asc"}}, "user", { "name" : "desc" }, { "age" : "desc" }, "_score" ], "query" : { "term" : { "user" : "kimchy" } } }
Sort Valuesedit
The sort values for each document returned are also returned as part of the response.
Sort Orderedit
The order
option can have the following values:
|
Sort in ascending order |
|
Sort in descending order |
The order defaults to desc
when sorting on the _score
, and defaults
to asc
when sorting on anything else.
Sort mode optionedit
Elasticsearch supports sorting by array or multi-valued fields. The mode
option
controls what array value is picked for sorting the document it belongs
to. The mode
option can have the following values:
|
Pick the lowest value. |
|
Pick the highest value. |
|
Use the sum of all values as sort value. Only applicable for number based array fields. |
|
Use the average of all values as sort value. Only applicable for number based array fields. |
Sort mode example usageedit
In the example below the field price has multiple prices per document. In this case the result hits will be sort by price ascending based on the average price per document.
curl -XPOST 'localhost:9200/_search' -d '{ "query" : { ... }, "sort" : [ {"price" : {"order" : "asc", "mode" : "avg"}} ] }'
Sorting within nested objects.edit
Elasticsearch also supports sorting by fields that are inside one or more nested objects. The sorting by nested field support has the following parameters on top of the already existing sort options:
-
nested_path
- Defines the on what nested object to sort. The actual sort field must be a direct field inside this nested object. The default is to use the most immediate inherited nested object from the sort field.
-
nested_filter
-
A filter the inner objects inside the nested path
should match with in order for its field values to be taken into account
by sorting. Common case is to repeat the query / filter inside the
nested filter or query. By default no
nested_filter
is active.
Nested sorting exampleedit
In the below example offer
is a field of type nested
. Because
offer
is the closest inherited nested field, it is picked as
nested_path
. Only the inner objects that have color blue will
participate in sorting.
curl -XPOST 'localhost:9200/_search' -d '{ "query" : { ... }, "sort" : [ { "offer.price" : { "mode" : "avg", "order" : "asc", "nested_filter" : { "term" : { "offer.color" : "blue" } } } } ] }'
Nested sorting is also supported when sorting by scripts and sorting by geo distance.
Missing Valuesedit
The missing
parameter specifies how docs which are missing
the field should be treated: The missing
value can be
set to _last
, _first
, or a custom value (that
will be used for missing docs as the sort value). For example:
{ "sort" : [ { "price" : {"missing" : "_last"} }, ], "query" : { "term" : { "user" : "kimchy" } } }
If a nested inner object doesn’t match with
the nested_filter
then a missing value is used.
Ignoring Unmapped Fieldsedit
[1.4.0.Beta1]
Added in 1.4.0.Beta1.
Before 1.4.0 there was the ignore_unmapped
boolean
parameter, which was not enough information to decide on the sort
values to emit, and didn’t work for cross-index search. It is still
supported but users are encouraged to migrate to the new
unmapped_type
instead.
By default, the search request will fail if there is no mapping
associated with a field. The unmapped_type
option allows to ignore
fields that have no mapping and not sort by them. The value of this
parameter is used to determine what sort values to emit. Here is an
example of how it can be used:
{ "sort" : [ { "price" : {"unmapped_type" : "long"} }, ], "query" : { "term" : { "user" : "kimchy" } } }
If any of the indices that are queried doesn’t have a mapping for price
then Elasticsearch will handle it as if there was a mapping of type
long
, with all documents in this index having no value for this field.
Geo Distance Sortingedit
Allow to sort by _geo_distance
. Here is an example:
{ "sort" : [ { "_geo_distance" : { "pin.location" : [-70, 40], "order" : "asc", "unit" : "km", "mode" : "min", "distance_type" : "sloppy_arc" } } ], "query" : { "term" : { "user" : "kimchy" } } }
-
distance_type
-
How to compute the distance. Can either be
sloppy_arc
(default),arc
(slighly more precise but significantly slower) orplane
(faster, but inaccurate on long distances and close to the poles).
Note: the geo distance sorting supports sort_mode
options: min
,
max
and avg
.
The following formats are supported in providing the coordinates:
Lat Lon as Propertiesedit
{ "sort" : [ { "_geo_distance" : { "pin.location" : { "lat" : 40, "lon" : -70 }, "order" : "asc", "unit" : "km" } } ], "query" : { "term" : { "user" : "kimchy" } } }
Lat Lon as Stringedit
Format in lat,lon
.
{ "sort" : [ { "_geo_distance" : { "pin.location" : "-70,40", "order" : "asc", "unit" : "km" } } ], "query" : { "term" : { "user" : "kimchy" } } }
Geohashedit
{ "sort" : [ { "_geo_distance" : { "pin.location" : "drm3btev3e86", "order" : "asc", "unit" : "km" } } ], "query" : { "term" : { "user" : "kimchy" } } }
Multiple reference pointsedit
Added in 1.4.0.Beta1.
Multiple geo points can be passed as an array containing any geo_point
format, for example
"pin.location" : [[-70, 40], [-71, 42]] "pin.location" : [{"lat": -70, "lon": 40}, {"lat": -71, "lon": 42}]
and so forth.
The final distance for a document will then be min
/max
/avg
(defined via mode
) distance of all points contained in the document to all points given in the sort request.
Script Based Sortingedit
Allow to sort based on custom scripts, here is an example:
{ "query" : { .... }, "sort" : { "_script" : { "script" : "doc['field_name'].value * factor", "type" : "number", "params" : { "factor" : 1.1 }, "order" : "asc" } } }
Note, it is recommended, for single custom based script based sorting,
to use function_score
query instead as sorting based on score is faster.
Track Scoresedit
When sorting on a field, scores are not computed. By setting
track_scores
to true, scores will still be computed and tracked.
{ "track_scores": true, "sort" : [ { "post_date" : {"reverse" : true} }, { "name" : "desc" }, { "age" : "desc" } ], "query" : { "term" : { "user" : "kimchy" } } }
Memory Considerationsedit
When sorting, the relevant sorted field values are loaded into memory.
This means that per shard, there should be enough memory to contain
them. For string based types, the field sorted on should not be analyzed
/ tokenized. For numeric types, if possible, it is recommended to
explicitly set the type to six_hun types (like short
, integer
and
float
).