WARNING: Version 0.90 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 mode optionedit
From version 0.90.0.Beta1
Elasticsearch supports sorting by array
fields which is also known as 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
Also from version 0.90.0.Beta1
Elasticsearch 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" } } } } ] }'
Since version 0.90.1
nested sorting is also support 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" } } }
Note: from version 0.90.1
if a nested inner object doesn’t match with
the nested_filter
then a missing value is used.
Ignoring Unmapped Fieldsedit
By default, the search request will fail if there is no mapping
associated with a field. The ignore_unmapped
option allows to ignore
fields that have no mapping and not sort by them. Here is an example of
how it can be used:
{ "sort" : [ { "price" : {"ignore_unmapped" : true} }, ], "query" : { "term" : { "user" : "kimchy" } } }
Geo Distance Sortingedit
Allow to sort by _geo_distance
. Here is an example:
{ "sort" : [ { "_geo_distance" : { "pin.location" : [-70, 40], "order" : "asc", "unit" : "km" } } ], "query" : { "term" : { "user" : "kimchy" } } }
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" } } }
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 custom_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
).