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- geoSearch
geoSearch¶
-
geoSearch
¶ The
geoSearch
command provides an interface to MongoDB’s haystack index functionality. These indexes are useful for returning results based on location coordinates after collecting results based on some other query (i.e. a “haystack.”)The
geoSearch
command accepts a document that contains the following fields.Field Type Description geoSearch
string The collection to query. search
document Query to filter documents. near
array Coordinates of a point. maxDistance
number Optional. Maximum distance from the specified point. limit
number Optional. Maximum number of documents to return. readConcern
document Optional. Specifies the read concern. The default level is
"local"
.To use a read concern level of
"majority"
, you must use the WiredTiger storage engine and start themongod
instances with the--enableMajorityReadConcern
command line option (or thereplication.enableMajorityReadConcern
setting if using a configuration file).Only replica sets using
protocol version 1
support"majority"
read concern. Replica sets running protocol version 0 do not support"majority"
read concern.To ensure that a single thread can read its own writes, use
"majority"
read concern and"majority"
write concern against the primary of the replica set.New in version 3.2.
Behavior¶
Unless specified otherwise, the geoSearch
command
limits results to 50 documents.
Important
geoSearch
is not supported for sharded
clusters.
Examples¶
Consider the following example:
The above command returns all documents with a type
of
restaurant
having a maximum distance of 6 units from the
coordinates [ -73.9667, 40.78 ]
in the collection places
up to a
maximum of 30 results.
Override Default Read Concern¶
To override the default read concern level of "local"
,
use the readConcern
option.
The following operation on a replica set specifies a
Read Concern of "majority"
to read the
most recent copy of the data confirmed as having been written to a
majority of the nodes.
Note
To use a read concern level of
"majority"
, you must use the WiredTiger storage engine and start themongod
instances with the--enableMajorityReadConcern
command line option (or thereplication.enableMajorityReadConcern
setting if using a configuration file).Only replica sets using
protocol version 1
support"majority"
read concern. Replica sets running protocol version 0 do not support"majority"
read concern.Regardless of the read concern level, the most recent data on a node may not reflect the most recent version of the data in the system.
To ensure that a single thread can read its own writes, use
"majority"
read concern and "majority"
write concern against the primary of the replica set.