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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 the mongod instances with the --enableMajorityReadConcern command line option (or the replication.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:
{
geoSearch : "places",
near : [33, 33],
maxDistance : 6,
search : { type : "restaurant" },
limit : 30
}
The above command returns all documents with a type of restaurant having a maximum distance of 6 units from the coordinates [30,33] 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 the mongod instances with the --enableMajorityReadConcern command line option (or the replication.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.
db.runCommand(
{
geoSearch: "places",
near: [ -73.9667, 40.78 ],
search : { type : "restaurant" },
readConcern: { level: "majority" }
}
)
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.