Preference
editPreference
editControls a preference
of the shard copies on which to execute the search. By
default, Elasticsearch selects from the available shard copies in an
unspecified order, taking the allocation awareness and
adaptive replica selection configuration into
account. However, it may sometimes be desirable to try and route certain
searches to certain sets of shard copies, for instance to make better use of
per-copy caches.
The preference
is a query string parameter which can be set to:
|
The operation will be executed only on shards allocated to the local node. |
|
The operation will be executed on shards allocated to the local node if possible, and will fall back to other shards if not. |
|
The operation will be executed on nodes with one of the provided node
ids ( |
|
Restricts the operation to the specified shards. ( |
|
Restricts the operation to nodes specified according to the node specification. If suitable shard copies exist on more than one of the selected nodes then the order of preference between these copies is unspecified. |
Custom (string) value |
Any value that does not start with |
For instance, use the user’s session ID xyzabc123
as follows:
GET /_search?preference=xyzabc123 { "query": { "match": { "title": "elasticsearch" } } }
The _only_local
preference guarantees only to use shard copies on the
local node, which is sometimes useful for troubleshooting. All other options do
not fully guarantee that any particular shard copies are used in a search,
and on a changing index this may mean that repeated searches may yield
different results if they are executed on different shard copies which are in
different refresh states.