[role="xpack"]
[testenv="basic"]
[[indices-reload-analyzers]]
== Reload Search Analyzers

experimental[]

Reloads search analyzers and its resources.

Synonym filters (both `synonym` and `synonym_graph`) can be declared as
updateable if they are only used in <<search-analyzer,search analyzers>> 
with the `updateable` flag:

[source,console]
--------------------------------------------------
PUT /my_index
{
    "settings": {
        "index" : {
            "analysis" : {
                "analyzer" : {
                    "my_synonyms" : {
                        "tokenizer" : "whitespace",
                        "filter" : ["synonym"]
                    }
                },
                "filter" : {
                    "synonym" : {
                        "type" : "synonym",
                        "synonyms_path" : "analysis/synonym.txt",
                        "updateable" : true <1>
                    }
                }
            }
        }
    },
    "mappings": {
        "properties": {
            "text": {
                "type": "text",
                "analyzer" : "standard",
                "search_analyzer": "my_synonyms" <2>
            }
        }
    }
}
--------------------------------------------------

<1> Mark the synonym filter as updateable.
<2> Synonym analyzer is usable as a search_analyzer.

NOTE: Trying to use the above analyzer as an index analyzer will result in an error.

Using the <<indices-reload-analyzers,analyzer reload API>>, you can trigger reloading of the
synonym definition. The contents of the configured synonyms file will be reloaded and the
synonyms definition the filter uses will be updated. 

The `_reload_search_analyzers` API can be run on one or more indices and will trigger 
reloading of the synonyms from the configured file.

NOTE: Reloading will happen on every node the index has shards, so its important
to update the synonym file contents on every data node (even the ones that don't currently
hold shard copies; shards might be relocated there in the future) before calling
reload to ensure the new state of the file is reflected everywhere in the cluster.

[source,console]
--------------------------------------------------
POST /my_index/_reload_search_analyzers
--------------------------------------------------
// TEST[continued]

The reload request returns information about the nodes it was executed on and the
analyzers that were reloaded:

[source,console-result]
--------------------------------------------------
{
    "_shards" : {
        "total" : 2,
        "successful" : 2,
        "failed" : 0
    },
    "reload_details" : [
        {
            "index" : "my_index",
            "reloaded_analyzers" : [
                "my_synonyms" 
            ],
            "reloaded_node_ids" : [
                "mfdqTXn_T7SGr2Ho2KT8uw"
            ]
        }
    ]
}
--------------------------------------------------
// TEST[continued]
// TESTRESPONSE[s/"total" : 2/"total" : $body._shards.total/]
// TESTRESPONSE[s/"successful" : 2/"successful" : $body._shards.successful/]
// TESTRESPONSE[s/mfdqTXn_T7SGr2Ho2KT8uw/$body.reload_details.0.reloaded_node_ids.0/]

NOTE: Reloading does not happen on each shard of an index, but once on each node
the index has shards on. The total shard count can therefore differ from the number
of index shards.