elasticsearch/docs/reference/migration/migrate_5_0/rest.asciidoc

[[breaking_50_rest_api_changes]]
=== REST API changes

==== id values longer than 512 bytes are rejected

When specifying an `_id` value longer than 512 bytes, the request will be
rejected.

==== `/_optimize` endpoint removed

The deprecated `/_optimize` endpoint has been removed. The `/_forcemerge`
endpoint should be used in lieu of optimize.

The `GET` HTTP verb for `/_forcemerge` is no longer supported, please use the
`POST` HTTP verb.

==== Index creation endpoint only accepts `PUT`

It used to be possible to create an index by either calling `PUT index_name`
or `POST index_name`. Only the former is now supported.

==== `HEAD {index}/{type}` replaced with `HEAD {index}/_mapping/{type}`

The endpoint for checking whether a type exists has been changed from
`{index}/{type}` to `{index}/_mapping/{type}` in order to prepare for the
removal of types when `HEAD {index}/{id}` will be used to check whether a
document exists in an index. The old endpoint will keep working until 6.0.

==== Removed `mem` section from `/_cluster/stats` response

The `mem` section contained only the `total` value, which was actually the
memory available throughout all nodes in the cluster. The section contains now
`total`, `free`, `used`, `used_percent` and `free_percent`.

==== Revised node roles aggregate returned by `/_cluster/stats`

The `client`, `master_only`, `data_only` and `master_data` fields have been
removed in favor of `master`, `data`, `ingest` and `coordinating_only`. A
node can contribute to multiple counts as it can have multiple roles. Every
node is implicitly a coordinating node, so whenever a node has no explicit
roles, it will be counted as coordinating only.

==== Removed shard `version` information from `/_cluster/state` routing table

We now store allocation id's of shards in the cluster state and use that to 
select primary shards instead of the version information. 

==== Node roles are not part of node attributes anymore

Node roles are now returned in a specific section, called `roles`, as part of
nodes stats and nodes info response. The new section is an array that holds all
the different roles that each node fulfills. In case the array is returned
empty, that means that the node is a coordinating only node.

==== Forbid unquoted JSON

Previously, JSON documents were allowed with unquoted field names, which isn't
strictly JSON and broke some Elasticsearch clients. If documents were already
indexed with unquoted fields in a previous vesrion of Elasticsearch, some
operations may throw errors. To accompany this, a commented out JVM option has
been added to the `jvm.options` file:
`-Delasticsearch.json.allow_unquoted_field_names`.

Note that this option is provided solely for migration purposes and will be
removed in Elasticsearch 6.0.0.

==== Analyze API changes

The `filters` and `char_filters` parameters have been renamed `filter` and `char_filter`.
The `token_filters` parameter has been removed. Use `filter` instead.

==== `DELETE /_query` endpoint removed

The `DELETE /_query` endpoint provided by the Delete-By-Query plugin has been
removed and replaced by the <<docs-delete-by-query,Delete By Query API>>.

==== Create stored script endpoint removed

The `PUT /_scripts/{lang}/{id}/_create` endpoint that previously allowed to create
 indexed scripts has been removed. Indexed scripts have been replaced
 by <<modules-scripting-stored-scripts,stored scripts>>.

==== Create stored template endpoint removed

The `PUT /_search/template/{id}/_create` endpoint that previously allowed to create
 indexed template has been removed. Indexed templates have been replaced
 by <<pre-registered-templates, Pre-registered templates>>.

==== Remove properties support

Some REST endpoints (e.g., cluster update index settings) supported detecting content in the Java
properties format (line-delimited key=value pairs). This support has been removed.

==== `wait_for_relocating_shards` is now `wait_for_no_relocating_shards` in `/_cluster/health`

The `wait_for_relocating_shards` parameter that used to take a number is now simply a boolean
flag `wait_for_no_relocating_shards`, which if set to true, means the request will wait (up
until the configured timeout) for the cluster to have no shard relocations before returning.
Defaults to false, which means the operation will not wait.