[discrete]
[[breaking_80_reindex_changes]]
==== Reindex changes

//NOTE: The notable-breaking-changes tagged regions are re-used in the
//Installation and Upgrade Guide

//tag::notable-breaking-changes[]
//end::notable-breaking-changes[]

.Reindex from remote now re-encodes URL-encoded index names.
[%collapsible]
====
*Details* +
Reindex from remote would previously allow URL-encoded index names and not
re-encode them when generating the search request for the remote host. This
leniency has been removed such that all index names are correctly encoded when
reindex generates remote search requests.

*Impact* +
Specify unencoded index names for reindex from remote requests.
====

.Reindex-related REST API endpoints containing mapping types have been removed.
[%collapsible]
====
*Details* +
The `/{index}/{type}/_delete_by_query` and `/{index}/{type}/_update_by_query` REST endpoints have been removed in favour of `/{index}/_delete_by_query` and `/{index}/_update_by_query`, since indexes no longer contain types, these typed endpoints are obsolete.

*Impact* +
Use the replacement REST API endpoints. Requests submitted to API endpoints
that contain a mapping type will return an error.
====


.In the reindex, delete by query, and update by query APIs, the `size` parameter has been renamed.
[%collapsible]
====
*Details* +
Previously, a `_reindex` request had two different size specifications in the body:

- Outer level, determining the maximum number of documents to process
- Inside the `source` element, determining the scroll/batch size.

The outer level `size` parameter has now been renamed to `max_docs` to
avoid confusion and clarify its semantics.

Similarly, the `size` parameter has been renamed to `max_docs` for
`_delete_by_query` and `_update_by_query` to keep the 3 interfaces consistent.

*Impact* +
Use the replacement parameters. Requests containing the `size` parameter will
return an error.
====