elasticsearch/docs/reference/migration/migrate_8_0/indices.asciidoc

[float]
[[breaking_80_indices_changes]]
=== Indices 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[]


.The force merge API's `max_num_segments` and `only_expunge_deletes` parameters cannot both be specified in the same request.
[%collapsible]
====
*Details* +
Previously, the force merge API allowed the parameters `only_expunge_deletes`
and `max_num_segments` to be set to a non default value at the same time. But
the `max_num_segments` was silently ignored when `only_expunge_deletes` is set
to `true`, leaving the false impression that it has been applied.

*Impact* +
When using the {ref}/indices-forcemerge.html[force merge API], do not specify
values for both the `max_num_segments` and `only_expunge_deletes` parameters.
Requests that include values for both parameters will return an error.
====

.The `index.force_memory_term_dictionary` setting has been removed.
[%collapsible]
====
*Details* +
The `index.force_memory_term_dictionary` setting was introduced in 7.0 as a
temporary measure to allow users to opt-out of the optimization that leaves the
term dictionary on disk when appropriate. This optimization is now mandatory
and the setting is removed.

*Impact* +
Discontinue use of the `index.force_memory_term_dictionary` index setting.
Requests that include this setting will return an error.
====

.The put index template API's `template` parameter has been removed.
[%collapsible]
====
*Details* +
In 6.0, we deprecated the `template` parameter in put index template requests
in favor of using `index_patterns`. Support for the `template` parameter is now
removed in 8.0.

*Impact* +
Use the {ref}/indices-templates-v1.html[put index template API]'s
`index_patterns` parameter. Requests that include the `template` parameter will
return an error.
====

.Synced flush has been removed.
[%collapsible]
====
*Details* +
Synced flush was deprecated in 7.6 and is removed in 8.0. Use a regular flush
instead as it has the same effect as a synced flush in 7.6 and later.

*Impact* +
Use the {ref}/indices-flush.html[flush API]. Requests to the
`/<index>/flush/synced` or `/flush/synced` endpoints will return an error.
====

.The `index.soft_deletes.enabled` setting has been removed.
[%collapsible]
====
*Details* +
Creating indices with soft deletes disabled was deprecated in 7.6 and
is no longer supported in 8.0. The `index.soft_deletes.enabled` setting
can no longer be set to `false`. 

*Impact* +
Discontinue use of the `index.soft_deletes.enabled` index setting. Requests that
set `index.soft_deletes.enabled` to `false` will return an error.
====

.The `index.translog.retention.age` and `index.translog.retention.size` settings have been removed.
[%collapsible]
====
*Details* +
Translog retention settings `index.translog.retention.age` and
`index.translog.retention.size` were effectively ignored in 7.4, deprecated in
7.7, and removed in 8.0 in favor of
{ref}/index-modules-history-retention.html[soft deletes].

*Impact* +
Discontinue use of the `index.translog.retention.age` and
`index.translog.retention.size` index settings. Requests that
include these settings will return an error.
====