[[breaking_70_settings_changes]]

=== Settings changes

==== Percolator

* The deprecated `index.percolator.map_unmapped_fields_as_string` setting has been removed in favour of
  the `index.percolator.map_unmapped_fields_as_text` setting.

==== Index thread pool

* Internally, single-document index/delete/update requests are executed as bulk
  requests with a single-document payload. This means that these requests are
  executed on the bulk thread pool. As such, the indexing thread pool is no
  longer needed and has been removed. As such, the  settings
  `thread_pool.index.size` and `thread_pool.index.queue_size` have been removed.

[[write-thread-pool-fallback]]
==== Write thread pool fallback

* The bulk thread pool was replaced by the write thread pool in 6.3.0. However,
  for backwards compatibility reasons the name `bulk` was still usable as fallback
  settings `thread_pool.bulk.size` and `thread_pool.bulk.queue_size` for
  `thread_pool.write.size` and `thread_pool.write.queue_size`, respectively, and
  the system property `es.thread_pool.write.use_bulk_as_display_name` was
  available to keep the display output in APIs as `bulk` instead of `write`.
  These fallback settings and this system property have been removed.