[Feedback]: "Reindex documents" API documentation does not describe meaning of dest.routing parameter

[pmoncznik]

Was the documentation helpful?

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What documentation page is affected

https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-reindex#operation-reindex-body-application-json-dest-routing

Description

The Elasticsearch 8 API docs included a nice description of how to use the dest.routing parameter to control routing:

Reindex routing

By default if _reindex sees a document with routing then the routing is preserved unless it’s changed by the script. You can set routing on the dest request to change this:

keep
Sets the routing on the bulk request sent for each match to the routing on the match. This is the default value.
discard
Sets the routing on the bulk request sent for each match to null.
=<some text>
Sets the routing on the bulk request sent for each match to all text after the =.

But the new documentation page doesn't seem to describe at all what the parameter means or how to use it.