Kibana: Force merge warning about read-only index on management UI

[stsourlidakis]

The confirmation dialog for a force merge through the index management UI still has the warning message based on the ES 6.3 docs which is a bit misleading because you can't force merge an index that is in read-only mode.
I think PR 20264 and issue 19872 are related to the last change.

The ES docs seem to be updated according to this issue and this PR

[elasticmachine]

Pinging @elastic/kibana-app-arch (Team:AppArch)

[elasticmachine]

Pinging @elastic/es-ui (Team:Elasticsearch UI)

[vishalsharma14]

Hi @stsourlidakis @cjcenizal, I would like to contribute on this if it's still open

[cjcenizal]

Yes, please! Thank you @vishalsharma14! Do you need any guidance?

[vishalsharma14]

@cjcenizal Just wanted to confirm a few things. It only needs change here: https://github.com/bmcconaghy/kibana/blob/652cedfd60b76f0934093d47da8a5ca0ed580eb4/x-pack/plugins/index_management/public/sections/index_list/components/index_actions_context_menu/index_actions_context_menu.js#L244?
And this is the updated warning message: https://www.elastic.co/guide/en/elasticsearch/reference/current/tune-for-search-speed.html#_force_merge_read_only_indices?
Also, the PR should be to 6.x branch?

[cjcenizal]

@vishalsharma14 To clarify, the message that needs to be changed is located here: https://github.com/elastic/kibana/blob/master/x-pack/plugins/index_management/public/application/sections/home/index_list/index_actions_context_menu/index_actions_context_menu.js#L364

The new message should read:

Don't force-merge indices to which you're still writing, or to which you'll write again in the future. Instead, rely on the automatic background merge process to perform merges as needed to keep the index running smoothly. If you write to a force-merged index then its performance may become much worse.

This PR should target the master branch. Once you create your PR I'll automatically get pinged to provide a code review and can help you more at that point.

[vishalsharma14]

@cjcenizal Thanks! I'll work on it and create a PR soon.