Cluster load while updating mappings of live production indexes

I need to add a couple of new keyword fields to a significant quantity of production indexes which are using a mapping with dynamic: strict
I was hoping to be able to use a wildcard with the update mapping API, something like

PUT /my-index-prefix-*/_mapping
  "properties": {
    "email": {
      "type": "keyword"

I am concerned about the safety of running this against heavily used production indexes. Should I expect some kind of impact on the cluster performance while the mappings are updated?


Welcome to our community! :smiley:

Yes, there is a cost to doing this, so it'll likely impact your cluster traffic.

Hi Mark, thank you for your answer!
Is there a recommended way for doing this while minimizing the performance impact? Maybe applying updates to one index at a time instead of using a wildcard update?
Or it's better to create new indexes with the updated mapping and then perform a reindex?

many thanks

I'd start by doing a few, and then seeing what sort of impact it has.
Ultimately it'll depend on how many indices are being updated.

ok, thanks I'll give it a try!

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