Low level REST client for Java revision history?

[TimWard]

The documentation says "The low-level REST client is subject to the same release cycle as Elasticsearch. Replace the version with the desired client version, first released with 5.0.0-alpha4. There is no relation between the client version and the Elasticsearch version that the client can communicate with. The low-level REST client is compatible with all Elasticsearch versions."

Which suggests that there's no need to update to a new version of the client when upgrading ES from 5.6 -> 6.2. However there is a version 6.2.4 of the low level REST client.

But I can't find a revision history for this client, to help me decide whether I want to upgrade. Can someone point me at it please?

[javanna (Luca Cavanna)]

Good question. Compatibility is fine, but given that the client doesn't have its own release cycle, we "only" get to release it whenever we release Elasticsearch. That means that improvements will be made mainly on master and 6.x, only bugfixes are backported to 5.6.

I would look at the closed PRs that are labelled ":Core/Java Low Level REST Client", each PR has also one or more label versions that tell which version the change is/will be released with: https://github.com/elastic/elasticsearch/pulls?utf8=✓&q=is%3Apr+label%3A"%3ACore%2FJava+Low+Level+REST+Client"+is%3Aclosed .

I found this fix which is probably interesting for you: "hosts marked dead for the first time should not be immediately retried" (https://github.com/elastic/elasticsearch/pull/29230).

So the final answer is: you don't have to upgrade, but if you have the chance it is probably better, not necessarily while upgrading though. The benefit of upgrading the low-level client is that some bugs were hopefully fixed, and some other improvements were merged in the meantime as well.

Cheers
Luca