Current documentation on using keepAlive

[tao]

I can't seem to figure out if I should or how I should use keepAlive when creating the Client.

I found lots of bugs and old issues mentioning it, and lots of results for keepAlive when searching in the legacy client (https://github.com/elastic/elasticsearch-js-legacy/search?q=keepAlive). However, I don't see any mention of using it now (or no longer needing to use it in the migration guide) and when I search this repository.

I don't see it being used in the proxy example either but I'm worried about not setting up my cClient correctly without it and overloading my self-hosted ElasticSearch cluster.

Can you provide guidance or improve the documentation on when and how to use keepAlive or if it is no longer necessary to specify it when creating the Client?

[delvedor]

Hello!

You can configure the keep-alive functionality with the agent option. But unless you have a very good reason to disable keep-alive, then don't worry about it. The client will enable it by default and will avoid closing sockets behind the scenes. As result, the overall pressure on your cluster will be lower.

[tao]

Ok, so it's enabled by default. It might be good to update the docs to mention that somewhere.

[sibelius]

I'm getting a lot of ConnectionError: Socket connection timeout when doing a lot of requests using elastic search client

is there a way to fix it?

keepAlive is still an option?

this is my config

new Client({
      node: config.ELASTICSEARCH,
      maxRetries: 2,
      requestTimeout: 3000,
    })
    ````

[JoshMock]

@sibelius The default for requestTimeout is 30000. By reducing the default by a factor of 10, you're very likely to experience timeouts on slower requests.

[JoshMock]

Ok, so it's enabled by default. It might be good to update the docs to mention that somewhere.

It does mention on the intro page of the docs that connections are persistent and keep-alive. And on the basic config page it notes that disabling the HTTP agent disables keep-alive connections.

I've also opened a PR to add a section about keep-alive connections to the connection config page. If there are other places we can make that more clear, let me know.