Stop search if client has disconnected

[ebuildy (Thomas Decaux)]

Is it possible to stop the search if the main HTTP connection is closed by the client?

My use case: "a web-site with Nginx+php+elasticsearch, public user does a search and closes the page immediately"

• Nginx connection is closed
• php-fpm is closed (via http://nginx.org/en/docs/http/ngx_http_fastcgi_module.html#fastcgi_ignore_client_abort)
• With php function http://php.net/manual/en/function.register-shutdown-function.php I can execute some code just before exiting
• elasticsearch query still continue

I think it's possible with task API, but I am wondering if there is a more elegant way.

[dadoonet (David Pilato)]

Do you mean that you have very long queries running? Task API might help indeed but only for long queries (which you should try to avoid anyway).

[ebuildy (Thomas Decaux)]

It's not about long queries, we have timeout for that, it's about "zombie" search, when the end-user has left the web site, but elasticsearch is still searching.

I must setup a monitoring to count how many ES queries are "abandoned" by Php, maybe it's very little, but I am curious to know if it's possible to optimize our ES cluster by stoping "zombie" searches.

[dadoonet (David Pilato)]

Do you mean that it is still consuming resources on elasticsearch end?
That should not happen AFAIK.

[forloop (Russ Cam)]

I think the Task API's X-Opaque-Id header support is the most suitable mechanism for this purpose; if a value is supplied in the search call, it can be used to cancel the tasks with that value after client has aborted.