Elasticsearch taking up lots of memory

[Jon12345]

I've been getting some errors with my search lately, and my admin panel in Xenforo shows this:

XFES\Elasticsearch\ConnectException: cURL error 7: Failed to connect to localhost port 9200: Connection refused (see http://curl.haxx.se/libcurl/c/libcurl-errors.html) in src/addons/XFES/Elasticsearch/Api.php at line 390

So I contact my host and they say I have little memory left. It shows elasticsearch taking up 58% of memory and mysql in second at nearly 30%. They are suggesting I upgrade my RAM, which is 6GB. For context, I have 1.6M posts and running litespeed.

Is it usual for elasticsearch to take up this much memory for that number of posts? Same question for mysql. Can I limit that in any way? The budget is saying no to spending more on hosting!

Edit: They also said my PHP memory limits are high, which are 512M. What is a normal PHP memory limit?

 

[Rhodium]

You can limit like here: https://xenforo.com/community/threads/elasticsearch-7-11.191203/

I'm using 512m in elasticsearch for 5m of posts with no crashes.

 

[Jon12345]

Big thanks @Rhodium. Saved me a big headache!