Question Slow posts and replys when subscriptions are enabled

On my site it takes 15 to 60 seconds to post a new topic or reply.

Rest of site (just browsing) is fast enough.

Have discovered that if, in Kunena config, I set  "Allow subscriptions" to No then the problem goes away and submitting a new post or reply takes just a second or two.

Site has 500k topics, 200k users. Joomla 3.10.12, Kunena 5.2.14

I found and old thread on same topic but its very old:
www.kunena.org/forum/139-K-15-Support-Ar...-subscriptions#25695

Is this a know issue? And ideas on the cause - as the last message in above old post says - it seems that when you click submit to post a topic you then get left hanging in the browser for 30 seconds while some subscription emailing processing is going on in the background - and only after its all done does the user see the page refresh to show their posted topic was submitted OK.

After more testing I have further narrowed down the issue.

The option that really slows my site down is "Category Subscriptions" - rather than individual post subscriptions.

I have now enabled subscriptions to posts but disabled subscriptions to categories.

Posting in case this is causing performance problems for other Kunena users.

Fix:
In Kunena config > Users tab >
Set Category Subscriptions to Disabled

The speed of posting and replying on my site has improved from 10 to 60 seconds before to 1 to 2 seconds now.

Hello,

We had noticed the issue here too on kunena.org, i need to look to find a fix for it