Answered: It takes too long to save when user ask questions, why?

Try applying these changes: https://github.com/q2a/question2answer/pull/910

If you want to apply additional performance improvements at the expense of not being able to search for posts (like not updating the qa_words table), that will boost performance more.

But please, DO let me know the times things take BEFORE these changes and AFTER these changes. To properly test it, do this:

1. Backup your current file (the one with those changes)
2. Replace it with the official standard file
3. Run the tests I mentioned in the comment above and take a note (you can measure using the web browser inspector, in the networking tab you'll see the requests)
4. Apply the changes from my pull request
5. Execute step 3 again
6. Share the results here