Why the live database of our client is very slow. I have a custom module name expense then this module will generate a journal entry (account.move) and journal item(account.move.line) 

But the problem is even though I can generate a journal entry with one journal item. It takes a minute or more to post the expense. Why is that? 

Unlike in my demo database, it takes a couple of seconds to post an expense, then I tried to lower the memory_soft, hard and the cpu to 1 in  odoo config to my demo database but still, it's still faster to post an expense.

The live database have memory_hard: 256 and memory_soft: 512. Is the value still lower?