How to process multiple transactions of a user at the same time

[Apple]

This is called a “race condition”, I documented this behaviour here:

Mutex lock/unlock step (to prevent race conditions)

Mutex lock/unlock step (to prevent race conditions) Let’s start with an example: Database Query user_balance: $10 (query takes e.g. 10ms) If balance >= 10: Database Update user_balance: user_balance - $10 Database Query user_balance: $0 What happens if the same user performs the very same server action precisely at the same time? (e.g.: 1ms apart) Database Query user_balance: $10 Database Query user_balance: $10 If balance >= 10: Database Update user_balance: user_balance - $10 If balan…

As you can see, currently Wappler has no built-in protection for this. You’d need to wrap your queries in a database transaction or perform the calculation directly in the SQL query - either way through a Database Custom Query

If you’re using MySQL/MariaDB you can ping @ Hyperbytes, he might be able to help you

If you’re using PostgreSQL try checking this:

SQL to avoid data corruption in race conditions with SERIALIZABLE 🐘 🚀