How to manage transactions in spring data?

Question

PostgreSQL

Good day!
I am doing a training project spring boot + spring data + postgresql. Airline booking. To exclude the possibility of buying extra tickets, I created a table in which there is information about the remaining number of tickets not sold. Instead of using the Serializable isolation level, I want to lock only the row via FOR UPDATE and @Lock(LockModeType.PESSIMISTIC_WRITE). But how to make sure that the transaction is not committed until the payment is confirmed or within a specified time if the payment has not gone through.
Or what approach generally to use in the given situation?

Answer 1

It is not necessary to do it through transactions.
For each "purchase" you create an application in a separate table "booking".
Upon receipt of payment, you sell the ticket, delete the entry from the applications.
With a certain frequency, you go through this table, delete obsolete applications.
Here, yes - we do everything in a transaction.
Accordingly, when calculating the number of available tickets, you count as NUMBER_TICKETS - NUMBER_APPLICATIONS.