What is the recommended approach to use Exposed in...

# exposed

[Renan Kummer]

What is the recommended approach to use Exposed in Ktor apps? I'm aware of transaction and newSuspendedTransaction functions, so far in my app I've used newSuspendedTransaction . However, I have a scenario where I'll need to call a set of functions that each interact with the database using newSuspendedTransaction , and if something goes wrong, I'd like the whole set to be rolled back instead of just the transaction that went wrong. The issue doesn't happen if I use transaction, but then I'm afraid I won't use Ktor appropriately since coroutines won't be used at all and the thread will be blocked until all the queries are done.

Any suggestions?

[Renan Kummer]

Just realized that withSuspendedTransaction reuses the parent transaction. Did I get this right?

[Renan Kummer]

I created the following helper function to test the behavior and it seems to rollback all parents as well:

private suspend fun onSuspendedTransaction(f: suspend Transaction.() -> Unit) {
  val currentTransaction = TransactionManager.currentOrNull()
    
  if (currentTransaction == null) {

newSuspendedTransaction(Dispatchers.IO) { f() }
    } else {
        currentTransaction.withSuspendTransaction(Dispatchers.IO) { f() }
    }
}

My test:

try {         
    onSuspendedTransaction {
      onSuspendedTransaction {
        items2.forEach {              
          insertGame(it) }
        }
      
      items1.forEach {    
        insertGame(it) 
      }
    
      onSuspendedTransaction {
        items3.forEach {  
          insertGame(it) 
        }
        throw Exception()
      }
    }
} catch (_: Exception) {}