Are the Queries run in coroutines? Or, do I need to call them under a coroutine?

[meta-forte]

Does ktorm run SQL statements & queries by starting a coroutine? or, do I need manage execution of queries under coroutines myself?

thanks

[JasonMing]

AFAIK, ktorm is running in blocking mode(see: org.ktorm.database.Database#executeExpression), the actually query will block the caller's thread.

Which means, ktorm queries should be dispatched to a standalone blocking dispatcher. Especially the operations depend on the transaction, because JdbcTransactionmanager depends on ThreadLocal.

Here is what I do:

private val dbDispatcher = newFixedThreadPoolContext(30, "ktorm-db")

suspend fun <R> db(block: suspend Database.() -> R): R =
    withContext(dbDispatcher) {
        block(db)
    }

So you can simply call db { ... } in any suspend function without worrying about blocking the non-blocking coroutine dispatchers.