Slick does not commit transaction on AWS postgres DB - postgresql

Question

We have an issue with slick 3.0 and a postgres database (9.5) on AWS, where slick opens a transaction but does not seem to commit it, leaving an open connection "idle in transaction" and the futures never complete.
We are just calling db.run(saveRow(row).transactionally.asTry), where
private def saveRow(row: Row): DBIO[Int] = {
val getExistingRow: DBIO[Option[Row]] = table.filter(_.id === row.id).result.headOption
getExistingRow.flatMap((existingRow: Option[Row]) =>
existingRow match {
case None => table += row
case Some(row) =>
table.filter(_.id === row.id).map(_.propety).update(row.property)
}
)
}
Now the first select statement created from getExistingRow already does not complete. It works locally, but when running it in production on AWS, all prepared statements are never commited. Logs from slick.backend just show
#1: Start transaction
#2: StreamingInvokerAction$HeadOptionAction [select ...]
We would expect to get the following further logs from slick.backend (we see them locally), but we don't see them.
#3: SingleInsertAction [insert into ...]
#4: Commit
Is there some configuration setting I need to provide for this to work on the side of Slick, HikariCP or the postgres database that could fix this? Any other ideas on how to fix this issue?

Answer 1

It was actually caused by using the play execution context. When switching to the scala default execution context it worked fine.