Description
Hi,
I recently came across this issue while trying to create a DB transaction per request.
The reason for using a DB transaction per request (which means 1 connection per client) is to keep the returned data consistent (ISOLATION READ COMMITED) as with increased traffic some inconsistencies started to occur on certain queries.
The second reason is having more control over the db connections to support load balancing with dynamic number of read replicas (as the only available solution unfortunately does not support connection pool). However I suppose this can be solved with some effort.
The problem is that when one of the resolvers fails with error (which is not a casual case but happens sometimes), other resolvers keep running. However I need to release the db connection before I send the response which sometimes happens before the rest of resolvers finishes (most of them are data loaders which makes the problem more obvious as the default behaviour is to wait for the next tick until the batch operation runs).
The problem could be resolved by using Promise.allSettled instead of Promise.all. I can't come up with any problem this change could cause except longer time till response in case of error.
Can you please correct me if I'm mistaken or consider this change? Or maybe transactional processing of resolvers is a bad idea in general (although I don't see any reason except the performance gain from using multiple connections per request)
Thanks a lot!