MsSql/PgSql: Mutations should be done in the same transaction as other mutations in the same request

[JelteF]

Multiple mutations should be part of the same transaction. That way they can be rolled back in an atomic way. It also ensures that no unexpected data is returned in the result of a mutation in case of concurrent updates.

[Aniruddh25]

@gledis69, fyi: https://github.com/Azure/project-hawaii/blob/main/rfcs/transactions.md if this helps clarify any design issues. Please put in this issue about specific concerns/areas for which you need help with to address this issue - so we can discuss and get it moving.

[Aniruddh25]

@JelteF, I changed the title to reflect ALL MUTATIONS ARE in the same transaction. BUT we will NOT ensure that mutations and a subsequent query in the same POST payload(i.e. same GraphQL request) to be in same transaction - this is as agreed on in our discussions and mentioned in the RFC https://github.com/Azure/project-hawaii/blob/main/rfcs/transactions.md

[Aniruddh25]

Difficulties due not having the required amount of context from hotchocolate to BEGIN and END TRANSACTION in the right places. Moving to M 1.5 as this is an edge case enhancement.