Running Concurrent Update Mutations to the same node(@id) causes RPC error and transaction to be aborted. Doesn't Auto Retry #5341
Description
What version of Dgraph are you using?
v20.03.1
Have you tried reproducing the issue with the latest release?
Yes
What is the hardware spec (RAM, OS)?
High Availability K8s cluster as built with (https://github.com/dgraph-io/dgraph/blob/master/contrib/config/kubernetes/dgraph-ha/dgraph-ha.yaml)
Steps to reproduce the issue (command/config used to run Dgraph).
Schema:
type Workspace {
workspaceId: String! @search(by: [hash]) @id
}
interface Id {
key: String! @search(by: [hash]) @id
onWorkspace: [Workspace]!
hasTraits: [Traits]
hasGroupTraits: [GroupTraits]
}
type AnonymousId implements Id {
email: [Email] @hasInverse(field: anonymousId)
userId: [UserId] @hasInverse(field: anonymousId)
}
Mutations:
{ upd1: updateAnonymousId(input: {
filter: { key: {eq: "id2"}},
set: { onWorkspace: [{workspaceId:"${workspaceId}"}]
}) { anonymousid{
key
}
}
}
{ upd2: updateAnonymousId(input: {
filter: { key: {eq: "id2"}},
set: { onWorkspace: [{workspaceId:"${workspaceId2}"}]
}) { anonymousid{
key
}
}
}
If you run those 2 mutations concurrently(Might need to run many of them at the same time). It collides on updating the same node then produces the following error:
mutation updateAnonymousId failed because Dgraph mutation failed because rpc error: code = Aborted desc = Transaction has been aborted. Please retry
Expected behaviour and actual result.
Expected Behaviour: - Automatically retrying or dealing with multiple mutations trying to update the same node
Actual Result: - Gives an error when trying to update and fails the entire transaction. Error: mutation updateAnonymousId failed because Dgraph mutation failed because rpc error: code = Aborted desc = Transaction has been aborted. Please retry
In the straight GRPC GQL+- spec there is an expectation that you would retry the transaction by yourself with a backoff, but the GQL spec seems to be a layer of abstraction in front of that. As such it feels like the mutations shouldn't need to be retried, but rather the server side would retry it.