From 71084b4c96fcc95ba2e69715831f2f36d84aa70d Mon Sep 17 00:00:00 2001 From: James Roper Date: Tue, 19 Mar 2019 14:59:31 +1100 Subject: [PATCH] Clarified the failure conditions for Read/WriteLocal --- akka-docs/src/main/paradox/distributed-data.md | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/akka-docs/src/main/paradox/distributed-data.md b/akka-docs/src/main/paradox/distributed-data.md index 0d83eb808a..da35215646 100644 --- a/akka-docs/src/main/paradox/distributed-data.md +++ b/akka-docs/src/main/paradox/distributed-data.md @@ -212,6 +212,10 @@ from other nodes might not be visible yet. When using @scala[`WriteLocal`]@java[`writeLocal`] the update is only written to the local replica and then disseminated in the background with the gossip protocol, which can take few seconds to spread to all nodes. +When using `ReadLocal`, you will never receive a `GetFailure` response, since the local replica is always available to +local readers. `WriteLocal` however may still reply with `UpdateFailure` messages, in the event that the `modify` function +threw an exception, or, if using durable storage, if storing failed. + `WriteAll` and `ReadAll` is the strongest consistency level, but also the slowest and with lowest availability. For example, it is enough that one node is unavailable for a `Get` request and you will not receive the value.