Eddb

eddb is a distributed database for unstructured data

Functions

get

get will retrive the data from all neighbors and check which update is the newest. Only the newest data will be returned.

Note

This has no affect on the data on the current node. If you want the data to be merged, call the sync function

Database.Database.get_worker("worker1")
|> GenServer.call({:get, "topic", "key"})

get_local

get_local will only retrive the newest data from the current node. Thus, this operation is significantly faster.

Database.Database.get_worker("worker1")
|> GenServer.call({:get_local, "topic", "key"})

put

put will store the data on the current node. Data with the same key in the same topic will be overwritten, but the old data will be kept in the history.

Database.Database.get_worker("worker1")
|> GenServer.call({:put, "topic", "key", "value"})

put (With optimistic locking)

put with optimistic locking is similar to the normal put operation. However, you can specify the expected current state and only if the expection matches with the data on the node, the new data will be stored.

Note

Contrary to the normal put operation will this operation check the expected data on all nodes and compare it with the newest data

Database.Database.get_worker("worker1")
|> GenServer.call({:put, "topic", "key", "currentValue", "newValue"})

sync

sync will merge the data from all neighbors. The data with the newest timestamp is considered the current state.

Database.Database.get_worker("worker1")
|> GenServer.call({:sync, "topic"})

delete

delete will delete data locally.

A better solution would be setting the value to nil or any other placeholder value as the newer timestamp would make it the source-of-truth.

Database.Database.get_worker("worker1")
|> GenServer.call({:delete, "topic", "key"})

# Or use something like this to delete the data "globally":

Node.list()
|> Enum.map(fn node ->
  Database.Database.get_remote_worker(node, "worker1")
  |> GenServer.call({:delete, "topic", "key"})
end