So I am trying to understand how acid state works. The HelloWorld
example has a
type Message = String
data Database = Database [Message]
$(deriveSafeCopy 0 'base ''Database)
-- Transactions are defined to run in either the 'Update' monad
-- or the 'Query' monad.
addMessage :: Message -> Update Database ()
addMessage msg
= do Database messages <- get
put $ Database (msg:messages)
It seems to me that since the Dababase is a list of messages every
update would require acid-state to rewrite the list into the file, so
each update would get slower as the list gets bigger, but what I am
seeing is that updates are constant time regardless of the size of the
list. So how does it work?
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