Running

go run dynamo.go

Output

Prints database operations and streamed live queries.

Implementation

1. Gossip membership

2. N = 3 Replication

3. Rehash regions on node adds and detected node failures

4. Key-object (map) stores as in memory maps

   a. Storing maps under keys allows for specification of which fields to update (fields are sparse--can be empty for some objects). put() interface updates specified fields

5. Live query (key + set of fields to listen to updates on)

   a. Store stream requests within object to be streamed from

    someHashKey {
        accountType: gold,
        balance: 100,
        name: Alice
    }
    
    stream(someHashKey, {balance})
    
    someHashKey {
        accountType: gold,
        balance: 100,
        name: Alice,
        stream: balance
    }
   

   On subsequent put operations for someHashKey, if balance is included in the put, its new value can be streamed to clients via a message queue by reading the stream value of the stored object.

   To support multiple streams for an object, multi-dimensional maps can be used (we leave this to a real implementation):

    someHashKey {
        accountType: gold,
        balance: 100,
        name: Alice
    }
    
    stream(someHashKey, {balance})
    stream(someHashKey, {accountType, balance, name})
    
    someHashKey {
        accountType: gold,
        balance: 100,
        name: Alice,
        stream: {
            hash(balance): balance
            hash(accountType,balance,name): accountType,balance,name
        }
    }