Fix table RPC to not be interruptible

This commit is contained in:
Alex 2020-04-12 23:05:53 +02:00
parent 2bea76ce16
commit 43ce5e4ab4
2 changed files with 25 additions and 34 deletions

33
TODO
View file

@ -1,29 +1,16 @@
Object table
------------
Rename version table to object table
In value handle the different versions
So that the table becomes bucket + Sort key = object key -> CRDT(list of versions)
CRDT merge rule:
- keep one complete version (the one with the highest timestamp)
- keep all incomplete versions with timestamps higher than the complete version
Cleanup rule: remove incomplete versions after a given delay (say 24h)
Block table
Replication
-----------
Table is version_UUID -> BTreeMap<(offset, block hash)> OR Deleted (= CRDT top)
- for each interval of tokens, we know the list of nodes that are responsible
- every node watches the current ring and state of the network
- and thus determines the interval of tokens for which they are responsible
Block reference table
---------------------
Table is block_Hash + Sort key: version_UUID -> boolean (true when deleted)
To do list
----------
Since the hash key is the same as for the blocks themselves,
we can simply consider the updates to this table as events that increase/decrease a reference counter.
- important: check block values on read and repare corrupted block contents
- less a priority: hinted handoff
- FIXME in rpc_server when garage shuts down and futures can be interrupted
(tokio::spawn should be replaced by a new function background::spawn_joinable)

View file

@ -76,22 +76,26 @@ async fn handler(
// and the request handler simply sits there waiting for the task to finish.
// (if it's cancelled, that's not an issue)
// (TODO FIXME except if garage happens to shut down at that point)
let write_fut = async move { garage.block_manager.write_block(&m.hash, &m.data).await };
let write_fut = async move {
garage.block_manager.write_block(&m.hash, &m.data).await
};
tokio::spawn(write_fut).await?
}
Message::GetBlock(h) => garage.block_manager.read_block(&h).await,
Message::TableRPC(table, msg) => {
// For now, table RPCs use transactions that are not async so even if the future
// is canceled, the db should be in a consistent state.
if let Some(rpc_handler) = garage.table_rpc_handlers.get(&table) {
rpc_handler
.handle(&msg[..])
.await
.map(|rep| Message::TableRPC(table.to_string(), rep))
} else {
Ok(Message::Error(format!("Unknown table: {}", table)))
}
// Same trick for table RPCs than for PutBlock
let op_fut = async move {
if let Some(rpc_handler) = garage.table_rpc_handlers.get(&table) {
rpc_handler
.handle(&msg[..])
.await
.map(|rep| Message::TableRPC(table.to_string(), rep))
} else {
Ok(Message::Error(format!("Unknown table: {}", table)))
}
};
tokio::spawn(op_fut).await?
}
_ => Ok(Message::Error(format!("Unexpected message: {:?}", msg))),