use core::borrow::Borrow; use std::sync::Arc; use log::warn; use serde_bytes::ByteBuf; use sled::Transactional; use tokio::sync::Notify; use garage_util::data::*; use garage_util::error::*; use garage_rpc::system::System; use crate::crdt::Crdt; use crate::gc::GcTodoEntry; use crate::replication::*; use crate::schema::*; pub struct TableData { system: Arc, pub(crate) instance: F, pub(crate) replication: R, pub store: sled::Tree, pub(crate) merkle_tree: sled::Tree, pub(crate) merkle_todo: sled::Tree, pub(crate) merkle_todo_notify: Notify, pub(crate) gc_todo: sled::Tree, } impl TableData where F: TableSchema, R: TableReplication, { pub fn new(system: Arc, instance: F, replication: R, db: &sled::Db) -> Arc { let store = db .open_tree(&format!("{}:table", F::TABLE_NAME)) .expect("Unable to open DB tree"); let merkle_tree = db .open_tree(&format!("{}:merkle_tree", F::TABLE_NAME)) .expect("Unable to open DB Merkle tree tree"); let merkle_todo = db .open_tree(&format!("{}:merkle_todo", F::TABLE_NAME)) .expect("Unable to open DB Merkle TODO tree"); let gc_todo = db .open_tree(&format!("{}:gc_todo_v2", F::TABLE_NAME)) .expect("Unable to open DB tree"); Arc::new(Self { system, instance, replication, store, merkle_tree, merkle_todo, merkle_todo_notify: Notify::new(), gc_todo, }) } // Read functions pub fn read_entry(&self, p: &F::P, s: &F::S) -> Result, Error> { let tree_key = self.tree_key(p, s); if let Some(bytes) = self.store.get(&tree_key)? { Ok(Some(ByteBuf::from(bytes.to_vec()))) } else { Ok(None) } } pub fn read_range( &self, p: &F::P, s: &Option, filter: &Option, limit: usize, ) -> Result>, Error> { let partition_hash = p.hash(); let first_key = match s { None => partition_hash.to_vec(), Some(sk) => self.tree_key(p, sk), }; let mut ret = vec![]; for item in self.store.range(first_key..) { let (key, value) = item?; if &key[..32] != partition_hash.as_slice() { break; } let keep = match filter { None => true, Some(f) => { let entry = self.decode_entry(value.as_ref())?; F::matches_filter(&entry, f) } }; if keep { ret.push(Arc::new(ByteBuf::from(value.as_ref()))); } if ret.len() >= limit { break; } } Ok(ret) } // Mutation functions // When changing this code, take care of propagating modifications correctly: // - When an entry is modified or deleted, call the updated() function // on the table instance // - When an entry is modified or deleted, add it to the merkle updater's todo list. // This has to be done atomically with the modification for the merkle updater // to maintain consistency. The merkle updater must then be notified with todo_notify. // - When an entry is updated to be a tombstone, add it to the gc_todo tree pub(crate) fn update_many>(&self, entries: &[T]) -> Result<(), Error> { for update_bytes in entries.iter() { self.update_entry(update_bytes.borrow().as_slice())?; } Ok(()) } pub(crate) fn update_entry(&self, update_bytes: &[u8]) -> Result<(), Error> { let update = self.decode_entry(update_bytes)?; let tree_key = self.tree_key(update.partition_key(), update.sort_key()); let changed = (&self.store, &self.merkle_todo).transaction(|(store, mkl_todo)| { let (old_entry, old_bytes, new_entry) = match store.get(&tree_key)? { Some(old_bytes) => { let old_entry = self .decode_entry(&old_bytes) .map_err(sled::transaction::ConflictableTransactionError::Abort)?; let mut new_entry = old_entry.clone(); new_entry.merge(&update); (Some(old_entry), Some(old_bytes), new_entry) } None => (None, None, update.clone()), }; // Scenario 1: the value changed, so of course there is a change let value_changed = Some(&new_entry) != old_entry.as_ref(); // Scenario 2: the value didn't change but due to a migration in the // data format, the messagepack encoding changed. In this case // we have to write the migrated value in the table and update // the associated Merkle tree entry. let new_bytes = rmp_to_vec_all_named(&new_entry) .map_err(Error::RmpEncode) .map_err(sled::transaction::ConflictableTransactionError::Abort)?; let encoding_changed = Some(&new_bytes[..]) != old_bytes.as_ref().map(|x| &x[..]); if value_changed || encoding_changed { let new_bytes_hash = blake2sum(&new_bytes[..]); mkl_todo.insert(tree_key.clone(), new_bytes_hash.as_slice())?; store.insert(tree_key.clone(), new_bytes)?; Ok(Some((old_entry, new_entry, new_bytes_hash))) } else { Ok(None) } })?; if let Some((old_entry, new_entry, new_bytes_hash)) = changed { let is_tombstone = new_entry.is_tombstone(); self.instance.updated(old_entry, Some(new_entry)); self.merkle_todo_notify.notify_one(); if is_tombstone { // We are only responsible for GC'ing this item if we are the // "leader" of the partition, i.e. the first node in the // set of nodes that replicates this partition. // This avoids GC loops and does not change the termination properties // of the GC algorithm, as in all cases GC is suspended if // any node of the partition is unavailable. let pk_hash = Hash::try_from(&tree_key[..32]).unwrap(); let nodes = self.replication.write_nodes(&pk_hash); if nodes.first() == Some(&self.system.id) { GcTodoEntry::new(tree_key, new_bytes_hash).save(&self.gc_todo)?; } } } Ok(()) } pub(crate) fn delete_if_equal(self: &Arc, k: &[u8], v: &[u8]) -> Result { let removed = (&self.store, &self.merkle_todo).transaction(|(store, mkl_todo)| { if let Some(cur_v) = store.get(k)? { if cur_v == v { store.remove(k)?; mkl_todo.insert(k, vec![])?; return Ok(true); } } Ok(false) })?; if removed { let old_entry = self.decode_entry(v)?; self.instance.updated(Some(old_entry), None); self.merkle_todo_notify.notify_one(); } Ok(removed) } pub(crate) fn delete_if_equal_hash( self: &Arc, k: &[u8], vhash: Hash, ) -> Result { let removed = (&self.store, &self.merkle_todo).transaction(|(store, mkl_todo)| { if let Some(cur_v) = store.get(k)? { if blake2sum(&cur_v[..]) == vhash { store.remove(k)?; mkl_todo.insert(k, vec![])?; return Ok(Some(cur_v)); } } Ok(None) })?; if let Some(old_v) = removed { let old_entry = self.decode_entry(&old_v[..])?; self.instance.updated(Some(old_entry), None); self.merkle_todo_notify.notify_one(); Ok(true) } else { Ok(false) } } // ---- Utility functions ---- pub(crate) fn tree_key(&self, p: &F::P, s: &F::S) -> Vec { let mut ret = p.hash().to_vec(); ret.extend(s.sort_key()); ret } pub(crate) fn decode_entry(&self, bytes: &[u8]) -> Result { match rmp_serde::decode::from_read_ref::<_, F::E>(bytes) { Ok(x) => Ok(x), Err(e) => match F::try_migrate(bytes) { Some(x) => Ok(x), None => { warn!("Unable to decode entry of {}: {}", F::TABLE_NAME, e); for line in hexdump::hexdump_iter(bytes) { debug!("{}", line); } Err(e.into()) } }, } } pub fn gc_todo_len(&self) -> usize { self.gc_todo.len() } }