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-rw-r--r--src/model/block.rs10
-rw-r--r--src/table/data.rs2
-rw-r--r--src/table/gc.rs108
3 files changed, 76 insertions, 44 deletions
diff --git a/src/model/block.rs b/src/model/block.rs
index 3f40aaab..8b1919bb 100644
--- a/src/model/block.rs
+++ b/src/model/block.rs
@@ -1,3 +1,4 @@
+use std::convert::TryInto;
use std::path::{Path, PathBuf};
use std::sync::Arc;
use std::time::Duration;
@@ -422,7 +423,7 @@ impl BlockManager {
async fn resync_iter(&self, must_exit: &mut watch::Receiver<bool>) -> Result<bool, Error> {
if let Some((time_bytes, hash_bytes)) = self.resync_queue.pop_min()? {
- let time_msec = u64_from_be_bytes(&time_bytes[0..8]);
+ let time_msec = u64::from_be_bytes(time_bytes[0..8].try_into().unwrap());
let now = now_msec();
if now >= time_msec {
let hash = Hash::try_from(&hash_bytes[..]).unwrap();
@@ -705,13 +706,6 @@ impl BlockManagerLocked {
}
}
-fn u64_from_be_bytes<T: AsRef<[u8]>>(bytes: T) -> u64 {
- assert!(bytes.as_ref().len() == 8);
- let mut x8 = [0u8; 8];
- x8.copy_from_slice(bytes.as_ref());
- u64::from_be_bytes(x8)
-}
-
/// Describes the state of the reference counter for a block
#[derive(Clone, Copy, Debug)]
enum RcEntry {
diff --git a/src/table/data.rs b/src/table/data.rs
index 13ec62bf..fb0b6d02 100644
--- a/src/table/data.rs
+++ b/src/table/data.rs
@@ -55,7 +55,7 @@ where
.expect("Unable to open DB Merkle TODO tree");
let gc_todo = db
- .open_tree(&format!("{}:gc_todo", name))
+ .open_tree(&format!("{}:gc_todo_v2", name))
.expect("Unable to open DB tree");
Arc::new(Self {
diff --git a/src/table/gc.rs b/src/table/gc.rs
index cbd91b3a..98d7c95d 100644
--- a/src/table/gc.rs
+++ b/src/table/gc.rs
@@ -1,4 +1,5 @@
use std::collections::HashMap;
+use std::convert::TryInto;
use std::sync::Arc;
use std::time::Duration;
@@ -13,6 +14,7 @@ use tokio::sync::watch;
use garage_util::data::*;
use garage_util::error::*;
+use garage_util::time::*;
use garage_rpc::system::System;
use garage_rpc::*;
@@ -24,6 +26,11 @@ use crate::schema::*;
const TABLE_GC_BATCH_SIZE: usize = 1024;
const TABLE_GC_RPC_TIMEOUT: Duration = Duration::from_secs(30);
+// GC delay for table entries: 1 day (24 hours)
+// (the delay before the entry is added in the GC todo list
+// and the moment the garbage collection actually happens)
+const TABLE_GC_DELAY: Duration = Duration::from_secs(24 * 3600);
+
pub(crate) struct TableGc<F: TableSchema + 'static, R: TableReplication + 'static> {
system: Arc<System>,
data: Arc<TableData<F, R>>,
@@ -72,35 +79,49 @@ where
async fn gc_loop(self: Arc<Self>, mut must_exit: watch::Receiver<bool>) {
while !*must_exit.borrow() {
match self.gc_loop_iter().await {
- Ok(true) => {
+ Ok(None) => {
// Stuff was done, loop immediately
- continue;
}
- Ok(false) => {
- // Nothing was done, sleep for some time (below)
+ Ok(Some(wait_delay)) => {
+ // Nothing was done, wait specified delay.
+ select! {
+ _ = tokio::time::sleep(wait_delay).fuse() => {},
+ _ = must_exit.changed().fuse() => {},
+ }
}
Err(e) => {
warn!("({}) Error doing GC: {}", self.data.name, e);
}
}
- select! {
- _ = tokio::time::sleep(Duration::from_secs(10)).fuse() => {},
- _ = must_exit.changed().fuse() => {},
- }
}
}
- async fn gc_loop_iter(&self) -> Result<bool, Error> {
+ async fn gc_loop_iter(&self) -> Result<Option<Duration>, Error> {
+ let now = now_msec();
+
let mut entries = vec![];
let mut excluded = vec![];
// List entries in the GC todo list
// These entries are put there when a tombstone is inserted in the table
- // This is detected and done in data.rs in update_entry
+ // (see update_entry in data.rs)
for entry_kv in self.data.gc_todo.iter() {
let (k, vhash) = entry_kv?;
let mut todo_entry = GcTodoEntry::parse(&k, &vhash);
+ if todo_entry.deletion_time() > now {
+ if entries.is_empty() && excluded.is_empty() {
+ // If the earliest entry in the todo list shouldn't yet be processed,
+ // return a duration to wait in the loop
+ return Ok(Some(Duration::from_millis(
+ todo_entry.deletion_time() - now,
+ )));
+ } else {
+ // Otherwise we have some entries to process, do a normal iteration.
+ break;
+ }
+ }
+
let vhash = Hash::try_from(&vhash[..]).unwrap();
// Check if the tombstone is still the current value of the entry.
@@ -134,8 +155,9 @@ where
// and for which they are still currently tombstones in the table.
if entries.is_empty() {
- // Nothing to do in this iteration
- return Ok(false);
+ // Nothing to do in this iteration (no entries present)
+ // Wait for a default delay of 60 seconds
+ return Ok(Some(Duration::from_secs(60)));
}
debug!("({}) GC: doing {} items", self.data.name, entries.len());
@@ -181,7 +203,7 @@ where
}
if errs.is_empty() {
- Ok(true)
+ Ok(None)
} else {
Err(Error::Message(
errs.into_iter()
@@ -189,19 +211,20 @@ where
.collect::<Vec<_>>()
.join(", "),
))
- .err_context("in try_send_and_delete:")
+ .err_context("in try_send_and_delete in table GC:")
}
}
async fn try_send_and_delete(
&self,
nodes: Vec<Uuid>,
- items: Vec<GcTodoEntry>,
+ mut items: Vec<GcTodoEntry>,
) -> Result<(), Error> {
let n_items = items.len();
// Strategy: we first send all of the values to the remote nodes,
- // to ensure that they are aware of the tombstone state.
+ // to ensure that they are aware of the tombstone state,
+ // and that the previous state was correctly overwritten
// (if they have a newer state that overrides the tombstone, that's fine).
// Second, once everyone is at least at the tombstone state,
// we instruct everyone to delete the tombstone IF that is still their current state.
@@ -209,13 +232,14 @@ where
// tombstone in the CRDT lattice, and it will be propagated back to us at some point
// (either just a regular update that hasn't reached us yet, or later when the
// table is synced).
+
// Here, we store in updates all of the tombstones to send for step 1,
// and in deletes the list of keys and hashes of value for step 2.
let mut updates = vec![];
let mut deletes = vec![];
- for item in items {
- updates.push(ByteBuf::from(item.value.unwrap()));
- deletes.push((ByteBuf::from(item.key), item.value_hash));
+ for item in items.iter_mut() {
+ updates.push(ByteBuf::from(item.value.take().unwrap()));
+ deletes.push((ByteBuf::from(item.key.clone()), item.value_hash));
}
// Step 1: ensure everyone is at least at tombstone in CRDT lattice
@@ -250,7 +274,7 @@ where
.try_call_many(
&self.endpoint,
&nodes[..],
- GcRpc::DeleteIfEqualHash(deletes.clone()),
+ GcRpc::DeleteIfEqualHash(deletes),
RequestStrategy::with_priority(PRIO_BACKGROUND)
.with_quorum(nodes.len())
.with_timeout(TABLE_GC_RPC_TIMEOUT),
@@ -260,24 +284,16 @@ where
// GC has been successfull for all of these entries.
// We now remove them all from our local table and from the GC todo list.
- for (k, vhash) in deletes {
+ for item in items {
self.data
- .delete_if_equal_hash(&k[..], vhash)
+ .delete_if_equal_hash(&item.key[..], item.value_hash)
.err_context("GC: local delete tombstones")?;
- self.todo_remove_if_equal(&k[..], vhash)
+ item.remove_if_equal(&self.data.gc_todo)
.err_context("GC: remove from todo list after successfull GC")?;
}
Ok(())
}
-
- fn todo_remove_if_equal(&self, key: &[u8], vhash: Hash) -> Result<(), Error> {
- let _ = self
- .data
- .gc_todo
- .compare_and_swap::<_, _, Vec<u8>>(key, Some(vhash), None)?;
- Ok(())
- }
}
#[async_trait]
@@ -295,7 +311,6 @@ where
GcRpc::DeleteIfEqualHash(items) => {
for (key, vhash) in items.iter() {
self.data.delete_if_equal_hash(&key[..], *vhash)?;
- self.todo_remove_if_equal(&key[..], *vhash)?;
}
Ok(GcRpc::Ok)
}
@@ -307,7 +322,16 @@ where
/// An entry stored in the gc_todo Sled tree associated with the table
/// Contains helper function for parsing, saving, and removing
/// such entry in Sled
+///
+/// Format of an entry:
+/// - key = 8 bytes: timestamp of tombstone
+/// (used to implement GC delay)
+/// n bytes: key in the main data table
+/// - value = hash of the table entry to delete (the tombstone)
+/// for verification purpose, because we don't want to delete
+/// things that aren't tombstones
pub(crate) struct GcTodoEntry {
+ tombstone_timestamp: u64,
key: Vec<u8>,
value_hash: Hash,
value: Option<Vec<u8>>,
@@ -319,6 +343,7 @@ impl GcTodoEntry {
/// serialized value
pub(crate) fn new(key: Vec<u8>, value_hash: Hash) -> Self {
Self {
+ tombstone_timestamp: now_msec(),
key,
value_hash,
value: None,
@@ -328,7 +353,8 @@ impl GcTodoEntry {
/// Parses a GcTodoEntry from a (k, v) pair stored in the gc_todo tree
pub(crate) fn parse(sled_k: &[u8], sled_v: &[u8]) -> Self {
Self {
- key: sled_k.to_vec(),
+ tombstone_timestamp: u64::from_be_bytes(sled_k[0..8].try_into().unwrap()),
+ key: sled_k[8..].to_vec(),
value_hash: Hash::try_from(sled_v).unwrap(),
value: None,
}
@@ -336,7 +362,7 @@ impl GcTodoEntry {
/// Saves the GcTodoEntry in the gc_todo tree
pub(crate) fn save(&self, gc_todo_tree: &sled::Tree) -> Result<(), Error> {
- gc_todo_tree.insert(&self.key[..], self.value_hash.as_slice())?;
+ gc_todo_tree.insert(self.todo_table_key(), self.value_hash.as_slice())?;
Ok(())
}
@@ -347,10 +373,22 @@ impl GcTodoEntry {
/// what we have to do is still the same
pub(crate) fn remove_if_equal(&self, gc_todo_tree: &sled::Tree) -> Result<(), Error> {
let _ = gc_todo_tree.compare_and_swap::<_, _, Vec<u8>>(
- &self.key[..],
+ &self.todo_table_key()[..],
Some(self.value_hash),
None,
)?;
Ok(())
}
+
+ fn todo_table_key(&self) -> Vec<u8> {
+ [
+ &u64::to_be_bytes(self.tombstone_timestamp)[..],
+ &self.key[..],
+ ]
+ .concat()
+ }
+
+ fn deletion_time(&self) -> u64 {
+ self.tombstone_timestamp + TABLE_GC_DELAY.as_millis() as u64
+ }
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-10 11:13:56 +0000