Merge pull request #1136 from spacejam/0.34.1

Cut 0.34.1 with a new TransactionalTrees::flush method

CHANGELOG.md

@@ -1,3 +1,11 @@
+# 0.34.1
+
+## New Features
+
+* #1136 Added the `TransactionalTree::flush` method to
+  flush the underlying database after the transaction
+  commits and before the transaction returns.
+
 # 0.34
 
 ## Improvements

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "sled"
-version = "0.34.0"
+version = "0.34.1"
 authors = ["Tyler Neely <[email protected]>"]
 description = "a modern embedded database"
 license = "MIT/Apache-2.0"

src/transaction.rs

@@ -96,6 +96,7 @@ pub struct TransactionalTree {
     pub(super) tree: Tree,
     pub(super) writes: Rc<RefCell<Map<IVec, Option<IVec>>>>,
     pub(super) read_cache: Rc<RefCell<Map<IVec, Option<IVec>>>>,
+    pub(super) flush_on_commit: Rc<RefCell<bool>>,
 }
 
 /// An error type that is returned from the closure
@@ -329,6 +330,11 @@ impl TransactionalTree {
         Ok(())
     }
 
+    /// Flush the database before returning from the transaction.
+    pub fn flush(&self) {
+        *self.flush_on_commit.borrow_mut() = true;
+    }
+
     fn unstage(&self) {
         unimplemented!()
     }
@@ -352,6 +358,7 @@ impl TransactionalTree {
             tree: tree.clone(),
             writes: Default::default(),
             read_cache: Default::default(),
+            flush_on_commit: Default::default(),
         }
     }
 }
@@ -392,6 +399,22 @@ impl TransactionalTrees {
         // recovered atomically
         peg.seal_batch()
     }
+
+    fn flush_if_configured(&self) -> Result<()> {
+        let mut should_flush = None;
+
+        for tree in &self.inner {
+            if *tree.flush_on_commit.borrow() {
+                should_flush = Some(tree);
+                break;
+            }
+        }
+
+        if let Some(tree) = should_flush {
+            tree.tree.flush()?;
+        }
+        Ok(())
+    }
 }
 
 /// A simple constructor for `Err(TransactionError::Abort(_))`
@@ -427,7 +450,7 @@ pub trait Transactional<E = ()> {
             let view = Self::view_overlay(&tt);
 
             // NB locks must exist until this function returns.
-            let _locks = if let Ok(l) = tt.stage() {
+            let locks = if let Ok(l) = tt.stage() {
                 l
             } else {
                 tt.unstage();
@@ -442,6 +465,8 @@ pub trait Transactional<E = ()> {
                 Ok(r) => {
                     let guard = pin();
                     tt.commit(&guard)?;
+                    drop(locks);
+                    tt.flush_if_configured()?;
                     return Ok(r);
                 }
                 Err(ConflictableTransactionError::Abort(e)) => {

tests/test_tree.rs

@@ -504,6 +504,21 @@ fn concurrent_tree_transactions() -> TransactionResult<()> {
     Ok(())
 }
 
+#[test]
+fn tree_flush_in_transaction() {
+    let config = sled::Config::new().temporary(true);
+    let db = config.open().unwrap();
+    let tree = db.open_tree(b"a").unwrap();
+
+    tree.transaction::<_, _, sled::transaction::TransactionError>(|tree| {
+        tree.insert(b"k1", b"cats")?;
+        tree.insert(b"k2", b"dogs")?;
+        tree.flush();
+        Ok(())
+    })
+    .unwrap();
+}
+
 #[test]
 fn incorrect_multiple_db_transactions() -> TransactionResult<()> {
     common::setup_logger();