materialized join cannot be cached

cozo-core/src/query/ra.rs

@@ -6,12 +6,9 @@
  * You can obtain one at https://mozilla.org/MPL/2.0/.
  */
 
-use std::cell::RefCell;
 use std::collections::{BTreeMap, BTreeSet};
 use std::fmt::{Debug, Formatter};
 use std::iter;
-use std::rc::Rc;
-use std::sync::atomic::{AtomicBool, Ordering};
 
 use either::{Left, Right};
 use itertools::Itertools;
@@ -474,8 +471,6 @@ impl RelAlgebra {
                     joiner,
                     to_eliminate,
                     span,
-                    mat_right_cache: RefCell::new(Default::default()),
-                    cached: Default::default(),
                 }));
                 if !remaining.is_empty() {
                     joined = RelAlgebra::Filter(FilteredRA {
@@ -521,8 +516,6 @@ impl RelAlgebra {
             },
             to_eliminate: Default::default(),
             span,
-            mat_right_cache: RefCell::new(Default::default()),
-            cached: Default::default(),
         }))
     }
     pub(crate) fn neg_join(
@@ -1531,8 +1524,6 @@ pub(crate) struct InnerJoin {
     pub(crate) joiner: Joiner,
     pub(crate) to_eliminate: BTreeSet<Symbol>,
     pub(crate) span: SourceSpan,
-    mat_right_cache: RefCell<Rc<Vec<Tuple>>>,
-    cached: AtomicBool,
 }
 
 impl InnerJoin {
@@ -1689,6 +1680,7 @@ impl InnerJoin {
         delta_rule: Option<&MagicSymbol>,
         stores: &'a BTreeMap<MagicSymbol, EpochStore>,
     ) -> Result<TupleIter<'a>> {
+        debug!("using materialized join");
         let right_bindings = self.right.bindings_after_eliminate();
         let (left_join_indices, right_join_indices) = self
             .joiner
@@ -1716,9 +1708,7 @@ impl InnerJoin {
             .sorted_by_key(|(_, b)| **b)
             .map(|(a, _)| a)
             .collect_vec();
-        let cached_data = if self.cached.load(Ordering::Relaxed) {
-            self.mat_right_cache.borrow().clone()
-        } else {
+        let cached_data = {
             let mut cache = BTreeSet::new();
             for item in self.right.iter(tx, delta_rule, stores)? {
                 match item {
@@ -1732,10 +1722,7 @@ impl InnerJoin {
                     Err(e) => return Err(e),
                 }
             }
-            let cache = cache.into_iter().collect_vec();
-            *self.mat_right_cache.borrow_mut() = Rc::new(cache);
-            self.cached.store(true, Ordering::Relaxed);
-            self.mat_right_cache.borrow().clone()
+            cache.into_iter().collect_vec()
         };
 
         let (prefix, right_idx) =
@@ -1756,7 +1743,7 @@ impl InnerJoin {
 }
 
 struct CachedMaterializedIterator<'a> {
-    materialized: Rc<Vec<Tuple>>,
+    materialized: Vec<Tuple>,
     eliminate_indices: BTreeSet<usize>,
     left_join_indices: Vec<usize>,
     right_invert_indices: Vec<usize>,

cozo-core/src/runtime/db.rs

@@ -1293,4 +1293,18 @@ mod tests {
             .rows;
         assert_eq!(res[0][0], json!(1.1))
     }
+    #[test]
+    fn test_classical() {
+        let _ = env_logger::builder().is_test(true).try_init();
+        let db = new_cozo_mem().unwrap();
+        let res = db.run_script(r#"
+parent[] <- [['joseph', 'jakob'],
+             ['jakob', 'issac'],
+             ['issac', 'abraham']]
+grandparent[gcld, gp] := parent[gcld, p], parent[p, gp]
+?[who] := grandparent[who, 'abraham']
+        "#, Default::default()).unwrap().rows;
+        println!("{:?}", res);
+        assert_eq!(res[0][0], json!("jakob"))
+    }
 }

cozo-lib-wasm/wasm-react-demo/src/App.js

@@ -224,19 +224,15 @@ function App() {
                     Please refer to the <a href="https://github.com/cozodb/cozo/">project homepage</a> for
                     more information about the Cozo database.
                 </p>
-                <h2>Not sure what to run? Click/touch <a onClick={() => {
-                    setQueryText(`love[loving, loved] <- [['alice', 'eve'], ['bob', 'alice'],
-                        ['eve', 'alice'], ['eve', 'bob'],
-                        ['eve', 'charlie'], ['charlie', 'eve'],
-                        ['david', 'george'], ['george', 'george']]
-cls[loving, loved] := love[loving, loved]
-cls[loving, loved] := cls[loving, middle], love[middle, loved]
-?[loving, loved] := cls[loving, loved]`)
-                }}>HERE</a> ...</h2>
+                <h2>Not sure what to run?</h2>
                 <p>
-                    ... and run the script, to compute the <a
-                    href="https://en.wikipedia.org/wiki/Transitive_closure">transitive closure</a> of
-                    a hypothetical love triangle.
+                    <a onClick={() => {
+                    setQueryText(`parent[] <- [['joseph', 'jakob'], 
+             ['jakob', 'issac'], 
+             ['issac', 'abraham']]
+grandparent[gcld, gp] := parent[gcld, p], parent[p, gp]
+?[who] := grandparent[who, 'abraham']`)
+                }}>Here</a> is a classical example recursive example.
                 </p>
                 <p>
                     The <a href="https://github.com/cozodb/cozo-docs/blob/main/tutorial/tutorial.ipynb">tutorial</a> contains many more examples.