1 files changed, 33 insertions, 0 deletions
diff --git a/log_db/src/memtable_primary.rs b/log_db/src/memtable_primary.rs
new file mode 100644
index 0000000..9d7e1e8
--- /dev/null
+++ b/log_db/src/memtable_primary.rs
@@ -0,0 +1,33 @@
+use super::common::*;
+use std::collections::BTreeMap;
+
+pub struct PrimaryMemtable {
+    /// Map of records indexed by key. Used as a shared heap of records
+    /// for all secondary memtables also. Secondary memtables store an
+    /// IndexableValue as their record value, which is used to get
+    /// the actual record from the primary memtable `records` map.
+    ///
+    /// Note: it must be invariant that all memtables (primary and secondary)
+    /// contain the same keys.
+    records: BTreeMap<IndexableValue, Record>,
+}
+
+impl PrimaryMemtable {
+    pub fn new() -> PrimaryMemtable {
+        PrimaryMemtable {
+            records: BTreeMap::new(),
+        }
+    }
+
+    pub fn set(&mut self, key: &IndexableValue, value: &Record) {
+        self.records.insert(key.clone(), value.clone());
+    }
+
+    pub fn get(&mut self, key: &IndexableValue) -> Option<&Record> {
+        self.records.get(key)
+    }
+
+    pub fn get_without_update(&self, key: &IndexableValue) -> Option<&Record> {
+        self.records.get(key)
+    }
+}