Simplify a little the cache when possible.

CLI.md

@@ -108,7 +108,7 @@ A Byzantine-fault tolerant sidechain with low-latency finality and high throughp
 * `--max-stream-queries <MAX_STREAM_QUERIES>` — The maximal number of simultaneous stream queries to the database
 
   Default value: `10`
-* `--max-cache-size <MAX_CACHE_SIZE>` — The maximal size of the storage cache
+* `--max-cache-size <MAX_CACHE_SIZE>` — The maximal size of the storage cache, in bytes
 
   Default value: `10000000`
 * `--max-cache-entries <MAX_CACHE_ENTRIES>` — The maximal number of entries in the storage cache

linera-views/src/backends/lru_caching.rs

@@ -492,7 +492,6 @@ impl LruPrefixCache {
             // which is counter productive
             return;
         }
-        let full_prefix = (key_prefix.clone(), CacheEntry::Find);
         let keys = self
             .map_find
             .range(get_interval(key_prefix.clone()))
@@ -503,6 +502,19 @@ impl LruPrefixCache {
             let full_key = (key, CacheEntry::Find);
             self.remove_from_queue(&full_key);
         }
+        if let FindCacheEntry::KeyValues(_) = cache_entry {
+            let keys = self
+                .map_value
+                .range(get_interval(key_prefix.clone()))
+                .map(|(x,_)| x.clone())
+                .collect::<Vec<_>>();
+            for key in keys {
+                self.map_value.remove(&key);
+                let full_key = (key, CacheEntry::Value);
+                self.remove_from_queue(&full_key);
+            }
+        }
+        let full_prefix = (key_prefix.clone(), CacheEntry::Find);
         match self.map_find.entry(key_prefix.clone()) {
             btree_map::Entry::Occupied(mut entry) => {
                 entry.insert(cache_entry);