Use rocksdb Hyperclock cache instead of LRU cache

flake.nix

@@ -107,7 +107,7 @@
             ELEMENTSD_EXEC = "${pkgs.elementsd}/bin/elementsd";
             BITCOIND_EXEC = "${pkgs.bitcoind}/bin/bitcoind";
 
-            buildInputs = with pkgs; [ heaptrack rocksdb.tools];
+            buildInputs = with pkgs; [ rocksdb.tools ];
           };
         }
       );

src/server/mod.rs

@@ -109,7 +109,7 @@ pub struct Arguments {
 
     // TODO make rocksdb parameter conditional on feature db
     /// RocksDB point lookup cache size in MB for UTXO and HISTORY column families
-    #[arg(env, long, default_value = "64")]
+    #[arg(env, long, default_value = "128")]
     pub shared_db_cache_mb: u64,
 
     /// Enable RocksDB statistics collection for detailed metrics

src/store/db.rs

@@ -91,9 +91,12 @@ const VEC_TX_SEEN_MIN_SIZE: usize = 34; // 32 bytes (txid) + 1 byte (height) + 1
 
 impl DBStore {
     fn create_cf_descriptors(shared_db_cache_mb: u64) -> Vec<rocksdb::ColumnFamilyDescriptor> {
-        // Create a shared LRU cache for block-based tables
-        let cache_size = (shared_db_cache_mb * 1024 * 1024) as usize; // Convert MB to bytes
-        let shared_cache = Cache::new_lru_cache(cache_size);
+        let cache_size = (shared_db_cache_mb * 1024 * 1024) as usize;
+        // HyperClockCache is lock-free, reducing mutex contention under concurrent reads.
+        // estimated_entry_charge=0 uses the auto-growing variant, which dynamically sizes
+        // its internal table — safer than a fixed estimate when caching mixed-size entries
+        // (data blocks, index blocks, filter blocks).
+        let shared_cache = Cache::new_hyper_clock_cache(cache_size, 0);
 
         COLUMN_FAMILIES
             .iter()