[Perf] Speed up the fetching of the latest block height

ledger/src/lib.rs

@@ -126,7 +126,7 @@ impl<N: Network, C: ConsensusStorage<N>> Ledger<N, C> {
         const NUM_BLOCKS: usize = 10;
         // Retrieve the latest height.
         let latest_height = ledger.current_block.read().height();
-        debug_assert_eq!(latest_height, *ledger.vm.block_store().heights().max().unwrap(), "Mismatch in latest height");
+        debug_assert_eq!(latest_height, ledger.vm.block_store().max_height().unwrap(), "Mismatch in latest height");
         // Sample random block heights.
         let block_heights: Vec<u32> =
             (0..=latest_height).choose_multiple(&mut OsRng, (latest_height as usize).min(NUM_BLOCKS));
@@ -169,15 +169,15 @@ impl<N: Network, C: ConsensusStorage<N>> Ledger<N, C> {
         };
 
         // If the block store is empty, initialize the genesis block.
-        if ledger.vm.block_store().heights().max().is_none() {
+        if ledger.vm.block_store().max_height().is_none() {
             // Add the genesis block.
             ledger.advance_to_next_block(&genesis_block)?;
         }
         lap!(timer, "Initialize genesis");
 
         // Retrieve the latest height.
         let latest_height =
-            *ledger.vm.block_store().heights().max().ok_or_else(|| anyhow!("Failed to load blocks from the ledger"))?;
+            ledger.vm.block_store().max_height().ok_or_else(|| anyhow!("Failed to load blocks from the ledger"))?;
         // Fetch the latest block.
         let block = ledger
             .get_block(latest_height)

ledger/store/src/block/mod.rs

@@ -1360,6 +1360,11 @@ impl<N: Network, B: BlockStorage<N>> BlockStore<N, B> {
         self.storage.id_map().keys_confirmed()
     }
 
+    /// Returns the height of the latest block in the storage.
+    pub fn max_height(&self) -> Option<u32> {
+        self.storage.id_map().len_confirmed().checked_sub(1)?.try_into().ok()
+    }
+
     /// Returns an iterator over the block hashes, for all blocks in `self`.
     pub fn hashes(&self) -> impl '_ + Iterator<Item = Cow<'_, N::BlockHash>> {
         self.storage.reverse_id_map().keys_confirmed()

synthesizer/src/vm/mod.rs

@@ -481,7 +481,6 @@ pub(crate) mod test_helpers {
 
     use indexmap::IndexMap;
     use once_cell::sync::OnceCell;
-    use std::borrow::Borrow;
     #[cfg(feature = "rocks")]
     use std::path::Path;
     use synthesizer_snark::VerifyingKey;
@@ -763,8 +762,7 @@ function compute:
         rng: &mut R,
     ) -> Result<Block<MainnetV0>> {
         // Get the most recent block.
-        let block_hash =
-            vm.block_store().get_block_hash(*vm.block_store().heights().max().unwrap().borrow()).unwrap().unwrap();
+        let block_hash = vm.block_store().get_block_hash(vm.block_store().max_height().unwrap()).unwrap().unwrap();
         let previous_block = vm.block_store().get_block(&block_hash).unwrap().unwrap();
 
         // Construct the new block header.

synthesizer/tests/test_vm_execute_and_finalize.rs

@@ -38,7 +38,6 @@ use anyhow::Result;
 use console::account::Address;
 use indexmap::IndexMap;
 use rayon::prelude::*;
-use std::borrow::Borrow;
 use utilities::*;
 
 #[test]
@@ -457,8 +456,7 @@ fn construct_next_block<C: ConsensusStorage<CurrentNetwork>, R: Rng + CryptoRng>
     rng: &mut R,
 ) -> Result<Block<CurrentNetwork>> {
     // Get the most recent block.
-    let block_hash =
-        vm.block_store().get_block_hash(*vm.block_store().heights().max().unwrap().borrow()).unwrap().unwrap();
+    let block_hash = vm.block_store().get_block_hash(vm.block_store().max_height().unwrap()).unwrap().unwrap();
     let previous_block = vm.block_store().get_block(&block_hash).unwrap().unwrap();
 
     // Construct the metadata associated with the block.
@@ -523,7 +521,7 @@ fn construct_finalize_global_state<C: ConsensusStorage<CurrentNetwork>>(
     vm: &VM<CurrentNetwork, C>,
 ) -> FinalizeGlobalState {
     // Retrieve the latest block.
-    let block_height = *vm.block_store().heights().max().unwrap().clone();
+    let block_height = vm.block_store().max_height().unwrap();
     let latest_block_hash = vm.block_store().get_block_hash(block_height).unwrap().unwrap();
     let latest_block = vm.block_store().get_block(&latest_block_hash).unwrap().unwrap();
     // Retrieve the latest round.