perf: don't execute empty blocks (#2064)

Co-authored-by: Georgios Konstantopoulos <me@gakonst.com>

crates/executor/src/executor.rs

@@ -381,6 +381,10 @@ where
         total_difficulty: U256,
         senders: Option<Vec<Address>>,
     ) -> Result<(PostState, u64), Error> {
+        // perf: do not execute empty blocks
+        if block.body.is_empty() {
+            return Ok((PostState::default(), 0))
+        }
         let senders = self.recover_senders(&block.body, senders)?;
 
         self.init_env(&block.header, total_difficulty);
@@ -447,12 +451,14 @@ where
             return Err(Error::BlockGasUsed { got: cumulative_gas_used, expected: block.gas_used })
         }
 
+        // Add block rewards
         let balance_increments = self.post_block_balance_increments(block, total_difficulty)?;
         let mut includes_block_transition = !balance_increments.is_empty();
         for (address, increment) in balance_increments.into_iter() {
             self.increment_account_balance(address, increment, &mut post_state)?;
         }
 
+        // Perform DAO irregular state change
         if self.chain_spec.fork(Hardfork::Dao).transitions_at_block(block.number) {
             includes_block_transition = true;
             self.apply_dao_fork_changes(&mut post_state)?;
@@ -461,7 +467,6 @@ where
         if includes_block_transition {
             post_state.finish_transition();
         }
-
         Ok(post_state)
     }
 
@@ -473,6 +478,10 @@ where
     ) -> Result<PostState, Error> {
         let post_state = self.execute(block, total_difficulty, senders)?;
 
+        // TODO Before Byzantium, receipts contained state root that would mean that expensive
+        // operation as hashing that is needed for state root got calculated in every
+        // transaction This was replaced with is_success flag.
+        // See more about EIP here: https://eips.ethereum.org/EIPS/eip-658
         if self.chain_spec.fork(Hardfork::Byzantium).active_at_block(block.header.number) {
             verify_receipt(
                 block.header.receipts_root,
@@ -481,11 +490,6 @@ where
             )?;
         }
 
-        // TODO Before Byzantium, receipts contained state root that would mean that expensive
-        // operation as hashing that is needed for state root got calculated in every
-        // transaction This was replaced with is_success flag.
-        // See more about EIP here: https://eips.ethereum.org/EIPS/eip-658
-
         Ok(post_state)
     }
 }

crates/stages/src/stages/execution.rs

@@ -16,6 +16,7 @@ use reth_primitives::{Address, Block, U256};
 use reth_provider::{
     post_state::PostState, BlockExecutor, ExecutorFactory, LatestStateProviderRef, Transaction,
 };
+use std::time::Instant;
 use tracing::*;
 
 /// The [`StageId`] of the execution stage.
@@ -182,7 +183,11 @@ impl<EF: ExecutorFactory> ExecutionStage<EF> {
 
         // put execution results to database
         let first_transition_id = tx.get_block_transition(last_block)?;
+
+        let start = Instant::now();
+        trace!(target: "sync::stages::execution", changes = state.changes().len(), accounts = state.accounts().len(), "Writing updated state to database");
         state.write_to_db(&**tx, first_transition_id)?;
+        trace!(target: "sync::stages::execution", took = ?Instant::now().duration_since(start), "Wrote state");
 
         let done = !capped;
         info!(target: "sync::stages::execution", stage_progress = end_block, done, "Sync iteration finished");