address feedback

src/vm/clarity.rs

@@ -374,13 +374,8 @@ impl ClarityInstance {
         header_db: &'a dyn HeadersDB,
         burn_state_db: &'a dyn BurnStateDB,
     ) -> ClarityReadOnlyConnection<'a> {
-        let datastore = self.datastore.begin_read_only(Some(at_block));
-
-        ClarityReadOnlyConnection {
-            datastore,
-            header_db,
-            burn_state_db,
-        }
+        self.read_only_connection_checked(at_block, header_db, burn_state_db)
+            .expect(&format!("BUG: failed to open block {}", at_block))
     }
 
     pub fn read_only_connection_checked<'a>(

testnet/stacks-node/src/neon_node.rs

@@ -740,6 +740,7 @@ fn spawn_miner_relayer(
     let mut bitcoin_controller = BitcoinRegtestController::new_dummy(config.clone());
     let mut microblock_miner_state = None;
     let mut miner_tip = None;
+    let mut last_microblock_tenure_time = 0;
 
     let _relayer_handle = thread::Builder::new().name("relayer".to_string()).spawn(move || {
         let mut did_register_key = false;
@@ -929,6 +930,12 @@ fn spawn_miner_relayer(
                     bump_processed_counter(&blocks_processed);
                 }
                 RelayerDirective::RunMicroblockTenure => {
+                    if last_microblock_tenure_time + (config.node.microblock_frequency as u128) > get_epoch_time_ms() {
+                        // only mine when necessary -- the deadline to begin hasn't passed yet
+                        continue;
+                    }
+                    last_microblock_tenure_time = get_epoch_time_ms();
+
                     debug!("Relayer: run microblock tenure");
 
                     // unconfirmed state must be consistent with the chain tip