diff --git a/server/block_processor.py b/server/block_processor.py
index 2b2840d..ea4265e 100644
--- a/server/block_processor.py
+++ b/server/block_processor.py
@@ -64,7 +64,7 @@ class Prefetcher(LoggedClass):
         Used in blockchain reorganisations.  This coroutine can be
         called asynchronously to the _prefetch coroutine so we must
         synchronize with a semaphore.'''
-        with await self.semaphore:
+        async with self.semaphore:
             self.fetched_height = self.bp.height
             self.refill_event.set()
 
@@ -85,7 +85,7 @@ class Prefetcher(LoggedClass):
         '''
         daemon = self.bp.daemon
         daemon_height = await daemon.height(self.bp.caught_up_event.is_set())
-        with await self.semaphore:
+        async with self.semaphore:
             while self.cache_size < self.min_cache_size:
                 # Try and catch up all blocks but limit to room in cache.
                 # Constrain fetch count to between 0 and 500 regardless;
diff --git a/server/db.py b/server/db.py
index 46aef3f..9b1cc6b 100644
--- a/server/db.py
+++ b/server/db.py
@@ -662,7 +662,7 @@ class DB(util.LoggedClass):
         while self.comp_cursor != -1:
             if self.semaphore.locked:
                 self.log_info('compact_history: waiting on semaphore...')
-            with await self.semaphore:
+            async with self.semaphore:
                 await loop.run_in_executor(None, self._compact_history, limit)
 
     def cancel_history_compaction(self):