diff --git a/RELEASE-NOTES b/RELEASE-NOTES
index 7c83946a2..37f3eb643 100644
--- a/RELEASE-NOTES
+++ b/RELEASE-NOTES
@@ -1,3 +1,8 @@
+version 0.9.19
+--------------
+
+- move sleep outside semaphore (issue 88)
+
 version 0.9.18
 --------------
 
diff --git a/server/block_processor.py b/server/block_processor.py
index a62badce6..9227a9600 100644
--- a/server/block_processor.py
+++ b/server/block_processor.py
@@ -89,7 +89,9 @@ async def main_loop(self, caught_up_event):
         while True:
             try:
                 with await self.semaphore:
-                    await self._prefetch_blocks(caught_up_event.is_set())
+                    fetched = await self._prefetch_blocks(caught_up_event.is_set())
+                if not fetched:
+                    await asyncio.sleep(5)
                 await self.refill_event.wait()
             except DaemonError as e:
                 self.logger.info('ignoring daemon error: {}'.format(e))
@@ -113,8 +115,7 @@ async def _prefetch_blocks(self, mempool):
             if not count:
                 self.cache.put_nowait(([], 0))
                 self.caught_up = True
-                await asyncio.sleep(5)
-                return
+                return False
 
             first = self.fetched_height + 1
             hex_hashes = await self.daemon.block_hex_hashes(first, count)
@@ -140,7 +141,7 @@ async def _prefetch_blocks(self, mempool):
             self.fetched_height += count
 
         self.refill_event.clear()
-
+        return True
 
 class ChainError(Exception):
     '''Raised on error processing blocks.'''
diff --git a/server/version.py b/server/version.py
index a0336c028..be314a970 100644
--- a/server/version.py
+++ b/server/version.py
@@ -1 +1 @@
-VERSION = "ElectrumX 0.9.18"
+VERSION = "ElectrumX 0.9.19"