Resize sync buffers

- The DB buffer should be smaller than the body request buffer,
otherwise we'll never know if we have hit our maximum I/O throughput

trinity/sync/full/chain.py

@@ -62,6 +62,7 @@
 from trinity.sync.common.peers import WaitingPeers
 from trinity.sync.full.constants import (
     HEADER_QUEUE_SIZE_TARGET,
+    BLOCK_QUEUE_SIZE_TARGET,
 )
 from trinity._utils.datastructures import (
     MissingDependency,
@@ -82,7 +83,7 @@
 ]
 
 # How big should the pending request queue get, as a multiple of the largest request size
-REQUEST_BUFFER_MULTIPLIER = 8
+REQUEST_BUFFER_MULTIPLIER = 16
 
 
 class BaseBodyChainSyncer(BaseService, PeerSubscriber):
@@ -583,7 +584,7 @@ async def _persist_ready_blocks(self) -> None:
         while self.is_operational:
             # This tracker waits for all prerequisites to be complete, and returns headers in
             # order, so that each header's parent is already persisted.
-            get_completed_coro = self._block_persist_tracker.ready_tasks(HEADER_QUEUE_SIZE_TARGET)
+            get_completed_coro = self._block_persist_tracker.ready_tasks(BLOCK_QUEUE_SIZE_TARGET)
             completed_headers = await self.wait(get_completed_coro)
 
             if self._block_persist_tracker.has_ready_tasks():

trinity/sync/full/constants.py

@@ -11,7 +11,8 @@
 # BUFFER_SECONDS = 30
 #   (this should allow plenty of time for peers to fill in the buffer during db writes)
 #
-# MARGIN = 10
-#   (better to have a buffer that's too big than to artificially constrain performance)
-#
-HEADER_QUEUE_SIZE_TARGET = 60000
+HEADER_QUEUE_SIZE_TARGET = 6000
+
+# How many blocks to persist at a time
+# Only need a few seconds of buffer on the DB write side.
+BLOCK_QUEUE_SIZE_TARGET = 1000