perf: stop replaying empty blocks

Simply do not replay empty blocks and reap the performance rewards.
I'm careful here to still keep any upgrade blocks.

Change-Id: I601cb81cd5e241fa3ceaa315d80b33ae9f17c75d

changes/2024-06-19T182611-0400.txt

@@ -0,0 +1 @@
+Speed up read-only replay by avoiding playing empty blocks

src/Chainweb/Pact/PactService.hs

@@ -824,7 +824,10 @@ execReadOnlyReplay lowerBound maybeUpperBound = pactLabel "execReadOnlyReplay" $
                     liftIO $ writeIORef heightRef (_blockHeight bh)
                     payload <- liftIO $ fromJuste <$>
                       lookupPayloadDataWithHeight pdb (Just $ _blockHeight bh) (_blockPayloadHash bh)
-                    void $ execBlock bh (CheckablePayload payload)
+                    let isPayloadEmpty = V.null (_payloadDataTransactions payload)
+                    let isUpgradeBlock = isJust $ _chainwebVersion bhdb ^? versionUpgrades . onChain (_chainId bhdb) . ix (_blockHeight bh)
+                    unless (isPayloadEmpty && not isUpgradeBlock) $
+                      void $ execBlock bh (CheckablePayload payload)
             )
         validationFailed <- readIORef validationFailedRef
         when validationFailed $