From 8b574712216fb4ac1a5d608060a95fec146e45d7 Mon Sep 17 00:00:00 2001
From: Michal Kucharczyk <1728078+michalkucharczyk@users.noreply.github.com>
Date: Thu, 22 Dec 2022 23:33:01 +0100
Subject: [PATCH] txpool: don't validate block transactions if the pool is
 empty (#12973)
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* txpool: don't validate block transactions if the pool is empty

Fix shall prevent from wasting the CPU during the major sync. Block
transaction don't need to be re-validated when the txpool is empty.

Fixes: #12903

* Apply suggestions from code review

Co-authored-by: Bastian Köcher <git@kchr.de>
---
 .../client/transaction-pool/src/graph/pool.rs | 23 +++++++++++++------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/substrate/client/transaction-pool/src/graph/pool.rs b/substrate/client/transaction-pool/src/graph/pool.rs
index 96cbeb9b80..8e3570d1db 100644
--- a/substrate/client/transaction-pool/src/graph/pool.rs
+++ b/substrate/client/transaction-pool/src/graph/pool.rs
@@ -271,14 +271,23 @@ impl<B: ChainApi> Pool<B> {
 				// if it's not found in the pool query the runtime at parent block
 				// to get validity info and tags that the extrinsic provides.
 				None => {
-					let validity = self
-						.validated_pool
-						.api()
-						.validate_transaction(parent, TransactionSource::InBlock, extrinsic.clone())
-						.await;
+					// Avoid validating block txs if the pool is empty
+					if !self.validated_pool.status().is_empty() {
+						let validity = self
+							.validated_pool
+							.api()
+							.validate_transaction(
+								parent,
+								TransactionSource::InBlock,
+								extrinsic.clone(),
+							)
+							.await;
 
-					if let Ok(Ok(validity)) = validity {
-						future_tags.extend(validity.provides);
+						if let Ok(Ok(validity)) = validity {
+							future_tags.extend(validity.provides);
+						}
+					} else {
+						log::trace!(target: "txpool", "txpool is empty, skipping validation for block {at:?}");
 					}
 				},
 			}