From cc4e9283dbb9e85aaa058e3f46d8fc96dfc5ab93 Mon Sep 17 00:00:00 2001
From: Tao Zhu <82401714+taozhu-chicago@users.noreply.github.com>
Date: Thu, 28 Sep 2023 09:53:17 -0500
Subject: [PATCH] reduce WARN logging to only necessary scenario (#33408)

---
 runtime/src/prioritization_fee_cache.rs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/runtime/src/prioritization_fee_cache.rs b/runtime/src/prioritization_fee_cache.rs
index e1005bd634..5f8e3d9220 100644
--- a/runtime/src/prioritization_fee_cache.rs
+++ b/runtime/src/prioritization_fee_cache.rs
@@ -322,14 +322,17 @@ impl PrioritizationFeeCache {
         // block minimum fee.
         let (result, slot_finalize_time) = measure!(
             {
+                // Only retain priority fee reported from optimistically confirmed bank
                 let pre_purge_bank_count = slot_prioritization_fee.len() as u64;
                 slot_prioritization_fee.retain(|id, _| id == bank_id);
                 let post_purge_bank_count = slot_prioritization_fee.len() as u64;
                 metrics.accumulate_total_purged_duplicated_bank_count(
                     pre_purge_bank_count.saturating_sub(post_purge_bank_count),
                 );
-                if post_purge_bank_count == 0 {
-                    warn!("Prioritization fee cache unexpected finalized on non-existing bank. slot {slot} bank id {bank_id}");
+                // It should be rare that optimistically confirmed bank had no prioritized
+                // transactions, but duplicated and unconfirmed bank had.
+                if pre_purge_bank_count > 0 && post_purge_bank_count == 0 {
+                    warn!("Finalized bank has empty prioritization fee cache. slot {slot} bank id {bank_id}");
                 }
 
                 let mut block_prioritization_fee = slot_prioritization_fee