From 4a0c572440c7df2f56a6f5fb5aec9e366d522edb Mon Sep 17 00:00:00 2001
From: leveldb Team <no-reply@google.com>
Date: Fri, 6 Mar 2026 21:29:47 +0000
Subject: [PATCH] Fix TEST_CompactMemTable deadlock

This CL ensures that CompactRange doesn't get stuck on waiting on background_work_finished_signal_ during shutdown.
While background_work_finished_signal_ may be in fact signaled, CompactMemTable() will never run, not giving opportunity for workers blocked in TEST_CompactMemTable to exit the loop.
We suspect this contributes to b/370844779; while the hang was mitigated
by limiting concurrency to 1 worker (which avoids filling the thread pool with
blocked workers), this issue can still happen and will block 1 worker during
shutdown.

PiperOrigin-RevId: 879794057
---
 db/db_impl.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/db/db_impl.cc b/db/db_impl.cc
index f96d245..ce4ef82 100644
--- a/db/db_impl.cc
+++ b/db/db_impl.cc
@@ -646,7 +646,8 @@ Status DBImpl::TEST_CompactMemTable() {
   if (s.ok()) {
     // Wait until the compaction completes
     MutexLock l(&mutex_);
-    while (imm_ != nullptr && bg_error_.ok()) {
+    while (imm_ != nullptr && bg_error_.ok() &&
+           !shutting_down_.load(std::memory_order_acquire)) {
       background_work_finished_signal_.Wait();
     }
     if (imm_ != nullptr) {