From cfa9ba8eb1ee4832b36b8facb65497b910093f23 Mon Sep 17 00:00:00 2001
From: John Sully <john@csquare.ca>
Date: Wed, 27 Apr 2022 17:32:40 +0000
Subject: [PATCH] Ensure we are responsive during storagecache clears

---
 src/StorageCache.cpp | 18 ++++++++++++++++--
 src/StorageCache.h   |  3 ++-
 src/db.cpp           |  4 ++--
 src/lazyfree.cpp     |  2 +-
 4 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/src/StorageCache.cpp b/src/StorageCache.cpp
index 2c6dd42b9..d336e2b3d 100644
--- a/src/StorageCache.cpp
+++ b/src/StorageCache.cpp
@@ -31,11 +31,25 @@ StorageCache::~StorageCache()
         dictRelease(m_pdict);
 }
 
-void StorageCache::clear()
+void StorageCache::clear(void(callback)(void*))
 {
     std::unique_lock<fastlock> ul(m_lock);
     if (m_pdict != nullptr)
-        dictEmpty(m_pdict, nullptr);
+        dictEmpty(m_pdict, callback);
+    m_spstorage->clear();
+    m_collisionCount = 0;
+}
+
+void StorageCache::clearAsync()
+{
+    std::unique_lock<fastlock> ul(m_lock);
+    if (m_pdict != nullptr) {
+        dict *dSav = m_pdict;
+        m_pdict = dictCreate(&dbStorageCacheType, nullptr);
+        g_pserver->asyncworkqueue->AddWorkFunction([dSav]{
+            dictEmpty(dSav, nullptr);
+        });
+    }
     m_spstorage->clear();
     m_collisionCount = 0;
 }
diff --git a/src/StorageCache.h b/src/StorageCache.h
index 879b512dc..3c38450fb 100644
--- a/src/StorageCache.h
+++ b/src/StorageCache.h
@@ -38,7 +38,8 @@ public:
         return cache;
     }
 
-    void clear();
+    void clear(void(callback)(void*));
+    void clearAsync();
     void insert(sds key, const void *data, size_t cbdata, bool fOverwrite);
     void bulkInsert(char **rgkeys, size_t *rgcbkeys, char **rgvals, size_t *rgcbvals, size_t celem);
     void retrieve(sds key, IStorage::callbackSingle fn) const;
diff --git a/src/db.cpp b/src/db.cpp
index a115c887b..5b67a4198 100644
--- a/src/db.cpp
+++ b/src/db.cpp
@@ -2706,7 +2706,7 @@ void redisDbPersistentData::clear(void(callback)(void*))
     delete m_setexpire;
     m_setexpire = new (MALLOC_LOCAL) expireset();
     if (m_spstorage != nullptr)
-        m_spstorage->clear();
+        m_spstorage->clear(callback);
     dictEmpty(m_pdictTombstone,callback);
     m_pdbSnapshot = nullptr;
 }
@@ -2926,7 +2926,7 @@ bool redisDbPersistentData::processChanges(bool fSnapshot)
             if (m_fAllChanged)
             {
                 if (dictSize(m_pdict) > 0 || m_spstorage->count() > 0) { // in some cases we may have pre-sized the StorageCache's dict, and we don't want clear to ruin it
-                    m_spstorage->clear();
+                    m_spstorage->clearAsync();
                     storeDatabase();
                 }
                 m_fAllChanged = 0;
diff --git a/src/lazyfree.cpp b/src/lazyfree.cpp
index a05101f2e..fe76b2f4a 100644
--- a/src/lazyfree.cpp
+++ b/src/lazyfree.cpp
@@ -223,7 +223,7 @@ void redisDbPersistentData::emptyDbAsync() {
     m_setexpire = new (MALLOC_LOCAL) expireset();
     m_pdict = dictCreate(&dbDictType,this);
     if (m_spstorage != nullptr)
-        m_spstorage->clear();
+        m_spstorage->clearAsync();
     if (m_fTrackingChanges)
         m_fAllChanged = true;
     atomicIncr(lazyfree_objects,dictSize(oldht1));