From 814c6a899deb05a6b343629ffbf81058dbc5caed Mon Sep 17 00:00:00 2001
From: Robert Schulze <robert@clickhouse.com>
Date: Mon, 2 Jan 2023 11:08:49 +0000
Subject: [PATCH] Simplify the code a bit

---
 src/Interpreters/Cache/QueryResultCache.cpp      | 16 ++++++++--------
 src/Interpreters/Cache/QueryResultCache.h        |  4 +---
 .../System/StorageSystemQueryResultCache.cpp     |  4 ++--
 3 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/src/Interpreters/Cache/QueryResultCache.cpp b/src/Interpreters/Cache/QueryResultCache.cpp
index 07c79ac61cc..ea82f317878 100644
--- a/src/Interpreters/Cache/QueryResultCache.cpp
+++ b/src/Interpreters/Cache/QueryResultCache.cpp
@@ -180,8 +180,8 @@ try
         return res;
     };
 
-    auto result = std::make_shared<Chunk>(to_single_chunk(partial_results));
-    new_entry_size_in_bytes = result->allocatedBytes(); // updated because compression potentially affects the size of the single chunk vs the aggregate size of individual chunks
+    auto result = to_single_chunk(partial_results);
+    new_entry_size_in_bytes = result.allocatedBytes(); // updated because compression potentially affects the size of the single chunk vs the aggregate size of individual chunks
 
     std::lock_guard lock(mutex);
 
@@ -200,7 +200,7 @@ try
         for (auto it = cache.begin(); it != cache.end();)
             if (is_stale(it->first))
             {
-                cache_size_in_bytes -= it->second->allocatedBytes();
+                cache_size_in_bytes -= it->second.allocatedBytes();
                 it = cache.erase(it);
                 ++removed_items;
             }
@@ -212,13 +212,13 @@ try
     /// Insert or replace if enough space
     if (sufficient_space_in_cache())
     {
-        cache_size_in_bytes += result->allocatedBytes();
+        cache_size_in_bytes += result.allocatedBytes();
         if (auto it = cache.find(key); it != cache.end())
-            cache_size_in_bytes -= it->second->allocatedBytes(); /// key replacement
+            cache_size_in_bytes -= it->second.allocatedBytes(); /// key replacement
 
         /// cache[key] = result; /// does no replacement for unclear reasons
         cache.erase(key);
-        cache[key] = result;
+        cache[key] = std::move(result);
 
         LOG_DEBUG(&Poco::Logger::get("QueryResultCache"), "Stored result of query {}", key.queryStringFromAst());
     }
@@ -260,14 +260,14 @@ QueryResultCache::Reader::Reader(const Cache & cache_, const Key & key, size_t &
     if (it->first.expires_at < std::chrono::system_clock::now())
     {
         Cache & cache_rw = const_cast<Cache &>(cache_);
-        cache_size_in_bytes_ -= it->second->allocatedBytes();
+        cache_size_in_bytes_ -= it->second.allocatedBytes();
         cache_rw.erase(it);
         LOG_DEBUG(&Poco::Logger::get("QueryResultCache"), "Stale entry found and removed for query {}", key.queryStringFromAst());
         return;
     }
 
     LOG_DEBUG(&Poco::Logger::get("QueryResultCache"), "Entry found for query {}", key.queryStringFromAst());
-    pipe = Pipe(std::make_shared<SourceFromSingleChunk>(key.header, it->second->clone()));
+    pipe = Pipe(std::make_shared<SourceFromSingleChunk>(key.header, it->second.clone()));
 }
 
 bool QueryResultCache::Reader::hasCacheEntryForKey() const
diff --git a/src/Interpreters/Cache/QueryResultCache.h b/src/Interpreters/Cache/QueryResultCache.h
index 1b8f6d28cf4..fe3981c0dfd 100644
--- a/src/Interpreters/Cache/QueryResultCache.h
+++ b/src/Interpreters/Cache/QueryResultCache.h
@@ -66,10 +66,8 @@ private:
         size_t operator()(const Key & key) const;
     };
 
-    using Entry = std::shared_ptr<Chunk>;
-
     /// query --> query result
-    using Cache = std::unordered_map<Key, Entry, KeyHasher>;
+    using Cache = std::unordered_map<Key, Chunk, KeyHasher>;
 
     /// query --> query execution count
     using TimesExecutedMap = std::unordered_map<Key, size_t, KeyHasher>;
diff --git a/src/Storages/System/StorageSystemQueryResultCache.cpp b/src/Storages/System/StorageSystemQueryResultCache.cpp
index 3312475ded5..061fccc7539 100644
--- a/src/Storages/System/StorageSystemQueryResultCache.cpp
+++ b/src/Storages/System/StorageSystemQueryResultCache.cpp
@@ -38,7 +38,7 @@ void StorageSystemQueryResultCache::fillData(MutableColumns & res_columns, Conte
 
     std::lock_guard lock(query_result_cache->mutex);
 
-    for (const auto & [key, entry] : query_result_cache->cache)
+    for (const auto & [key, result] : query_result_cache->cache)
     {
         /// Showing other user's queries is considered a security risk
         if (key.username.has_value() && key.username != username)
@@ -50,7 +50,7 @@ void StorageSystemQueryResultCache::fillData(MutableColumns & res_columns, Conte
         res_columns[3]->insert(key.expires_at < std::chrono::system_clock::now());
         res_columns[4]->insert(!key.username.has_value());
         res_columns[5]->insert(key.partition_key);
-        res_columns[6]->insert(entry->allocatedBytes());
+        res_columns[6]->insert(result.allocatedBytes());
     }
 }