From c1de51dc5bcb44024953efe7b6e78b1f424dfca2 Mon Sep 17 00:00:00 2001
From: Alexey Milovidov <milovidov@yandex-team.ru>
Date: Tue, 20 Aug 2019 22:53:27 +0300
Subject: [PATCH] Better code

---
 .../Storages/System/StorageSystemNumbers.cpp  | 23 +++++++++++--------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/dbms/src/Storages/System/StorageSystemNumbers.cpp b/dbms/src/Storages/System/StorageSystemNumbers.cpp
index 78e25e0c375..2afe2a7c018 100644
--- a/dbms/src/Storages/System/StorageSystemNumbers.cpp
+++ b/dbms/src/Storages/System/StorageSystemNumbers.cpp
@@ -5,9 +5,13 @@
 #include <DataStreams/LimitBlockInputStream.h>
 #include <Storages/System/StorageSystemNumbers.h>
 
+
 namespace DB
 {
 
+namespace
+{
+
 class NumbersBlockInputStream : public IBlockInputStream
 {
 public:
@@ -43,19 +47,19 @@ private:
 };
 
 
-struct NumbersMtState
+struct NumbersMultiThreadedState
 {
     std::atomic<UInt64> counter;
-    explicit NumbersMtState(UInt64 offset) : counter(offset) {}
+    explicit NumbersMultiThreadedState(UInt64 offset) : counter(offset) {}
 };
 
-using NumbersMtStatePtr = std::shared_ptr<NumbersMtState>;
+using NumbersMultiThreadedStatePtr = std::shared_ptr<NumbersMultiThreadedState>;
 
 class NumbersMultiThreadedBlockInputStream : public IBlockInputStream
 {
 public:
-    NumbersMultiThreadedBlockInputStream(NumbersMtStatePtr state_, UInt64 block_size_, UInt64 max_counter_)
-        : state(std::move(state_)), counter(state->counter), block_size(block_size_), max_counter(max_counter_) {}
+    NumbersMultiThreadedBlockInputStream(NumbersMultiThreadedStatePtr state_, UInt64 block_size_, UInt64 max_counter_)
+        : state(std::move(state_)), block_size(block_size_), max_counter(max_counter_) {}
 
     String getName() const override { return "NumbersMt"; }
 
@@ -70,7 +74,7 @@ protected:
         if (block_size == 0)
             return {};
 
-        UInt64 curr = counter.fetch_add(block_size, std::memory_order_acquire);
+        UInt64 curr = state->counter.fetch_add(block_size, std::memory_order_acquire);
 
         if (curr >= max_counter)
             return {};
@@ -90,13 +94,14 @@ protected:
     }
 
 private:
-    NumbersMtStatePtr state;
-    std::atomic<UInt64> & counter;
+    NumbersMultiThreadedStatePtr state;
 
     UInt64 block_size;
     UInt64 max_counter;
 };
 
+}
+
 
 StorageSystemNumbers::StorageSystemNumbers(const std::string & name_, bool multithreaded_, std::optional<UInt64> limit_, UInt64 offset_, bool even_distribution_)
     : name(name_), multithreaded(multithreaded_), even_distribution(even_distribution_), limit(limit_), offset(offset_)
@@ -127,7 +132,7 @@ BlockInputStreams StorageSystemNumbers::read(
 
     if (num_streams > 1 && !even_distribution && *limit)
     {
-        auto state = std::make_shared<NumbersMtState>(offset);
+        auto state = std::make_shared<NumbersMultiThreadedState>(offset);
         UInt64 max_counter = offset + *limit;
 
         for (size_t i = 0; i < num_streams; ++i)