Minor refactoring

dbms/src/Common/RWLock.cpp

@@ -1,4 +1,4 @@
-#include "RWLockFIFO.h"
+#include "RWLock.h"
 #include <Common/Stopwatch.h>
 #include <Common/Exception.h>
 #include <Poco/Ext/ThreadNumber.h>
@@ -33,15 +33,15 @@ namespace ErrorCodes
 }
 
 
-class RWLockFIFO::LockHandlerImpl
+class RWLockImpl::LockHandlerImpl
 {
-    RWLockFIFOPtr parent;
+    RWLock parent;
     GroupsContainer::iterator it_group;
     ClientsContainer::iterator it_client;
     ThreadToHandler::iterator it_handler;
     CurrentMetrics::Increment active_client_increment;
 
-    LockHandlerImpl(RWLockFIFOPtr && parent, GroupsContainer::iterator it_group, ClientsContainer::iterator it_client);
+    LockHandlerImpl(RWLock && parent, GroupsContainer::iterator it_group, ClientsContainer::iterator it_client);
 
 public:
 
@@ -49,11 +49,11 @@ public:
 
     ~LockHandlerImpl();
 
-    friend class RWLockFIFO;
+    friend class RWLockImpl;
 };
 
 
-RWLockFIFO::LockHandler RWLockFIFO::getLock(RWLockFIFO::Type type, RWLockFIFO::Client client)
+RWLockImpl::LockHandler RWLockImpl::getLock(RWLockImpl::Type type, RWLockImpl::Client client)
 {
     Stopwatch watch(CLOCK_MONOTONIC_COARSE);
     CurrentMetrics::Increment waiting_client_increment((type == Read) ? CurrentMetrics::RWLockWaitingReaders
@@ -142,24 +142,7 @@ RWLockFIFO::LockHandler RWLockFIFO::getLock(RWLockFIFO::Type type, RWLockFIFO::C
 }
 
 
-RWLockFIFO::Clients RWLockFIFO::getClientsInTheQueue() const
-{
-    std::unique_lock<std::mutex> lock(mutex);
-
-    Clients res;
-    for (const auto & group : queue)
-    {
-        for (const auto & client : group.clients)
-        {
-            res.emplace_back(client);
-        }
-    }
-
-    return res;
-}
-
-
-RWLockFIFO::LockHandlerImpl::~LockHandlerImpl()
+RWLockImpl::LockHandlerImpl::~LockHandlerImpl()
 {
     std::unique_lock<std::mutex> lock(parent->mutex);
 
@@ -183,10 +166,10 @@ RWLockFIFO::LockHandlerImpl::~LockHandlerImpl()
 }
 
 
-RWLockFIFO::LockHandlerImpl::LockHandlerImpl(RWLockFIFOPtr && parent, RWLockFIFO::GroupsContainer::iterator it_group,
-                                             RWLockFIFO::ClientsContainer::iterator it_client)
+RWLockImpl::LockHandlerImpl::LockHandlerImpl(RWLock && parent, RWLockImpl::GroupsContainer::iterator it_group,
+                                             RWLockImpl::ClientsContainer::iterator it_client)
     : parent{std::move(parent)}, it_group{it_group}, it_client{it_client},
-      active_client_increment{(it_client->type == RWLockFIFO::Read) ? CurrentMetrics::RWLockActiveReaders
+      active_client_increment{(it_client->type == RWLockImpl::Read) ? CurrentMetrics::RWLockActiveReaders
                                                                     : CurrentMetrics::RWLockActiveWriters}
 {}
 

dbms/src/Common/RWLock.h

@@ -12,19 +12,19 @@
 namespace DB
 {
 
-class RWLockFIFO;
-using RWLockFIFOPtr = std::shared_ptr<RWLockFIFO>;
+class RWLockImpl;
+using RWLock = std::shared_ptr<RWLockImpl>;
 
 
 /// Implements shared lock with FIFO service
-/// You could call it recursively (several calls from the same thread) in Read mode
-class RWLockFIFO : public std::enable_shared_from_this<RWLockFIFO>
+/// Can be acquired recursively (several calls from the same thread) in Read mode
+class RWLockImpl : public std::enable_shared_from_this<RWLockImpl>
 {
 public:
     enum Type
     {
         Read,
-        Write
+        Write,
     };
 
 private:
@@ -44,11 +44,7 @@ private:
     };
 
 public:
-    static RWLockFIFOPtr create()
-    {
-        return RWLockFIFOPtr(new RWLockFIFO);
-    }
-
+    static RWLock create() { return RWLock(new RWLockImpl); }
 
     /// Just use LockHandler::reset() to release the lock
     class LockHandlerImpl;
@@ -58,19 +54,10 @@ public:
 
     /// Waits in the queue and returns appropriate lock
     LockHandler getLock(Type type, Client client = Client{});
-
-    LockHandler getLock(Type type, const std::string & who)
-    {
-        return getLock(type, Client(who));
-    }
-
-    using Clients = std::vector<Client>;
-
-    /// Returns list of executing and waiting clients
-    Clients getClientsInTheQueue() const;
+    LockHandler getLock(Type type, const std::string & who) { return getLock(type, Client(who)); }
 
 private:
-    RWLockFIFO() = default;
+    RWLockImpl() = default;
 
     struct Group;
     using GroupsContainer = std::list<Group>;

dbms/src/Common/tests/gtest_rw_lock_fifo.cpp.cpp

@@ -4,7 +4,7 @@
 #endif
 #include <gtest/gtest.h>
 
-#include <Common/RWLockFIFO.h>
+#include <Common/RWLock.h>
 #include <Common/Stopwatch.h>
 #include <common/Types.h>
 #include <common/ThreadPool.h>
@@ -18,7 +18,7 @@
 using namespace DB;
 
 
-TEST(Common, RWLockFIFO_1)
+TEST(Common, RWLock_1)
 {
     constexpr int cycles = 1000;
     const std::vector<size_t> pool_sizes{1, 2, 4, 8};
@@ -26,7 +26,7 @@ TEST(Common, RWLockFIFO_1)
     static std::atomic<int> readers{0};
     static std::atomic<int> writers{0};
 
-    static auto fifo_lock = RWLockFIFO::create();
+    static auto fifo_lock = RWLockImpl::create();
 
     static thread_local std::random_device rd;
     static thread_local pcg64 gen(rd());
@@ -35,12 +35,12 @@ TEST(Common, RWLockFIFO_1)
     {
         for (int i = 0; i < cycles; ++i)
         {
-            auto type = (std::uniform_int_distribution<>(0, 9)(gen) >= round) ? RWLockFIFO::Read : RWLockFIFO::Write;
+            auto type = (std::uniform_int_distribution<>(0, 9)(gen) >= round) ? RWLockImpl::Read : RWLockImpl::Write;
             auto sleep_for = std::chrono::duration<int, std::micro>(std::uniform_int_distribution<>(1, 100)(gen));
 
             auto lock = fifo_lock->getLock(type, "RW");
 
-            if (type == RWLockFIFO::Write)
+            if (type == RWLockImpl::Write)
             {
                 ++writers;
 
@@ -85,11 +85,11 @@ TEST(Common, RWLockFIFO_1)
     }
 }
 
-TEST(Common, RWLockFIFO_Recursive)
+TEST(Common, RWLock_Recursive)
 {
     constexpr auto cycles = 10000;
 
-    static auto fifo_lock = RWLockFIFO::create();
+    static auto fifo_lock = RWLockImpl::create();
 
     static thread_local std::random_device rd;
     static thread_local pcg64 gen(rd());
@@ -98,7 +98,7 @@ TEST(Common, RWLockFIFO_Recursive)
     {
         for (int i = 0; i < 2 * cycles; ++i)
         {
-            auto lock = fifo_lock->getLock(RWLockFIFO::Write);
+            auto lock = fifo_lock->getLock(RWLockImpl::Write);
 
             auto sleep_for = std::chrono::duration<int, std::micro>(std::uniform_int_distribution<>(1, 100)(gen));
             std::this_thread::sleep_for(sleep_for);
@@ -109,17 +109,17 @@ TEST(Common, RWLockFIFO_Recursive)
     {
         for (int i = 0; i < cycles; ++i)
         {
-            auto lock1 = fifo_lock->getLock(RWLockFIFO::Read);
+            auto lock1 = fifo_lock->getLock(RWLockImpl::Read);
 
             auto sleep_for = std::chrono::duration<int, std::micro>(std::uniform_int_distribution<>(1, 100)(gen));
             std::this_thread::sleep_for(sleep_for);
 
-            auto lock2 = fifo_lock->getLock(RWLockFIFO::Read);
+            auto lock2 = fifo_lock->getLock(RWLockImpl::Read);
 
-            EXPECT_ANY_THROW({fifo_lock->getLock(RWLockFIFO::Write);});
+            EXPECT_ANY_THROW({fifo_lock->getLock(RWLockImpl::Write);});
         }
 
-        fifo_lock->getLock(RWLockFIFO::Write);
+        fifo_lock->getLock(RWLockImpl::Write);
     });
 
     t1.join();
@@ -127,12 +127,12 @@ TEST(Common, RWLockFIFO_Recursive)
 }
 
 
-TEST(Common, RWLockFIFO_PerfTest_Readers)
+TEST(Common, RWLock_PerfTest_Readers)
 {
     constexpr int cycles = 100000; // 100k
     const std::vector<size_t> pool_sizes{1, 2, 4, 8};
 
-    static auto fifo_lock = RWLockFIFO::create();
+    static auto fifo_lock = RWLockImpl::create();
 
     for (auto pool_size : pool_sizes)
     {
@@ -142,7 +142,7 @@ TEST(Common, RWLockFIFO_PerfTest_Readers)
             {
                 for (auto i = 0; i < cycles; ++i)
                 {
-                    auto lock = fifo_lock->getLock(RWLockFIFO::Read);
+                    auto lock = fifo_lock->getLock(RWLockImpl::Read);
                 }
             };
 

dbms/src/Storages/IStorage.cpp

@@ -8,9 +8,9 @@ TableStructureReadLock::TableStructureReadLock(StoragePtr storage_, bool lock_st
     : storage(storage_)
 {
     if (lock_data)
-        data_lock = storage->data_lock->getLock(RWLockFIFO::Read, who);
+        data_lock = storage->data_lock->getLock(RWLockImpl::Read, who);
     if (lock_structure)
-        structure_lock = storage->structure_lock->getLock(RWLockFIFO::Read, who);
+        structure_lock = storage->structure_lock->getLock(RWLockImpl::Read, who);
 }
 
 }

dbms/src/Storages/IStorage.h

@@ -2,7 +2,7 @@
 
 #include <Core/Names.h>
 #include <Common/Exception.h>
-#include <Common/RWLockFIFO.h>
+#include <Common/RWLock.h>
 #include <Core/Names.h>
 #include <Core/QueryProcessingStage.h>
 #include <Databases/IDatabase.h>
@@ -28,9 +28,6 @@ class Context;
 class IBlockInputStream;
 class IBlockOutputStream;
 
-class RWLockFIFO;
-using RWLockFIFOPtr = std::shared_ptr<RWLockFIFO>;
-
 using StorageActionBlockType = size_t;
 
 using BlockOutputStreamPtr = std::shared_ptr<IBlockOutputStream>;
@@ -64,8 +61,8 @@ private:
 
     StoragePtr storage;
     /// Order is important.
-    RWLockFIFO::LockHandler data_lock;
-    RWLockFIFO::LockHandler structure_lock;
+    RWLockImpl::LockHandler data_lock;
+    RWLockImpl::LockHandler structure_lock;
 
 public:
     TableStructureReadLock(StoragePtr storage_, bool lock_structure, bool lock_data, const std::string & who);
@@ -75,8 +72,8 @@ public:
 using TableStructureReadLockPtr = std::shared_ptr<TableStructureReadLock>;
 using TableStructureReadLocks = std::vector<TableStructureReadLockPtr>;
 
-using TableStructureWriteLock = RWLockFIFO::LockHandler;
-using TableDataWriteLock = RWLockFIFO::LockHandler;
+using TableStructureWriteLock = RWLockImpl::LockHandler;
+using TableDataWriteLock = RWLockImpl::LockHandler;
 using TableFullWriteLock = std::pair<TableDataWriteLock, TableStructureWriteLock>;
 
 
@@ -148,7 +145,7 @@ public:
       */
     TableDataWriteLock lockDataForAlter(const std::string & who = "Alter")
     {
-        auto res = data_lock->getLock(RWLockFIFO::Write, who);
+        auto res = data_lock->getLock(RWLockImpl::Write, who);
         if (is_dropped)
             throw Exception("Table is dropped", ErrorCodes::TABLE_IS_DROPPED);
         return res;
@@ -156,7 +153,7 @@ public:
 
     TableStructureWriteLock lockStructureForAlter(const std::string & who = "Alter")
     {
-        auto res = structure_lock->getLock(RWLockFIFO::Write, who);
+        auto res = structure_lock->getLock(RWLockImpl::Write, who);
         if (is_dropped)
             throw Exception("Table is dropped", ErrorCodes::TABLE_IS_DROPPED);
         return res;
@@ -367,7 +364,7 @@ private:
       *  2) all changes to the data after releasing the lock will be based on the structure of the table at the time after the lock was released.
       * You need to take for read for the entire time of the operation that changes the data.
       */
-    mutable RWLockFIFOPtr data_lock = RWLockFIFO::create();
+    mutable RWLock data_lock = RWLockImpl::create();
 
     /** Lock for multiple columns and path to table. It is taken for write at RENAME, ALTER (for ALTER MODIFY for a while) and DROP.
       * It is taken for read for the whole time of SELECT, INSERT and merge parts (for MergeTree).
@@ -376,7 +373,7 @@ private:
       * That is, if this lock is taken for write, you should not worry about `parts_writing_lock`.
       * parts_writing_lock is only needed for cases when you do not want to take `table_structure_lock` for long operations (ALTER MODIFY).
       */
-    mutable RWLockFIFOPtr structure_lock = RWLockFIFO::create();
+    mutable RWLock structure_lock = RWLockImpl::create();
 };
 
 /// table name -> table