Allocate trx_sys.mvcc at link time

trx_sys.mvcc was allocated dynamically for no good reason.

storage/innobase/handler/ha_innodb.cc

@@ -16226,7 +16226,7 @@ ha_innobase::external_lock(
 		} else if (trx->isolation_level <= TRX_ISO_READ_COMMITTED
 			   && MVCC::is_view_active(trx->read_view)) {
 			mutex_enter(&trx_sys.mutex);
-			trx_sys.mvcc->view_close(trx->read_view, true);
+			trx_sys.mvcc.view_close(trx->read_view, true);
 			mutex_exit(&trx_sys.mutex);
 		}
 	}
@@ -16894,7 +16894,7 @@ ha_innobase::store_lock(
 			/* At low transaction isolation levels we let
 			each consistent read set its own snapshot */
 			mutex_enter(&trx_sys.mutex);
-			trx_sys.mvcc->view_close(trx->read_view, true);
+			trx_sys.mvcc.view_close(trx->read_view, true);
 			mutex_enter(&trx_sys.mutex);
 		}
 	}

storage/innobase/include/read0read.h

@@ -30,18 +30,16 @@ Created 2/16/1997 Heikki Tuuri
 
 #include "read0types.h"
 
-#include <algorithm>
-
 /** The MVCC read view manager */
 class MVCC {
 public:
 	/** Constructor
 	@param size		Number of views to pre-allocate */
-	explicit MVCC(ulint size);
+	void create(ulint size);
 
 	/** Destructor.
 	Free all the views in the m_free list */
-	~MVCC();
+	void close();
 
 	/**
 	Allocate and create a view.
@@ -106,11 +104,6 @@ class MVCC {
 	@return oldest view if found or NULL */
 	inline ReadView* get_oldest_view() const;
 
-private:
-	// Prevent copying
-	MVCC(const MVCC&);
-	MVCC& operator=(const MVCC&);
-
 private:
 	typedef UT_LIST_BASE_NODE_T(ReadView) view_list_t;
 

storage/innobase/include/trx0sys.h

@@ -47,10 +47,6 @@ Created 3/26/1996 Heikki Tuuri
 
 typedef UT_LIST_BASE_NODE_T(trx_t) trx_ut_list_t;
 
-// Forward declaration
-class MVCC;
-class ReadView;
-
 /** Checks if a page address is the trx sys header page.
 @param[in]	page_id	page id
 @return true if trx sys header page */
@@ -825,6 +821,7 @@ struct trx_sys_t {
 
   MY_ALIGNED(CACHE_LINE_SIZE) trx_id_t m_max_trx_id;
 
+  bool m_initialised;
 
 public:
 	MY_ALIGNED(CACHE_LINE_SIZE)
@@ -832,7 +829,8 @@ struct trx_sys_t {
 					this structure except when noted
 					otherwise */
 
-	MVCC*		mvcc;		/*!< Multi version concurrency control
+	MY_ALIGNED(CACHE_LINE_SIZE)
+	MVCC		mvcc;		/*!< Multi version concurrency control
 					manager */
 	trx_ut_list_t	serialisation_list;
 					/*!< Ordered on trx_t::no of all the
@@ -908,7 +906,8 @@ struct trx_sys_t {
     initialisation to create().
   */
 
-  trx_sys_t(): rw_trx_ids(ut_allocator<trx_id_t>(mem_key_trx_sys_t_rw_trx_ids))
+  trx_sys_t(): m_initialised(false),
+    rw_trx_ids(ut_allocator<trx_id_t>(mem_key_trx_sys_t_rw_trx_ids))
   {}
 
 
@@ -977,6 +976,9 @@ struct trx_sys_t {
   }
 
 
+  bool is_initialised() { return m_initialised; }
+
+
   /** Create the instance */
   void create();
 

storage/innobase/read/read0read.cc

@@ -339,7 +339,7 @@ ReadView::~ReadView()
 
 /** Constructor
 @param size		Number of views to pre-allocate */
-MVCC::MVCC(ulint size)
+void MVCC::create(ulint size)
 {
 	UT_LIST_INIT(m_free, &ReadView::m_view_list);
 	UT_LIST_INIT(m_views, &ReadView::m_view_list);
@@ -351,7 +351,7 @@ MVCC::MVCC(ulint size)
 	}
 }
 
-MVCC::~MVCC()
+void MVCC::close()
 {
 	for (ReadView* view = UT_LIST_GET_FIRST(m_free);
 	     view != NULL;

storage/innobase/row/row0sel.cc

@@ -5888,7 +5888,7 @@ row_search_check_if_query_cache_permitted(
 		    && !srv_read_only_mode
 		    && !MVCC::is_view_active(trx->read_view)) {
 
-			trx_sys.mvcc->view_open(trx->read_view, trx);
+			trx_sys.mvcc.view_open(trx->read_view, trx);
 		}
 	}
 

storage/innobase/srv/srv0srv.cc

@@ -1367,7 +1367,7 @@ srv_printf_innodb_monitor(
 
 	/* This is a dirty read, without holding trx_sys.mutex. */
 	fprintf(file, ULINTPF " read views open inside InnoDB\n",
-		trx_sys.mvcc->size());
+		trx_sys.mvcc.size());
 
 	n_reserved = fil_space_get_n_reserved_extents(0);
 	if (n_reserved > 0) {

storage/innobase/srv/srv0start.cc

@@ -2835,7 +2835,7 @@ innodb_shutdown()
 
 	ut_ad(dict_stats_event || !srv_was_started || srv_read_only_mode);
 	ut_ad(dict_sys || !srv_was_started);
-	ut_ad(trx_sys.mvcc || !srv_was_started);
+	ut_ad(trx_sys.is_initialised() || !srv_was_started);
 	ut_ad(buf_dblwr || !srv_was_started || srv_read_only_mode
 	      || srv_force_recovery >= SRV_FORCE_NO_TRX_UNDO);
 	ut_ad(lock_sys || !srv_was_started);

storage/innobase/trx/trx0purge.cc

@@ -1600,7 +1600,7 @@ trx_purge(
 	ut_a(purge_sys->n_submitted == purge_sys->n_completed);
 
 	rw_lock_x_lock(&purge_sys->latch);
-	trx_sys.mvcc->clone_oldest_view(&purge_sys->view);
+	trx_sys.mvcc.clone_oldest_view(&purge_sys->view);
 	rw_lock_x_unlock(&purge_sys->latch);
 
 #ifdef UNIV_DEBUG

storage/innobase/trx/trx0sys.cc

@@ -445,7 +445,7 @@ trx_sys_init_at_db_start()
 	trx_dummy_sess = sess_open();
 
 	trx_lists_init_at_db_start();
-	trx_sys.mvcc->clone_oldest_view(&purge_sys->view);
+	trx_sys.mvcc.clone_oldest_view(&purge_sys->view);
 }
 
 /** Create the instance */
@@ -453,13 +453,14 @@ void
 trx_sys_t::create()
 {
 	ut_ad(this == &trx_sys);
-	ut_ad(!mvcc);
+	ut_ad(!is_initialised());
+	m_initialised = true;
 	mutex_create(LATCH_ID_TRX_SYS, &mutex);
 
 	UT_LIST_INIT(serialisation_list, &trx_t::no_list);
 	UT_LIST_INIT(mysql_trx_list, &trx_t::mysql_trx_list);
 
-	mvcc = UT_NEW_NOKEY(MVCC(1024));
+	mvcc.create(1024);
 
 	rw_trx_hash.init();
 }
@@ -562,11 +563,11 @@ void
 trx_sys_t::close()
 {
 	ut_ad(srv_shutdown_state == SRV_SHUTDOWN_EXIT_THREADS);
-	if (!mvcc) {
+	if (!is_initialised()) {
 		return;
 	}
 
-	if (ulint size = mvcc->size()) {
+	if (ulint size = mvcc.size()) {
 		ib::error() << "All read views were not closed before"
 			" shutdown: " << size << " read views open";
 	}
@@ -590,13 +591,14 @@ trx_sys_t::close()
 		}
 	}
 
-	UT_DELETE(mvcc);
+	mvcc.close();
 
 	ut_a(UT_LIST_GET_LEN(mysql_trx_list) == 0);
 	ut_a(UT_LIST_GET_LEN(serialisation_list) == 0);
 
 	/* We used placement new to create this mutex. Call the destructor. */
 	mutex_free(&mutex);
+	m_initialised = false;
 }
 
 

storage/innobase/trx/trx0trx.cc

@@ -678,7 +678,7 @@ trx_disconnect_from_mysql(
 	UT_LIST_REMOVE(trx_sys.mysql_trx_list, trx);
 
 	if (trx->read_view != NULL) {
-		trx_sys.mvcc->view_close(trx->read_view, true);
+		trx_sys.mvcc.view_close(trx->read_view, true);
 	}
 
 	if (prepared) {
@@ -1558,7 +1558,7 @@ trx_erase_lists(
 
 		mutex_enter(&trx_sys.mutex);
 		if (trx->read_view != NULL) {
-			trx_sys.mvcc->view_close(trx->read_view, true);
+			trx_sys.mvcc.view_close(trx->read_view, true);
 		}
 	}
 
@@ -1615,7 +1615,7 @@ trx_commit_in_memory(
 		ut_ad(trx_state_eq(trx, TRX_STATE_ACTIVE));
 
 		if (trx->read_view != NULL) {
-			trx_sys.mvcc->view_close(trx->read_view, false);
+			trx_sys.mvcc.view_close(trx->read_view, false);
 		}
 
 		MONITOR_INC(MONITOR_TRX_NL_RO_COMMIT);
@@ -1647,7 +1647,7 @@ trx_commit_in_memory(
 		if (trx->read_only || trx->rsegs.m_redo.rseg == NULL) {
 			MONITOR_INC(MONITOR_TRX_RO_COMMIT);
 			if (trx->read_view != NULL) {
-				trx_sys.mvcc->view_close(
+				trx_sys.mvcc.view_close(
 					trx->read_view, false);
 			}
 		} else {
@@ -1911,7 +1911,7 @@ trx_assign_read_view(
 		return(NULL);
 
 	} else if (!MVCC::is_view_active(trx->read_view)) {
-		trx_sys.mvcc->view_open(trx->read_view, trx);
+		trx_sys.mvcc.view_open(trx->read_view, trx);
 	}
 
 	return(trx->read_view);