MDEV-13690: Remove unnecessary innodb_use_mtflush, innodb_mtflush_threads...

MDEV-13690: Remove unnecessary innodb_use_mtflush, innodb_mtflush_threads parameters and related code

Users can use innodb-page-cleaners instead.

mysql-test/suite/sys_vars/r/innodb_mtflush_threads_basic.result

-select @@global.innodb_mtflush_threads;
-@@global.innodb_mtflush_threads
-8
-select @@session.innodb_mtflush_threads;
-ERROR HY000: Variable 'innodb_mtflush_threads' is a GLOBAL variable
-show global variables like 'innodb_mtflush_threads';
-Variable_name	Value
-innodb_mtflush_threads	8
-show session variables like 'innodb_mtflush_threads';
-Variable_name	Value
-innodb_mtflush_threads	8
-select * from information_schema.global_variables where variable_name='innodb_mtflush_threads';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_MTFLUSH_THREADS	8
-select * from information_schema.session_variables where variable_name='innodb_mtflush_threads';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_MTFLUSH_THREADS	8
-set global innodb_mtflush_threads=1;
-ERROR HY000: Variable 'innodb_mtflush_threads' is a read only variable
-set session innodb_mtflush_threads=1;
-ERROR HY000: Variable 'innodb_mtflush_threads' is a read only variable

mysql-test/suite/sys_vars/r/innodb_use_mtflush_basic.result

-select @@global.innodb_use_mtflush;
-@@global.innodb_use_mtflush
-0
-select @@session.innodb_use_mtflush;
-ERROR HY000: Variable 'innodb_use_mtflush' is a GLOBAL variable
-show global variables like 'innodb_use_mtflush';
-Variable_name	Value
-innodb_use_mtflush	OFF
-show session variables like 'innodb_use_mtflush';
-Variable_name	Value
-innodb_use_mtflush	OFF
-select * from information_schema.global_variables where variable_name='innodb_use_mtflush';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_USE_MTFLUSH	OFF
-select * from information_schema.session_variables where variable_name='innodb_use_mtflush';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_USE_MTFLUSH	OFF
-set global innodb_use_mtflush=1;
-ERROR HY000: Variable 'innodb_use_mtflush' is a read only variable
-set session innodb_use_mtflush=1;
-ERROR HY000: Variable 'innodb_use_mtflush' is a read only variable

mysql-test/suite/sys_vars/r/sysvars_innodb,32bit.rdiff

@@ -364,15 +364,6 @@
  VARIABLE_COMMENT	Maximum delay of user threads in micro-seconds
  NUMERIC_MIN_VALUE	0
  NUMERIC_MAX_VALUE	10000000
-@@ -1636,7 +1636,7 @@
- GLOBAL_VALUE_ORIGIN	COMPILE-TIME
- DEFAULT_VALUE	8
- VARIABLE_SCOPE	GLOBAL
--VARIABLE_TYPE	BIGINT
-+VARIABLE_TYPE	INT
- VARIABLE_COMMENT	DEPRECATED. Number of multi-threaded flush threads
- NUMERIC_MIN_VALUE	1
- NUMERIC_MAX_VALUE	64
 @@ -1692,10 +1692,10 @@
  GLOBAL_VALUE_ORIGIN	COMPILE-TIME
  DEFAULT_VALUE	0

mysql-test/suite/sys_vars/r/sysvars_innodb.result

@@ -1630,20 +1630,6 @@ NUMERIC_BLOCK_SIZE	NULL
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	REQUIRED
-VARIABLE_NAME	INNODB_MTFLUSH_THREADS
-SESSION_VALUE	NULL
-GLOBAL_VALUE	8
-GLOBAL_VALUE_ORIGIN	COMPILE-TIME
-DEFAULT_VALUE	8
-VARIABLE_SCOPE	GLOBAL
-VARIABLE_TYPE	BIGINT
-VARIABLE_COMMENT	DEPRECATED. Number of multi-threaded flush threads
-NUMERIC_MIN_VALUE	1
-NUMERIC_MAX_VALUE	64
-NUMERIC_BLOCK_SIZE	0
-ENUM_VALUE_LIST	NULL
-READ_ONLY	YES
-COMMAND_LINE_ARGUMENT	REQUIRED
 VARIABLE_NAME	INNODB_OLD_BLOCKS_PCT
 SESSION_VALUE	NULL
 GLOBAL_VALUE	37
@@ -2442,20 +2428,6 @@ NUMERIC_BLOCK_SIZE	NULL
 ENUM_VALUE_LIST	OFF,ON
 READ_ONLY	YES
 COMMAND_LINE_ARGUMENT	NONE
-VARIABLE_NAME	INNODB_USE_MTFLUSH
-SESSION_VALUE	NULL
-GLOBAL_VALUE	OFF
-GLOBAL_VALUE_ORIGIN	COMPILE-TIME
-DEFAULT_VALUE	OFF
-VARIABLE_SCOPE	GLOBAL
-VARIABLE_TYPE	BOOLEAN
-VARIABLE_COMMENT	DEPRECATED. Use multi-threaded flush. Default FALSE.
-NUMERIC_MIN_VALUE	NULL
-NUMERIC_MAX_VALUE	NULL
-NUMERIC_BLOCK_SIZE	NULL
-ENUM_VALUE_LIST	OFF,ON
-READ_ONLY	YES
-COMMAND_LINE_ARGUMENT	NONE
 VARIABLE_NAME	INNODB_VERSION
 SESSION_VALUE	NULL
 GLOBAL_VALUE	5.7.19

mysql-test/suite/sys_vars/t/innodb_mtflush_threads_basic.test

---source include/have_innodb.inc
-# bool readonly
-
-#
-# show values;
-#
-select @@global.innodb_mtflush_threads;
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-select @@session.innodb_mtflush_threads;
-show global variables like 'innodb_mtflush_threads';
-show session variables like 'innodb_mtflush_threads';
-select * from information_schema.global_variables where variable_name='innodb_mtflush_threads';
-select * from information_schema.session_variables where variable_name='innodb_mtflush_threads';
-
-#
-# show that it's read-only
-#
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-set global innodb_mtflush_threads=1;
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-set session innodb_mtflush_threads=1;

mysql-test/suite/sys_vars/t/innodb_use_mtflush_basic.test

---source include/have_innodb.inc
-# bool readonly
-
-#
-# show values;
-#
-select @@global.innodb_use_mtflush;
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-select @@session.innodb_use_mtflush;
-show global variables like 'innodb_use_mtflush';
-show session variables like 'innodb_use_mtflush';
-select * from information_schema.global_variables where variable_name='innodb_use_mtflush';
-select * from information_schema.session_variables where variable_name='innodb_use_mtflush';
-
-#
-# show that it's read-only
-#
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-set global innodb_use_mtflush=1;
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-set session innodb_use_mtflush=1;
-

storage/innobase/CMakeLists.txt

@@ -36,7 +36,6 @@ SET(INNOBASE_SOURCES
 	buf/buf0flu.cc
 	buf/buf0lru.cc
 	buf/buf0rea.cc
-	buf/buf0mtflu.cc
 	data/data0data.cc
 	data/data0type.cc
 	dict/dict0boot.cc

storage/innobase/buf/buf0flu.cc

@@ -31,7 +31,6 @@ Created 11/11/1995 Heikki Tuuri
 
 #include "buf0flu.h"
 #include "buf0buf.h"
-#include "buf0mtflu.h"
 #include "buf0checksum.h"
 #include "srv0start.h"
 #include "srv0srv.h"
@@ -2142,10 +2141,6 @@ buf_flush_lists(
 	ulint		n_flushed = 0;
 	bool		success = true;
 
-	if (buf_mtflu_init_done()) {
-		return(buf_mtflu_flush_list(min_n, lsn_limit, n_processed));
-	}
-
 	if (n_processed) {
 		*n_processed = 0;
 	}
@@ -2304,11 +2299,6 @@ buf_flush_LRU_list(
 
 	memset(&n, 0, sizeof(flush_counters_t));
 
-	if(buf_mtflu_init_done())
-	{
-		return(buf_mtflu_flush_LRU_tail());
-	}
-
 	ut_ad(buf_pool);
 	/* srv_LRU_scan_depth can be arbitrarily large value.
 	We cap it with current LRU size. */

storage/innobase/handler/ha_innodb.cc

@@ -3645,16 +3645,6 @@ static uint innobase_partition_flags()
 	return (0);
 }
 
-static const char*	deprecated_use_mtflush
-	= "Using innodb_use_mtflush is deprecated"
-	" and the parameter will be removed in MariaDB 10.3."
-	" Use innodb-page-cleaners instead. ";
-
-static const char*	deprecated_mtflush_threads
-	= "Using innodb_mtflush_threads is deprecated"
-	" and the parameter will be removed in MariaDB 10.3."
-	" Use innodb-page-cleaners instead. ";
-
 /** Update log_checksum_algorithm_ptr with a pointer to the function
 corresponding to whether checksums are enabled.
 @param[in,out]	thd	client session, or NULL if at startup
@@ -3992,14 +3982,6 @@ innobase_init(
 		DBUG_RETURN(innobase_init_abort());
 	}
 
-	if (srv_use_mtflush) {
-		ib::warn() << deprecated_use_mtflush;
-	}
-
-	if (srv_use_mtflush && srv_mtflush_threads != MTFLUSH_DEFAULT_WORKER) {
-		ib::warn() << deprecated_mtflush_threads;
-	}
-
 	if (innobase_change_buffering) {
 		ulint	use;
 
@@ -21012,20 +20994,6 @@ static MYSQL_SYSVAR_ENUM(compression_algorithm, innodb_compression_algorithm,
   PAGE_ZLIB_ALGORITHM,
   &page_compression_algorithms_typelib);
 
-static MYSQL_SYSVAR_LONG(mtflush_threads, srv_mtflush_threads,
-  PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
-  "DEPRECATED. Number of multi-threaded flush threads",
-  NULL, NULL,
-  MTFLUSH_DEFAULT_WORKER, /* Default setting */
-  1,                      /* Minimum setting */
-  MTFLUSH_MAX_WORKER,     /* Max setting */
-  0);
-
-static MYSQL_SYSVAR_BOOL(use_mtflush, srv_use_mtflush,
-  PLUGIN_VAR_NOCMDARG | PLUGIN_VAR_READONLY,
-  "DEPRECATED. Use multi-threaded flush. Default FALSE.",
-  NULL, NULL, FALSE);
-
 static MYSQL_SYSVAR_ULONG(fatal_semaphore_wait_threshold, srv_fatal_semaphore_wait_threshold,
   PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
   "Maximum number of seconds that semaphore times out in InnoDB.",
@@ -21324,8 +21292,6 @@ static struct st_mysql_sys_var* innobase_system_variables[]= {
   /* Table page compression feature */
   MYSQL_SYSVAR(compression_default),
   MYSQL_SYSVAR(compression_algorithm),
-  MYSQL_SYSVAR(mtflush_threads),
-  MYSQL_SYSVAR(use_mtflush),
   /* Encryption feature */
   MYSQL_SYSVAR(encrypt_tables),
   MYSQL_SYSVAR(encryption_threads),

storage/innobase/include/buf0mtflu.h

-/*****************************************************************************
-
-Copyright (C) 2014 SkySQL Ab. All Rights Reserved.
-Copyright (C) 2014 Fusion-io. All Rights Reserved.
-
-This program is free software; you can redistribute it and/or modify it under
-the terms of the GNU General Public License as published by the Free Software
-Foundation; version 2 of the License.
-
-This program is distributed in the hope that it will be useful, but WITHOUT
-ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
-FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License along with
-this program; if not, write to the Free Software Foundation, Inc.,
-51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
-
-*****************************************************************************/
-
-/******************************************************************//**
-@file include/buf0mtflu.h
-Multi-threadef flush method interface function prototypes
-
-Created 06/02/2014 Jan Lindström jan.lindstrom@skysql.com
-		   Dhananjoy Das DDas@fusionio.com
-***********************************************************************/
-
-#ifndef buf0mtflu_h
-#define buf0mtflu_h
-
-/******************************************************************//**
-Add exit work item to work queue to signal multi-threded flush
-threads that they should exit.
-*/
-void
-buf_mtflu_io_thread_exit(void);
-/*===========================*/
-
-/******************************************************************//**
-Initialize multi-threaded flush thread syncronization data.
-@return Initialized multi-threaded flush thread syncroniztion data. */
-void*
-buf_mtflu_handler_init(
-/*===================*/
-	ulint n_threads,	/*!< in: Number of threads to create */
-	ulint wrk_cnt);		/*!< in: Number of work items */
-
-/******************************************************************//**
-Return true if multi-threaded flush is initialized
-@return true if initialized, false if not */
-bool
-buf_mtflu_init_done(void);
-/*======================*/
-
-/*********************************************************************//**
-Clears up tail of the LRU lists:
-* Put replaceable pages at the tail of LRU to the free list
-* Flush dirty pages at the tail of LRU to the disk
-The depth to which we scan each buffer pool is controlled by dynamic
-config parameter innodb_LRU_scan_depth.
-@return total pages flushed */
-UNIV_INTERN
-ulint
-buf_mtflu_flush_LRU_tail(void);
-/*===========================*/
-
-/*******************************************************************//**
-Multi-threaded version of buf_flush_list
-*/
-bool
-buf_mtflu_flush_list(
-/*=================*/
-	ulint		min_n,		/*!< in: wished minimum mumber of blocks
-					flushed (it is not guaranteed that the
-					actual number is that big, though) */
-	lsn_t		lsn_limit,	/*!< in the case BUF_FLUSH_LIST all
-					blocks whose oldest_modification is
-					smaller than this should be flushed
-					(if their number does not exceed
-					min_n), otherwise ignored */
-	ulint*		n_processed);	/*!< out: the number of pages
-					which were processed is passed
-					back to caller. Ignored if NULL */
-
-/*********************************************************************//**
-Set correct thread identifiers to io thread array based on
-information we have. */
-void
-buf_mtflu_set_thread_ids(
-/*=====================*/
-	ulint n_threads,		/*!<in: Number of threads to fill */
-	void* ctx,		        /*!<in: thread context */
-	os_thread_id_t* thread_ids);	/*!<in: thread id array */
-
-#endif

storage/innobase/include/srv0srv.h

@@ -275,16 +275,6 @@ extern my_bool srv_use_atomic_writes;
 /* Compression algorithm*/
 extern ulong innodb_compression_algorithm;
 
-/* Number of flush threads */
-#define MTFLUSH_MAX_WORKER		64
-#define MTFLUSH_DEFAULT_WORKER		8
-
-/* Number of threads used for multi-threaded flush */
-extern long    srv_mtflush_threads;
-
-/* If this flag is TRUE, then we will use multi threaded flush. */
-extern my_bool	srv_use_mtflush;
-
 /** TRUE if the server was successfully started */
 extern bool	srv_was_started;
 

storage/innobase/include/sync0types.h

@@ -379,8 +379,6 @@ enum latch_id_t {
 	LATCH_ID_SCRUB_STAT_MUTEX,
 	LATCH_ID_DEFRAGMENT_MUTEX,
 	LATCH_ID_BTR_DEFRAGMENT_MUTEX,
-	LATCH_ID_MTFLUSH_THREAD_MUTEX,
-	LATCH_ID_MTFLUSH_MUTEX,
 	LATCH_ID_FIL_CRYPT_MUTEX,
 	LATCH_ID_FIL_CRYPT_STAT_MUTEX,
 	LATCH_ID_FIL_CRYPT_DATA_MUTEX,

storage/innobase/srv/srv0srv.cc

@@ -172,10 +172,6 @@ my_bool	srv_numa_interleave;
 my_bool	srv_use_atomic_writes;
 /** innodb_compression_algorithm; used with page compression */
 ulong	innodb_compression_algorithm;
-/** innodb_mtflush_threads; number of threads used for multi-threaded flush */
-long srv_mtflush_threads;
-/** innodb_use_mtflush; whether to use multi threaded flush. */
-my_bool	srv_use_mtflush;
 
 #ifdef UNIV_DEBUG
 /** Used by SET GLOBAL innodb_master_thread_disabled_debug = X. */

storage/innobase/srv/srv0start.cc

@@ -83,7 +83,6 @@ Created 2/16/1996 Heikki Tuuri
 #include "os0proc.h"
 #include "buf0flu.h"
 #include "buf0rea.h"
-#include "buf0mtflu.h"
 #include "dict0boot.h"
 #include "dict0load.h"
 #include "dict0stats_bg.h"
@@ -191,9 +190,7 @@ static ulint		n[SRV_MAX_N_IO_THREADS + 6];
 /** io_handler_thread identifiers, 32 is the maximum number of purge threads  */
 /** 6 is the ? */
 #define	START_OLD_THREAD_CNT	(SRV_MAX_N_IO_THREADS + 6 + 32)
-static os_thread_id_t	thread_ids[SRV_MAX_N_IO_THREADS + 6 + 32 + MTFLUSH_MAX_WORKER];
-/* Thread contex data for multi-threaded flush */
-void *mtflush_ctx=NULL;
+static os_thread_id_t	thread_ids[SRV_MAX_N_IO_THREADS + 6 + 32];
 
 /** Thead handles */
 static os_thread_t	thread_handles[SRV_MAX_N_IO_THREADS + 6 + 32];
@@ -1307,10 +1304,6 @@ srv_shutdown_all_bg_threads()
 			}
 
 			os_event_set(buf_flush_event);
-
-			if (srv_use_mtflush) {
-				buf_mtflu_io_thread_exit();
-			}
 		}
 
 		if (!os_thread_count) {
@@ -2633,19 +2626,6 @@ innobase_start_or_create_for_mysql()
 	if (!srv_read_only_mode) {
 		/* wake main loop of page cleaner up */
 		os_event_set(buf_flush_event);
-
-		if (srv_use_mtflush) {
-			/* Start multi-threaded flush threads */
-			mtflush_ctx = buf_mtflu_handler_init(
-				srv_mtflush_threads,
-				srv_buf_pool_instances);
-
-			/* Set up the thread ids */
-			buf_mtflu_set_thread_ids(
-				srv_mtflush_threads,
-				mtflush_ctx,
-				(thread_ids + 6 + 32));
-		}
 	}
 
 	if (srv_print_verbose_log) {

storage/innobase/sync/sync0debug.cc

@@ -1552,10 +1552,6 @@ sync_latch_meta_init()
 			PFS_NOT_INSTRUMENTED);
 	LATCH_ADD_MUTEX(BTR_DEFRAGMENT_MUTEX, SYNC_NO_ORDER_CHECK,
 			PFS_NOT_INSTRUMENTED);
-	LATCH_ADD_MUTEX(MTFLUSH_THREAD_MUTEX,  SYNC_NO_ORDER_CHECK,
-			PFS_NOT_INSTRUMENTED);
-	LATCH_ADD_MUTEX(MTFLUSH_MUTEX, SYNC_NO_ORDER_CHECK,
-			PFS_NOT_INSTRUMENTED);
 	LATCH_ADD_MUTEX(FIL_CRYPT_MUTEX, SYNC_NO_ORDER_CHECK,
 			PFS_NOT_INSTRUMENTED);
 	LATCH_ADD_MUTEX(FIL_CRYPT_STAT_MUTEX, SYNC_NO_ORDER_CHECK,