MDEV-24536 innodb_idle_flush_pct has no effect

The parameter innodb_idle_flush_pct that was introduced in
MariaDB Server 10.1.2 by MDEV-6932 has no effect ever since
the InnoDB changes from MySQL 5.7.9 were applied in
commit 2e814d47.

Let us declare the parameter as MARIADB_REMOVED_OPTION.
For earlier versions, commit ea9cd97f
declared the parameter deprecated.

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

-SET @start_global_value = @@global.innodb_idle_flush_pct;
-SELECT @start_global_value;
-@start_global_value
-100
-Valid values are between 0 and 100
-select @@global.innodb_idle_flush_pct between 0 and 100;
-@@global.innodb_idle_flush_pct between 0 and 100
-1
-select @@global.innodb_idle_flush_pct;
-@@global.innodb_idle_flush_pct
-100
-select @@session.innodb_idle_flush_pct;
-ERROR HY000: Variable 'innodb_idle_flush_pct' is a GLOBAL variable
-show global variables like 'innodb_idle_flush_pct';
-Variable_name	Value
-innodb_idle_flush_pct	100
-show session variables like 'innodb_idle_flush_pct';
-Variable_name	Value
-innodb_idle_flush_pct	100
-select * from information_schema.global_variables where variable_name='innodb_idle_flush_pct';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_IDLE_FLUSH_PCT	100
-select * from information_schema.session_variables where variable_name='innodb_idle_flush_pct';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_IDLE_FLUSH_PCT	100
-set global innodb_idle_flush_pct=10;
-select @@global.innodb_idle_flush_pct;
-@@global.innodb_idle_flush_pct
-10
-select * from information_schema.global_variables where variable_name='innodb_idle_flush_pct';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_IDLE_FLUSH_PCT	10
-select * from information_schema.session_variables where variable_name='innodb_idle_flush_pct';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_IDLE_FLUSH_PCT	10
-set session innodb_idle_flush_pct=1;
-ERROR HY000: Variable 'innodb_idle_flush_pct' is a GLOBAL variable and should be set with SET GLOBAL
-set global innodb_idle_flush_pct=1.1;
-ERROR 42000: Incorrect argument type to variable 'innodb_idle_flush_pct'
-set global innodb_idle_flush_pct=1e1;
-ERROR 42000: Incorrect argument type to variable 'innodb_idle_flush_pct'
-set global innodb_idle_flush_pct="bar";
-ERROR 42000: Incorrect argument type to variable 'innodb_idle_flush_pct'
-set global innodb_idle_flush_pct=-7;
-Warnings:
-Warning	1292	Truncated incorrect innodb_idle_flush_pct value: '-7'
-select @@global.innodb_idle_flush_pct;
-@@global.innodb_idle_flush_pct
-0
-select * from information_schema.global_variables where variable_name='innodb_idle_flush_pct';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_IDLE_FLUSH_PCT	0
-set global innodb_idle_flush_pct=106;
-Warnings:
-Warning	1292	Truncated incorrect innodb_idle_flush_pct value: '106'
-select @@global.innodb_idle_flush_pct;
-@@global.innodb_idle_flush_pct
-100
-select * from information_schema.global_variables where variable_name='innodb_idle_flush_pct';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_IDLE_FLUSH_PCT	100
-set global innodb_idle_flush_pct=0;
-select @@global.innodb_idle_flush_pct;
-@@global.innodb_idle_flush_pct
-0
-set global innodb_idle_flush_pct=100;
-select @@global.innodb_idle_flush_pct;
-@@global.innodb_idle_flush_pct
-100
-set global innodb_idle_flush_pct=DEFAULT;
-select @@global.innodb_idle_flush_pct;
-@@global.innodb_idle_flush_pct
-100
-SET @@global.innodb_idle_flush_pct = @start_global_value;
-SELECT @@global.innodb_idle_flush_pct;
-@@global.innodb_idle_flush_pct
-100

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

@@ -188,15 +188,6 @@
  VARIABLE_COMMENT	Total memory allocated for InnoDB Fulltext Search cache
  NUMERIC_MIN_VALUE	32000000
  NUMERIC_MAX_VALUE	1600000000
-@@ -1057,7 +1057,7 @@
- SESSION_VALUE	NULL
- DEFAULT_VALUE	100
- VARIABLE_SCOPE	GLOBAL
--VARIABLE_TYPE	BIGINT UNSIGNED
-+VARIABLE_TYPE	INT UNSIGNED
- VARIABLE_COMMENT	Up to what percentage of dirty pages should be flushed when innodb finds it has spare resources to do so.
- NUMERIC_MIN_VALUE	0
- NUMERIC_MAX_VALUE	100
 @@ -1093,22 +1093,22 @@
  SESSION_VALUE	NULL
  DEFAULT_VALUE	200

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

@@ -1053,18 +1053,6 @@ NUMERIC_BLOCK_SIZE	NULL
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	OPTIONAL
-VARIABLE_NAME	INNODB_IDLE_FLUSH_PCT
-SESSION_VALUE	NULL
-DEFAULT_VALUE	100
-VARIABLE_SCOPE	GLOBAL
-VARIABLE_TYPE	BIGINT UNSIGNED
-VARIABLE_COMMENT	Up to what percentage of dirty pages should be flushed when innodb finds it has spare resources to do so.
-NUMERIC_MIN_VALUE	0
-NUMERIC_MAX_VALUE	100
-NUMERIC_BLOCK_SIZE	0
-ENUM_VALUE_LIST	NULL
-READ_ONLY	NO
-COMMAND_LINE_ARGUMENT	REQUIRED
 VARIABLE_NAME	INNODB_IMMEDIATE_SCRUB_DATA_UNCOMPRESSED
 SESSION_VALUE	NULL
 DEFAULT_VALUE	OFF

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

-
-#
-# 2013-04-01 - Added
-#
-
---source include/have_innodb.inc
-
-SET @start_global_value = @@global.innodb_idle_flush_pct;
-SELECT @start_global_value;
-
-#
-# exists as global only
-#
---echo Valid values are between 0 and 100
-select @@global.innodb_idle_flush_pct between 0 and 100;
-select @@global.innodb_idle_flush_pct;
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-select @@session.innodb_idle_flush_pct;
-show global variables like 'innodb_idle_flush_pct';
-show session variables like 'innodb_idle_flush_pct';
-select * from information_schema.global_variables where variable_name='innodb_idle_flush_pct';
-select * from information_schema.session_variables where variable_name='innodb_idle_flush_pct';
-
-#
-# show that it's writable
-#
-set global innodb_idle_flush_pct=10;
-select @@global.innodb_idle_flush_pct;
-select * from information_schema.global_variables where variable_name='innodb_idle_flush_pct';
-select * from information_schema.session_variables where variable_name='innodb_idle_flush_pct';
---error ER_GLOBAL_VARIABLE
-set session innodb_idle_flush_pct=1;
-
-#
-# incorrect types
-#
---error ER_WRONG_TYPE_FOR_VAR
-set global innodb_idle_flush_pct=1.1;
---error ER_WRONG_TYPE_FOR_VAR
-set global innodb_idle_flush_pct=1e1;
---error ER_WRONG_TYPE_FOR_VAR
-set global innodb_idle_flush_pct="bar";
-
-set global innodb_idle_flush_pct=-7;
-select @@global.innodb_idle_flush_pct;
-select * from information_schema.global_variables where variable_name='innodb_idle_flush_pct';
-set global innodb_idle_flush_pct=106;
-select @@global.innodb_idle_flush_pct;
-select * from information_schema.global_variables where variable_name='innodb_idle_flush_pct';
-
-#
-# min/max/DEFAULT values
-#
-set global innodb_idle_flush_pct=0;
-select @@global.innodb_idle_flush_pct;
-set global innodb_idle_flush_pct=100;
-select @@global.innodb_idle_flush_pct;
-set global innodb_idle_flush_pct=DEFAULT;
-select @@global.innodb_idle_flush_pct;
-
-
-SET @@global.innodb_idle_flush_pct = @start_global_value;
-SELECT @@global.innodb_idle_flush_pct;

sql/mysqld.cc

 /* Copyright (c) 2000, 2015, Oracle and/or its affiliates.
-   Copyright (c) 2008, 2020, MariaDB
+   Copyright (c) 2008, 2021, MariaDB
 
    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
@@ -4979,6 +4979,7 @@ static int init_server_components()
 #if defined(__linux__)
       MARIADB_REMOVED_OPTION("super-large-pages"),
 #endif
+      MARIADB_REMOVED_OPTION("innodb-idle-flush-pct"),
       MARIADB_REMOVED_OPTION("innodb-locks-unsafe-for-binlog"),
       MARIADB_REMOVED_OPTION("innodb-rollback-segments"),
       MARIADB_REMOVED_OPTION("innodb-stats-sample-pages"),

sql/upgrade_conf_file.cc

@@ -76,6 +76,7 @@ static const char *removed_variables[] =
 "innodb_ibuf_accel_rate",
 "innodb_ibuf_active_contract",
 "innodb_ibuf_max_size",
+"innodb_idle_flush_pct",
 "innodb_import_table_from_xtrabackup",
 "innodb_instrument_semaphores",
 "innodb_kill_idle_transaction",

storage/innobase/handler/ha_innodb.cc

@@ -18892,13 +18892,6 @@ static MYSQL_SYSVAR_ULONG(io_capacity_max, srv_max_io_capacity,
   SRV_MAX_IO_CAPACITY_DUMMY_DEFAULT, 100,
   SRV_MAX_IO_CAPACITY_LIMIT, 0);
 
-static MYSQL_SYSVAR_ULONG(idle_flush_pct,
-  srv_idle_flush_pct,
-  PLUGIN_VAR_RQCMDARG,
-  "Up to what percentage of dirty pages should be flushed when innodb "
-  "finds it has spare resources to do so.",
-  NULL, NULL, 100, 0, 100, 0);
-
 #ifdef UNIV_DEBUG
 static MYSQL_SYSVAR_BOOL(background_drop_list_empty,
   innodb_background_drop_list_empty,
@@ -20057,7 +20050,6 @@ static struct st_mysql_sys_var* innobase_system_variables[]= {
   MYSQL_SYSVAR(io_capacity),
   MYSQL_SYSVAR(io_capacity_max),
   MYSQL_SYSVAR(page_cleaners),
-  MYSQL_SYSVAR(idle_flush_pct),
   MYSQL_SYSVAR(monitor_enable),
   MYSQL_SYSVAR(monitor_disable),
   MYSQL_SYSVAR(monitor_reset),

storage/innobase/include/srv0srv.h

@@ -348,8 +348,6 @@ extern double	srv_defragment_fill_factor;
 extern uint	srv_defragment_frequency;
 extern ulonglong	srv_defragment_interval;
 
-extern ulong	srv_idle_flush_pct;
-
 extern uint	srv_change_buffer_max_size;
 
 /* Number of IO operations per second the server can do */

storage/innobase/srv/srv0srv.cc

@@ -224,9 +224,6 @@ ulong srv_buf_pool_load_pages_abort = LONG_MAX;
 /** Lock table size in bytes */
 ulint	srv_lock_table_size	= ULINT_MAX;
 
-/** innodb_idle_flush_pct */
-ulong	srv_idle_flush_pct;
-
 /** innodb_read_io_threads */
 uint	srv_n_read_io_threads;
 /** innodb_write_io_threads */