MDEV-15058: Deprecate and ignore innodb_buffer_pool_instances

Our benchmarking efforts indicate that the reasons for splitting the
buf_pool in commit c18084f
have mostly gone away, possibly as a result of
mysql/mysql-server@ce6109e
or similar work.

Only in one write-heavy benchmark where the working set size is
ten times the buffer pool size, the buf_pool->mutex would be
less contended with 4 buffer pool instances than with 1 instance,
in buf_page_io_complete(). That contention could be alleviated
further by making more use of std::atomic and by splitting
buf_pool_t::mutex further (MDEV-15053).

We will deprecate and ignore the following parameters:

	innodb_buffer_pool_instances
	innodb_page_cleaners

There will be only one buffer pool and one page cleaner task.

In a number of INFORMATION_SCHEMA views, columns that indicated
the buffer pool instance will be removed:

	information_schema.innodb_buffer_page.pool_id
	information_schema.innodb_buffer_page_lru.pool_id
	information_schema.innodb_buffer_pool_stats.pool_id
	information_schema.innodb_cmpmem.buffer_pool_instance
	information_schema.innodb_cmpmem_reset.buffer_pool_instance

extra/mariabackup/xtrabackup.cc

@@ -1905,8 +1905,6 @@ static bool innodb_init_param()
 
 	srv_buf_pool_size = (ulint) xtrabackup_use_memory;
 	srv_buf_pool_chunk_unit = (ulong)srv_buf_pool_size;
-	srv_buf_pool_instances = 1;
-	srv_n_page_cleaners = 1;
 
 	srv_n_file_io_threads = (ulint) innobase_file_io_threads;
 	srv_n_read_io_threads = (ulint) innobase_read_io_threads;

mysql-test/main/information_schema_all_engines.result

@@ -99,9 +99,9 @@ GEOMETRY_COLUMNS	F_TABLE_SCHEMA
 GLOBAL_STATUS	VARIABLE_NAME
 GLOBAL_VARIABLES	VARIABLE_NAME
 INDEX_STATISTICS	TABLE_SCHEMA
-INNODB_BUFFER_PAGE	POOL_ID
-INNODB_BUFFER_PAGE_LRU	POOL_ID
-INNODB_BUFFER_POOL_STATS	POOL_ID
+INNODB_BUFFER_PAGE	BLOCK_ID
+INNODB_BUFFER_PAGE_LRU	LRU_POSITION
+INNODB_BUFFER_POOL_STATS	POOL_SIZE
 INNODB_CMP	page_size
 INNODB_CMPMEM	page_size
 INNODB_CMPMEM_RESET	page_size
@@ -180,9 +180,9 @@ GEOMETRY_COLUMNS	F_TABLE_SCHEMA
 GLOBAL_STATUS	VARIABLE_NAME
 GLOBAL_VARIABLES	VARIABLE_NAME
 INDEX_STATISTICS	TABLE_SCHEMA
-INNODB_BUFFER_PAGE	POOL_ID
-INNODB_BUFFER_PAGE_LRU	POOL_ID
-INNODB_BUFFER_POOL_STATS	POOL_ID
+INNODB_BUFFER_PAGE	BLOCK_ID
+INNODB_BUFFER_PAGE_LRU	LRU_POSITION
+INNODB_BUFFER_POOL_STATS	POOL_SIZE
 INNODB_CMP	page_size
 INNODB_CMPMEM	page_size
 INNODB_CMPMEM_RESET	page_size

mysql-test/main/sp-group.result

@@ -22,9 +22,9 @@ ORDER BY table1.NUMBER_RECORDS
 LIMIT 0
 ;
 CALL s1;
-POOL_ID	LRU_POSITION	SPACE	PAGE_NUMBER	PAGE_TYPE	FLUSH_TYPE	FIX_COUNT	IS_HASHED	NEWEST_MODIFICATION	OLDEST_MODIFICATION	ACCESS_TIME	TABLE_NAME	INDEX_NAME	NUMBER_RECORDS	DATA_SIZE	COMPRESSED_SIZE	COMPRESSED	IO_FIX	IS_OLD	FREE_PAGE_CLOCK	pk	f0	f1	f2	f3	f4	f5	f6	f7	f8	f9
+LRU_POSITION	SPACE	PAGE_NUMBER	PAGE_TYPE	FLUSH_TYPE	FIX_COUNT	IS_HASHED	NEWEST_MODIFICATION	OLDEST_MODIFICATION	ACCESS_TIME	TABLE_NAME	INDEX_NAME	NUMBER_RECORDS	DATA_SIZE	COMPRESSED_SIZE	COMPRESSED	IO_FIX	IS_OLD	FREE_PAGE_CLOCK	pk	f0	f1	f2	f3	f4	f5	f6	f7	f8	f9
 CALL s1;
-POOL_ID	LRU_POSITION	SPACE	PAGE_NUMBER	PAGE_TYPE	FLUSH_TYPE	FIX_COUNT	IS_HASHED	NEWEST_MODIFICATION	OLDEST_MODIFICATION	ACCESS_TIME	TABLE_NAME	INDEX_NAME	NUMBER_RECORDS	DATA_SIZE	COMPRESSED_SIZE	COMPRESSED	IO_FIX	IS_OLD	FREE_PAGE_CLOCK	pk	f0	f1	f2	f3	f4	f5	f6	f7	f8	f9
+LRU_POSITION	SPACE	PAGE_NUMBER	PAGE_TYPE	FLUSH_TYPE	FIX_COUNT	IS_HASHED	NEWEST_MODIFICATION	OLDEST_MODIFICATION	ACCESS_TIME	TABLE_NAME	INDEX_NAME	NUMBER_RECORDS	DATA_SIZE	COMPRESSED_SIZE	COMPRESSED	IO_FIX	IS_OLD	FREE_PAGE_CLOCK	pk	f0	f1	f2	f3	f4	f5	f6	f7	f8	f9
 drop table t1;
 drop view view_t1;
 drop procedure s1;

mysql-test/suite/innodb/r/innodb_skip_innodb_is_tables.result

@@ -27,11 +27,11 @@ database_name	table_name	index_name	compress_ops	compress_ops_ok	compress_time	u
 Warnings:
 Warning	1012	InnoDB: SELECTing from INFORMATION_SCHEMA.innodb_cmp_per_index_reset but the InnoDB storage engine is not installed
 select * from information_schema.innodb_cmpmem;
-page_size	buffer_pool_instance	pages_used	pages_free	relocation_ops	relocation_time
+page_size	pages_used	pages_free	relocation_ops	relocation_time
 Warnings:
 Warning	1012	InnoDB: SELECTing from INFORMATION_SCHEMA.innodb_cmpmem but the InnoDB storage engine is not installed
 select * from information_schema.innodb_cmpmem_reset;
-page_size	buffer_pool_instance	pages_used	pages_free	relocation_ops	relocation_time
+page_size	pages_used	pages_free	relocation_ops	relocation_time
 Warnings:
 Warning	1012	InnoDB: SELECTing from INFORMATION_SCHEMA.innodb_cmpmem_reset but the InnoDB storage engine is not installed
 select * from information_schema.innodb_metrics;
@@ -344,11 +344,11 @@ KEY	VALUE
 Warnings:
 Warning	1012	InnoDB: SELECTing from INFORMATION_SCHEMA.innodb_ft_config but the InnoDB storage engine is not installed
 select * from information_schema.innodb_buffer_page;
-POOL_ID	BLOCK_ID	SPACE	PAGE_NUMBER	PAGE_TYPE	FLUSH_TYPE	FIX_COUNT	IS_HASHED	NEWEST_MODIFICATION	OLDEST_MODIFICATION	ACCESS_TIME	TABLE_NAME	INDEX_NAME	NUMBER_RECORDS	DATA_SIZE	COMPRESSED_SIZE	PAGE_STATE	IO_FIX	IS_OLD	FREE_PAGE_CLOCK
+BLOCK_ID	SPACE	PAGE_NUMBER	PAGE_TYPE	FLUSH_TYPE	FIX_COUNT	IS_HASHED	NEWEST_MODIFICATION	OLDEST_MODIFICATION	ACCESS_TIME	TABLE_NAME	INDEX_NAME	NUMBER_RECORDS	DATA_SIZE	COMPRESSED_SIZE	PAGE_STATE	IO_FIX	IS_OLD	FREE_PAGE_CLOCK
 Warnings:
 Warning	1012	InnoDB: SELECTing from INFORMATION_SCHEMA.innodb_buffer_page but the InnoDB storage engine is not installed
 select * from information_schema.innodb_buffer_page_lru;
-POOL_ID	LRU_POSITION	SPACE	PAGE_NUMBER	PAGE_TYPE	FLUSH_TYPE	FIX_COUNT	IS_HASHED	NEWEST_MODIFICATION	OLDEST_MODIFICATION	ACCESS_TIME	TABLE_NAME	INDEX_NAME	NUMBER_RECORDS	DATA_SIZE	COMPRESSED_SIZE	COMPRESSED	IO_FIX	IS_OLD	FREE_PAGE_CLOCK
+LRU_POSITION	SPACE	PAGE_NUMBER	PAGE_TYPE	FLUSH_TYPE	FIX_COUNT	IS_HASHED	NEWEST_MODIFICATION	OLDEST_MODIFICATION	ACCESS_TIME	TABLE_NAME	INDEX_NAME	NUMBER_RECORDS	DATA_SIZE	COMPRESSED_SIZE	COMPRESSED	IO_FIX	IS_OLD	FREE_PAGE_CLOCK
 Warnings:
 Warning	1012	InnoDB: SELECTing from INFORMATION_SCHEMA.innodb_buffer_page_lru but the InnoDB storage engine is not installed
 select * from information_schema.innodb_buffer_stats;

mysql-test/suite/innodb_i_s/innodb_buffer_page.result

@@ -1,7 +1,6 @@
 SHOW CREATE TABLE INFORMATION_SCHEMA.INNODB_BUFFER_PAGE;
 Table	Create Table
 INNODB_BUFFER_PAGE	CREATE TEMPORARY TABLE `INNODB_BUFFER_PAGE` (
-  `POOL_ID` int(11) unsigned NOT NULL DEFAULT 0,
   `BLOCK_ID` bigint(21) unsigned NOT NULL DEFAULT 0,
   `SPACE` int(11) unsigned NOT NULL DEFAULT 0,
   `PAGE_NUMBER` int(11) unsigned NOT NULL DEFAULT 0,

mysql-test/suite/innodb_i_s/innodb_buffer_page_lru.result

@@ -1,7 +1,6 @@
 SHOW CREATE TABLE INFORMATION_SCHEMA.INNODB_BUFFER_PAGE_LRU;
 Table	Create Table
 INNODB_BUFFER_PAGE_LRU	CREATE TEMPORARY TABLE `INNODB_BUFFER_PAGE_LRU` (
-  `POOL_ID` int(11) unsigned NOT NULL DEFAULT 0,
   `LRU_POSITION` bigint(21) unsigned NOT NULL DEFAULT 0,
   `SPACE` int(11) unsigned NOT NULL DEFAULT 0,
   `PAGE_NUMBER` int(11) unsigned NOT NULL DEFAULT 0,

mysql-test/suite/innodb_i_s/innodb_buffer_pool_stats.result

@@ -1,7 +1,6 @@
 SHOW CREATE TABLE INFORMATION_SCHEMA.INNODB_BUFFER_POOL_STATS;
 Table	Create Table
 INNODB_BUFFER_POOL_STATS	CREATE TEMPORARY TABLE `INNODB_BUFFER_POOL_STATS` (
-  `POOL_ID` int(11) unsigned NOT NULL DEFAULT 0,
   `POOL_SIZE` bigint(21) unsigned NOT NULL DEFAULT 0,
   `FREE_BUFFERS` bigint(21) unsigned NOT NULL DEFAULT 0,
   `DATABASE_PAGES` bigint(21) unsigned NOT NULL DEFAULT 0,

mysql-test/suite/innodb_i_s/innodb_cmpmem.result

@@ -2,7 +2,6 @@ SHOW CREATE TABLE INFORMATION_SCHEMA.INNODB_CMPMEM;
 Table	Create Table
 INNODB_CMPMEM	CREATE TEMPORARY TABLE `INNODB_CMPMEM` (
   `page_size` int(5) NOT NULL DEFAULT 0,
-  `buffer_pool_instance` int(11) NOT NULL DEFAULT 0,
   `pages_used` int(11) NOT NULL DEFAULT 0,
   `pages_free` int(11) NOT NULL DEFAULT 0,
   `relocation_ops` bigint(21) NOT NULL DEFAULT 0,

mysql-test/suite/innodb_i_s/innodb_cmpmem_reset.result

@@ -2,7 +2,6 @@ SHOW CREATE TABLE INFORMATION_SCHEMA.INNODB_CMPMEM_RESET;
 Table	Create Table
 INNODB_CMPMEM_RESET	CREATE TEMPORARY TABLE `INNODB_CMPMEM_RESET` (
   `page_size` int(5) NOT NULL DEFAULT 0,
-  `buffer_pool_instance` int(11) NOT NULL DEFAULT 0,
   `pages_used` int(11) NOT NULL DEFAULT 0,
   `pages_free` int(11) NOT NULL DEFAULT 0,
   `relocation_ops` bigint(21) NOT NULL DEFAULT 0,

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

@@ -7,32 +7,40 @@ SELECT @@innodb_page_cleaners;
 1
 1 Expected
 SET @@GLOBAL.innodb_page_cleaners=2;
+Warnings:
+Warning	138	The parameter innodb_page_cleaners is deprecated and has no effect.
 Expected to pass
 SELECT @@innodb_page_cleaners;
 @@innodb_page_cleaners
-2
+1
 2 Expected
 SET @@GLOBAL.innodb_page_cleaners=1;
+Warnings:
+Warning	138	The parameter innodb_page_cleaners is deprecated and has no effect.
 Expected to pass
 SELECT @@innodb_page_cleaners;
 @@innodb_page_cleaners
 1
 1 Expected
 SET @@GLOBAL.innodb_page_cleaners=6;
+Warnings:
+Warning	138	The parameter innodb_page_cleaners is deprecated and has no effect.
 Expected to pass
 SELECT @@innodb_page_cleaners;
 @@innodb_page_cleaners
-6
+1
 6 Expected
 SET @@GLOBAL.innodb_page_cleaners=4;
+Warnings:
+Warning	138	The parameter innodb_page_cleaners is deprecated and has no effect.
 Expected to pass
 SELECT @@innodb_page_cleaners;
 @@innodb_page_cleaners
-4
+1
 4 Expected
 SET @@GLOBAL.innodb_page_cleaners=0;
 Warnings:
-Warning	1292	Truncated incorrect innodb_page_cleaners value: '0'
+Warning	138	The parameter innodb_page_cleaners is deprecated and has no effect.
 Warning expected
 SELECT @@innodb_page_cleaners;
 @@innodb_page_cleaners

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

@@ -42,7 +42,7 @@
  VARIABLE_SCOPE	GLOBAL
 -VARIABLE_TYPE	BIGINT UNSIGNED
 +VARIABLE_TYPE	INT UNSIGNED
- VARIABLE_COMMENT	Size of a single memory chunk within each buffer pool instance for resizing buffer pool. Online buffer pool resizing happens at this granularity. 0 means disable resizing buffer pool.
+ VARIABLE_COMMENT	Size of a single memory chunk for resizing buffer pool. Online buffer pool resizing happens at this granularity. 0 means disable resizing buffer pool.
  NUMERIC_MIN_VALUE	1048576
 -NUMERIC_MAX_VALUE	9223372036854775807
 +NUMERIC_MAX_VALUE	2147483647
@@ -64,7 +64,7 @@
  VARIABLE_SCOPE	GLOBAL
 -VARIABLE_TYPE	BIGINT UNSIGNED
 +VARIABLE_TYPE	INT UNSIGNED
- VARIABLE_COMMENT	Number of buffer pool instances, set to higher value on high-end machines to increase scalability
+ VARIABLE_COMMENT	Deprecated parameter with no effect.
  NUMERIC_MIN_VALUE	0
  NUMERIC_MAX_VALUE	64
 @@ -289,7 +289,7 @@
@@ -377,8 +377,8 @@
  VARIABLE_SCOPE	GLOBAL
 -VARIABLE_TYPE	BIGINT UNSIGNED
 +VARIABLE_TYPE	INT UNSIGNED
- VARIABLE_COMMENT	Page cleaner threads can be from 1 to 64. Default is 4.
- NUMERIC_MIN_VALUE	1
+ VARIABLE_COMMENT	Deprecated parameter with no effect.
+ NUMERIC_MIN_VALUE	0
  NUMERIC_MAX_VALUE	64
 @@ -1513,7 +1513,7 @@
  SESSION_VALUE	NULL

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

@@ -158,7 +158,7 @@ SESSION_VALUE	NULL
 DEFAULT_VALUE	134217728
 VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	BIGINT UNSIGNED
-VARIABLE_COMMENT	Size of a single memory chunk within each buffer pool instance for resizing buffer pool. Online buffer pool resizing happens at this granularity. 0 means disable resizing buffer pool.
+VARIABLE_COMMENT	Size of a single memory chunk for resizing buffer pool. Online buffer pool resizing happens at this granularity. 0 means disable resizing buffer pool.
 NUMERIC_MIN_VALUE	1048576
 NUMERIC_MAX_VALUE	9223372036854775807
 NUMERIC_BLOCK_SIZE	1048576
@@ -230,7 +230,7 @@ SESSION_VALUE	NULL
 DEFAULT_VALUE	0
 VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	BIGINT UNSIGNED
-VARIABLE_COMMENT	Number of buffer pool instances, set to higher value on high-end machines to increase scalability
+VARIABLE_COMMENT	Deprecated parameter with no effect.
 NUMERIC_MIN_VALUE	0
 NUMERIC_MAX_VALUE	64
 NUMERIC_BLOCK_SIZE	0
@@ -1487,11 +1487,11 @@ READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	NONE
 VARIABLE_NAME	INNODB_PAGE_CLEANERS
 SESSION_VALUE	NULL
-DEFAULT_VALUE	4
+DEFAULT_VALUE	0
 VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	BIGINT UNSIGNED
-VARIABLE_COMMENT	Page cleaner threads can be from 1 to 64. Default is 4.
-NUMERIC_MIN_VALUE	1
+VARIABLE_COMMENT	Deprecated parameter with no effect.
+NUMERIC_MIN_VALUE	0
 NUMERIC_MAX_VALUE	64
 NUMERIC_BLOCK_SIZE	0
 ENUM_VALUE_LIST	NULL

mysql-test/suite/sys_vars/t/innodb_buffer_pool_dump_pct_function.opt

@@ -2,5 +2,4 @@
 --loose-innodb_buffer_pool_load_at_startup=0
 --loose-innodb_buffer_pool_dump_at_shutdown=0
 --loose-innodb-buffer-pool-size=8M
---loose-innodb-buffer-pool-instances=1
 --loose-innodb-page-size=16k

storage/innobase/btr/btr0btr.cc

@@ -1391,7 +1391,6 @@ btr_page_reorganize_low(
 	mtr_t*		mtr)	/*!< in/out: mini-transaction */
 {
 	buf_block_t*	block		= page_cur_get_block(cursor);
-	buf_pool_t*	buf_pool	= buf_pool_from_bpage(&block->page);
 	page_t*		page		= buf_block_get_frame(block);
 	page_zip_des_t*	page_zip	= buf_block_get_page_zip(block);
 	buf_block_t*	temp_block;
@@ -1420,7 +1419,7 @@ btr_page_reorganize_low(
 	/* Turn logging off */
 	mtr_log_t	log_mode = mtr_set_log_mode(mtr, MTR_LOG_NONE);
 
-	temp_block = buf_block_alloc(buf_pool);
+	temp_block = buf_block_alloc();
 
 	MONITOR_INC(MONITOR_INDEX_REORG_ATTEMPTS);