MDEV-6930: Make innodb_max_dirty_pages_pct my.cnf variable a double

Merged Facebook commit ecff018632c6db49bad73d9233c3cdc9f41430e9
authored by Steaphan Greene from https://github.com/facebook/mysql-5.6

This change is to fix: http://bugs.mysql.com/62534

This makes innodb_max_dirty_pages_pct a double with min,default,max values
0.001, 75, 99.999.

This also makes innodb_max_dirty_pages_pct_lwm and adaptive_flushing_lwm
doubles, as these sysvars are inter-dependent.

Added more to the BUFFER POOL AND MEMORY section of SHOW INNODB STATUS:
Percent pages dirty: X.X
This is all n_dirty_pages / used_pages
Percent all pages dirty: X.X
This is all n_dirty_pages / all-pages
Max dirty pages percent: X.X
This is innodb_max_dirty_pages_pct

Also changed all of buf from 2 to 3 digits of precision (%.2f -> %.3f).

16 files changed, 125 insertions, 107 deletions

diff --git a/mysql-test/suite/sys_vars/r/innodb_adaptive_flushing_lwm_basic.result b/mysql-test/suite/sys_vars/r/innodb_adaptive_flushing_lwm_basic.result
index 1797845def2..bfd59cfd9cc 100644
--- a/mysql-test/suite/sys_vars/r/innodb_adaptive_flushing_lwm_basic.result
+++ b/mysql-test/suite/sys_vars/r/innodb_adaptive_flushing_lwm_basic.result
@@ -7,55 +7,55 @@ SET @@global.innodb_adaptive_flushing_lwm = 1;
 SET @@global.innodb_adaptive_flushing_lwm = DEFAULT;
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-10
+10.000000
 '#---------------------FN_DYNVARS_046_02-------------------------#'
 SET innodb_adaptive_flushing_lwm = 1;
 ERROR HY000: Variable 'innodb_adaptive_flushing_lwm' is a GLOBAL variable and should be set with SET GLOBAL
 SELECT @@innodb_adaptive_flushing_lwm;
 @@innodb_adaptive_flushing_lwm
-10
+10.000000
 SELECT local.innodb_adaptive_flushing_lwm;
 ERROR 42S02: Unknown table 'local' in field list
 SET global innodb_adaptive_flushing_lwm = 1;
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-1
+1.000000
 '#--------------------FN_DYNVARS_046_03------------------------#'
 SET @@global.innodb_adaptive_flushing_lwm = 1;
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-1
+1.000000
 SET @@global.innodb_adaptive_flushing_lwm = 60;
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-60
+60.000000
 SET @@global.innodb_adaptive_flushing_lwm = 70;
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-70
+70.000000
 '#--------------------FN_DYNVARS_046_04-------------------------#'
 SET @@global.innodb_adaptive_flushing_lwm = -1;
 Warnings:
 Warning	1292	Truncated incorrect innodb_adaptive_flushing_lwm value: '-1'
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-0
+0.000000
 SET @@global.innodb_adaptive_flushing_lwm = "T";
 ERROR 42000: Incorrect argument type to variable 'innodb_adaptive_flushing_lwm'
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-0
+0.000000
 SET @@global.innodb_adaptive_flushing_lwm = "Y";
 ERROR 42000: Incorrect argument type to variable 'innodb_adaptive_flushing_lwm'
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-0
+0.000000
 SET @@global.innodb_adaptive_flushing_lwm = 71;
 Warnings:
 Warning	1292	Truncated incorrect innodb_adaptive_flushing_lwm value: '71'
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-70
+70.000000
 '#----------------------FN_DYNVARS_046_05------------------------#'
 SELECT @@global.innodb_adaptive_flushing_lwm =
 VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
@@ -65,32 +65,32 @@ VARIABLE_VALUE
 1
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-70
+70.000000
 SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
 WHERE VARIABLE_NAME='innodb_adaptive_flushing_lwm';
 VARIABLE_VALUE
-70
+70.000000
 '#---------------------FN_DYNVARS_046_06-------------------------#'
 SET @@global.innodb_adaptive_flushing_lwm = OFF;
 ERROR 42000: Incorrect argument type to variable 'innodb_adaptive_flushing_lwm'
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-70
+70.000000
 SET @@global.innodb_adaptive_flushing_lwm = ON;
 ERROR 42000: Incorrect argument type to variable 'innodb_adaptive_flushing_lwm'
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-70
+70.000000
 '#---------------------FN_DYNVARS_046_07----------------------#'
 SET @@global.innodb_adaptive_flushing_lwm = TRUE;
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-1
+1.000000
 SET @@global.innodb_adaptive_flushing_lwm = FALSE;
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-0
+0.000000
 SET @@global.innodb_adaptive_flushing_lwm = @global_start_value;
 SELECT @@global.innodb_adaptive_flushing_lwm;
 @@global.innodb_adaptive_flushing_lwm
-10
+10.000000
diff --git a/mysql-test/suite/sys_vars/r/innodb_max_dirty_pages_pct_basic.result b/mysql-test/suite/sys_vars/r/innodb_max_dirty_pages_pct_basic.result
index eff72613102..d705624eb53 100644
--- a/mysql-test/suite/sys_vars/r/innodb_max_dirty_pages_pct_basic.result
+++ b/mysql-test/suite/sys_vars/r/innodb_max_dirty_pages_pct_basic.result
@@ -4,58 +4,64 @@ SELECT @global_start_value;
 75
 '#--------------------FN_DYNVARS_046_01------------------------#'
 SET @@global.innodb_max_dirty_pages_pct = 0;
-SET @@global.innodb_max_dirty_pages_pct = DEFAULT;
+Warnings:
+Warning	1292	Truncated incorrect innodb_max_dirty_pages_pct value: '0'
+SET @@global.innodb_max_dirty_pages_pct = @global_start_value;
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-75
+75.000000
 '#---------------------FN_DYNVARS_046_02-------------------------#'
 SET innodb_max_dirty_pages_pct = 1;
 ERROR HY000: Variable 'innodb_max_dirty_pages_pct' is a GLOBAL variable and should be set with SET GLOBAL
 SELECT @@innodb_max_dirty_pages_pct;
 @@innodb_max_dirty_pages_pct
-75
+75.000000
 SELECT local.innodb_max_dirty_pages_pct;
 ERROR 42S02: Unknown table 'local' in field list
 SET global innodb_max_dirty_pages_pct = 0;
+Warnings:
+Warning	1292	Truncated incorrect innodb_max_dirty_pages_pct value: '0'
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-0
+0.001000
 '#--------------------FN_DYNVARS_046_03------------------------#'
 SET @@global.innodb_max_dirty_pages_pct = 0;
+Warnings:
+Warning	1292	Truncated incorrect innodb_max_dirty_pages_pct value: '0'
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-0
+0.001000
 SET @@global.innodb_max_dirty_pages_pct = 1;
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-1
+1.000000
 SET @@global.innodb_max_dirty_pages_pct = 99;
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-99
+99.000000
 '#--------------------FN_DYNVARS_046_04-------------------------#'
 SET @@global.innodb_max_dirty_pages_pct = -1;
 Warnings:
 Warning	1292	Truncated incorrect innodb_max_dirty_pages_pct value: '-1'
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-0
+0.001000
 SET @@global.innodb_max_dirty_pages_pct = "T";
 ERROR 42000: Incorrect argument type to variable 'innodb_max_dirty_pages_pct'
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-0
+0.001000
 SET @@global.innodb_max_dirty_pages_pct = "Y";
 ERROR 42000: Incorrect argument type to variable 'innodb_max_dirty_pages_pct'
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-0
+0.001000
 SET @@global.innodb_max_dirty_pages_pct = 1001;
 Warnings:
 Warning	1292	Truncated incorrect innodb_max_dirty_pages_pct value: '1001'
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-99
+99.999000
 '#----------------------FN_DYNVARS_046_05------------------------#'
 SELECT @@global.innodb_max_dirty_pages_pct =
 VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
@@ -65,32 +71,34 @@ VARIABLE_VALUE
 1
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-99
+99.999000
 SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
 WHERE VARIABLE_NAME='innodb_max_dirty_pages_pct';
 VARIABLE_VALUE
-99
+99.999000
 '#---------------------FN_DYNVARS_046_06-------------------------#'
 SET @@global.innodb_max_dirty_pages_pct = OFF;
 ERROR 42000: Incorrect argument type to variable 'innodb_max_dirty_pages_pct'
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-99
+99.999000
 SET @@global.innodb_max_dirty_pages_pct = ON;
 ERROR 42000: Incorrect argument type to variable 'innodb_max_dirty_pages_pct'
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-99
+99.999000
 '#---------------------FN_DYNVARS_046_07----------------------#'
 SET @@global.innodb_max_dirty_pages_pct = TRUE;
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-1
+1.000000
 SET @@global.innodb_max_dirty_pages_pct = FALSE;
+Warnings:
+Warning	1292	Truncated incorrect innodb_max_dirty_pages_pct value: '0'
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-0
+0.001000
 SET @@global.innodb_max_dirty_pages_pct = @global_start_value;
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-75
+75.000000
diff --git a/mysql-test/suite/sys_vars/r/innodb_max_dirty_pages_pct_func.result b/mysql-test/suite/sys_vars/r/innodb_max_dirty_pages_pct_func.result
index 55de5adbc33..05aa3e5fd89 100644
--- a/mysql-test/suite/sys_vars/r/innodb_max_dirty_pages_pct_func.result
+++ b/mysql-test/suite/sys_vars/r/innodb_max_dirty_pages_pct_func.result
@@ -5,13 +5,13 @@ SET @@global.innodb_max_dirty_pages_pct = 80;
 'connection con1'
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-80
+80.000000
 SET @@global.innodb_max_dirty_pages_pct = 70;
 'connect (con2,localhost,root,,,,)'
 'connection con2'
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-70
+70.000000
 'connection default'
 'disconnect con2'
 'disconnect con1'
diff --git a/mysql-test/suite/sys_vars/r/innodb_max_dirty_pages_pct_lwm_basic.result b/mysql-test/suite/sys_vars/r/innodb_max_dirty_pages_pct_lwm_basic.result
index 82388cebc82..676ec103664 100644
--- a/mysql-test/suite/sys_vars/r/innodb_max_dirty_pages_pct_lwm_basic.result
+++ b/mysql-test/suite/sys_vars/r/innodb_max_dirty_pages_pct_lwm_basic.result
@@ -1,70 +1,70 @@
 SET @pct_lwm_start_value = @@global.innodb_max_dirty_pages_pct_lwm;
 SELECT @pct_lwm_start_value;
 @pct_lwm_start_value
-0
+0.001
 SET @pct_start_value = @@global.innodb_max_dirty_pages_pct;
 SELECT @pct_start_value;
 @pct_start_value
 75
 '#--------------------FN_DYNVARS_046_01------------------------#'
 SET @@global.innodb_max_dirty_pages_pct_lwm = 0;
-SET @@global.innodb_max_dirty_pages_pct_lwm = DEFAULT;
+SET @@global.innodb_max_dirty_pages_pct_lwm = @pct_lwm_start_value;
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-0
+0.001000
 '#---------------------FN_DYNVARS_046_02-------------------------#'
 SET innodb_max_dirty_pages_pct_lwm = 1;
 ERROR HY000: Variable 'innodb_max_dirty_pages_pct_lwm' is a GLOBAL variable and should be set with SET GLOBAL
 SELECT @@innodb_max_dirty_pages_pct_lwm;
 @@innodb_max_dirty_pages_pct_lwm
-0
+0.001000
 SELECT local.innodb_max_dirty_pages_pct_lwm;
 ERROR 42S02: Unknown table 'local' in field list
 SET global innodb_max_dirty_pages_pct_lwm = 0;
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-0
+0.000000
 '#--------------------FN_DYNVARS_046_03------------------------#'
 SET @@global.innodb_max_dirty_pages_pct_lwm = 0;
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-0
+0.000000
 SET @@global.innodb_max_dirty_pages_pct_lwm = @pct_start_value;
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-75
+75.000000
 '#--------------------FN_DYNVARS_046_04-------------------------#'
 SET @@global.innodb_max_dirty_pages_pct_lwm = -1;
 Warnings:
 Warning	1292	Truncated incorrect innodb_max_dirty_pages_pct_lwm value: '-1'
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-0
+0.000000
 SET @@global.innodb_max_dirty_pages_pct_lwm = "T";
 ERROR 42000: Incorrect argument type to variable 'innodb_max_dirty_pages_pct_lwm'
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-0
+0.000000
 SET @@global.innodb_max_dirty_pages_pct_lwm = "Y";
 ERROR 42000: Incorrect argument type to variable 'innodb_max_dirty_pages_pct_lwm'
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-0
+0.000000
 SET @@global.innodb_max_dirty_pages_pct_lwm = @pct_start_value + 1;
 Warnings:
 Warning	1210	innodb_max_dirty_pages_pct_lwm cannot be set higher than innodb_max_dirty_pages_pct.
-Warning	1210	Setting innodb_max_dirty_page_pct_lwm to 75
+Warning	1210	Setting innodb_max_dirty_page_pct_lwm to 75.000000
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-75
+75.000000
 SET @@global.innodb_max_dirty_pages_pct_lwm = 100;
 Warnings:
 Warning	1292	Truncated incorrect innodb_max_dirty_pages_pct_lwm value: '100'
 Warning	1210	innodb_max_dirty_pages_pct_lwm cannot be set higher than innodb_max_dirty_pages_pct.
-Warning	1210	Setting innodb_max_dirty_page_pct_lwm to 75
+Warning	1210	Setting innodb_max_dirty_page_pct_lwm to 75.000000
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-75
+75.000000
 '#----------------------FN_DYNVARS_046_05------------------------#'
 SELECT @@global.innodb_max_dirty_pages_pct_lwm =
 VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
@@ -74,36 +74,36 @@ VARIABLE_VALUE
 1
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-75
+75.000000
 SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
 WHERE VARIABLE_NAME='innodb_max_dirty_pages_pct_lwm';
 VARIABLE_VALUE
-75
+75.000000
 '#---------------------FN_DYNVARS_046_06-------------------------#'
 SET @@global.innodb_max_dirty_pages_pct_lwm = OFF;
 ERROR 42000: Incorrect argument type to variable 'innodb_max_dirty_pages_pct_lwm'
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-75
+75.000000
 SET @@global.innodb_max_dirty_pages_pct_lwm = ON;
 ERROR 42000: Incorrect argument type to variable 'innodb_max_dirty_pages_pct_lwm'
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-75
+75.000000
 '#---------------------FN_DYNVARS_046_07----------------------#'
 SET @@global.innodb_max_dirty_pages_pct_lwm = TRUE;
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-1
+1.000000
 SET @@global.innodb_max_dirty_pages_pct_lwm = FALSE;
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-0
+0.000000
 SET @@global.innodb_max_dirty_pages_pct = @pct_start_value;
 SELECT @@global.innodb_max_dirty_pages_pct;
 @@global.innodb_max_dirty_pages_pct
-75
+75.000000
 SET @@global.innodb_max_dirty_pages_pct_lwm = @pct_lwm_start_value;
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 @@global.innodb_max_dirty_pages_pct_lwm
-0
+0.001000
diff --git a/mysql-test/suite/sys_vars/t/innodb_max_dirty_pages_pct_basic.test b/mysql-test/suite/sys_vars/t/innodb_max_dirty_pages_pct_basic.test
index 7e70ed11351..5b4eaa41598 100644
--- a/mysql-test/suite/sys_vars/t/innodb_max_dirty_pages_pct_basic.test
+++ b/mysql-test/suite/sys_vars/t/innodb_max_dirty_pages_pct_basic.test
@@ -44,7 +44,7 @@ SELECT @global_start_value;
 ######################################################################## 
 
 SET @@global.innodb_max_dirty_pages_pct = 0;
-SET @@global.innodb_max_dirty_pages_pct = DEFAULT;
+SET @@global.innodb_max_dirty_pages_pct = @global_start_value;
 SELECT @@global.innodb_max_dirty_pages_pct;
 
 --echo '#---------------------FN_DYNVARS_046_02-------------------------#'
diff --git a/mysql-test/suite/sys_vars/t/innodb_max_dirty_pages_pct_lwm_basic.test b/mysql-test/suite/sys_vars/t/innodb_max_dirty_pages_pct_lwm_basic.test
index 7a6da2e6a08..d81b6cc725b 100644
--- a/mysql-test/suite/sys_vars/t/innodb_max_dirty_pages_pct_lwm_basic.test
+++ b/mysql-test/suite/sys_vars/t/innodb_max_dirty_pages_pct_lwm_basic.test
@@ -47,7 +47,7 @@ SELECT @pct_start_value;
 ########################################################################
 
 SET @@global.innodb_max_dirty_pages_pct_lwm = 0;
-SET @@global.innodb_max_dirty_pages_pct_lwm = DEFAULT;
+SET @@global.innodb_max_dirty_pages_pct_lwm = @pct_lwm_start_value;
 SELECT @@global.innodb_max_dirty_pages_pct_lwm;
 
 --echo '#---------------------FN_DYNVARS_046_02-------------------------#'
diff --git a/storage/innobase/buf/buf0buf.cc b/storage/innobase/buf/buf0buf.cc
index 6f00d2e43b5..18917259ed5 100644
--- a/storage/innobase/buf/buf0buf.cc
+++ b/storage/innobase/buf/buf0buf.cc
@@ -4937,22 +4937,22 @@ Returns the ratio in percents of modified pages in the buffer pool /
 database pages in the buffer pool.
 @return	modified page percentage ratio */
 UNIV_INTERN
-ulint
+double
 buf_get_modified_ratio_pct(void)
 /*============================*/
 {
-	ulint		ratio;
+	double		percentage = 0.0;
 	ulint		lru_len = 0;
 	ulint		free_len = 0;
 	ulint		flush_list_len = 0;
 
 	buf_get_total_list_len(&lru_len, &free_len, &flush_list_len);
 
-	ratio = (100 * flush_list_len) / (1 + lru_len + free_len);
+	percentage = (100.0 * flush_list_len) / (1.0 + lru_len + free_len);
 
 	/* 1 + is there to avoid division by zero */
 
-	return(ratio);
+	return(percentage);
 }
 
 /*******************************************************************//**
@@ -5165,6 +5165,8 @@ buf_print_io_instance(
 		"Database pages     %lu\n"
 		"Old database pages %lu\n"
 		"Modified db pages  %lu\n"
+		"Percent of dirty pages(LRU & free pages): %.3f\n"
+		"Max dirty pages percent: %.3f\n"
 		"Pending reads %lu\n"
 		"Pending writes: LRU %lu, flush list %lu, single page %lu\n",
 		pool_info->pool_size,
@@ -5172,6 +5174,9 @@ buf_print_io_instance(
 		pool_info->lru_len,
 		pool_info->old_lru_len,
 		pool_info->flush_list_len,
+		(((double) pool_info->flush_list_len) /
+		  (pool_info->lru_len + pool_info->free_list_len + 1.0)) * 100.0,
+		srv_max_buf_pool_modified_pct,
 		pool_info->n_pend_reads,
 		pool_info->n_pending_flush_lru,
 		pool_info->n_pending_flush_list,
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index f235981a892..1d13b23715c 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -3115,7 +3115,7 @@ innobase_change_buffering_inited_ok:
 				  " cannot be set higher than"
 				  " innodb_max_dirty_pages_pct.\n"
 				  "InnoDB: Setting"
-				  " innodb_max_dirty_pages_pct_lwm to %lu\n",
+				  " innodb_max_dirty_pages_pct_lwm to %lf\n",
 				  srv_max_buf_pool_modified_pct);
 
 		srv_max_dirty_pages_pct_lwm = srv_max_buf_pool_modified_pct;
@@ -14275,7 +14275,7 @@ innodb_max_dirty_pages_pct_update(
 	const void*			save)	/*!< in: immediate result
 						from check function */
 {
-	ulong	in_val = *static_cast<const ulong*>(save);
+	double	in_val = *static_cast<const double*>(save);
 	if (in_val < srv_max_dirty_pages_pct_lwm) {
 		push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
 				    ER_WRONG_ARGUMENTS,
@@ -14285,7 +14285,7 @@ innodb_max_dirty_pages_pct_update(
 		push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
 				    ER_WRONG_ARGUMENTS,
 				    "Lowering"
-				    " innodb_max_dirty_page_pct_lwm to %lu",
+				    " innodb_max_dirty_page_pct_lwm to %lf",
 				    in_val);
 
 		srv_max_dirty_pages_pct_lwm = in_val;
@@ -14309,7 +14309,7 @@ innodb_max_dirty_pages_pct_lwm_update(
 	const void*			save)	/*!< in: immediate result
 						from check function */
 {
-	ulong	in_val = *static_cast<const ulong*>(save);
+	double	in_val = *static_cast<const double*>(save);
 	if (in_val > srv_max_buf_pool_modified_pct) {
 		in_val = srv_max_buf_pool_modified_pct;
 		push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
@@ -14320,7 +14320,7 @@ innodb_max_dirty_pages_pct_lwm_update(
 		push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
 				    ER_WRONG_ARGUMENTS,
 				    "Setting innodb_max_dirty_page_pct_lwm"
-				    " to %lu",
+				    " to %lf",
 				    in_val);
 	}
 
@@ -16247,22 +16247,22 @@ static MYSQL_SYSVAR_STR(log_group_home_dir, srv_log_group_home_dir,
   PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
   "Path to InnoDB log files.", NULL, NULL, NULL);
 
-static MYSQL_SYSVAR_ULONG(max_dirty_pages_pct, srv_max_buf_pool_modified_pct,
+static MYSQL_SYSVAR_DOUBLE(max_dirty_pages_pct, srv_max_buf_pool_modified_pct,
   PLUGIN_VAR_RQCMDARG,
   "Percentage of dirty pages allowed in bufferpool.",
-  NULL, innodb_max_dirty_pages_pct_update, 75, 0, 99, 0);
+  NULL, innodb_max_dirty_pages_pct_update, 75.0, 0.001, 99.999, 0);
 
-static MYSQL_SYSVAR_ULONG(max_dirty_pages_pct_lwm,
+static MYSQL_SYSVAR_DOUBLE(max_dirty_pages_pct_lwm,
   srv_max_dirty_pages_pct_lwm,
   PLUGIN_VAR_RQCMDARG,
   "Percentage of dirty pages at which flushing kicks in.",
-  NULL, innodb_max_dirty_pages_pct_lwm_update, 0, 0, 99, 0);
+  NULL, innodb_max_dirty_pages_pct_lwm_update, 0.001, 0.000, 99.999, 0);
 
-static MYSQL_SYSVAR_ULONG(adaptive_flushing_lwm,
+static MYSQL_SYSVAR_DOUBLE(adaptive_flushing_lwm,
   srv_adaptive_flushing_lwm,
   PLUGIN_VAR_RQCMDARG,
   "Percentage of log capacity below which no adaptive flushing happens.",
-  NULL, NULL, 10, 0, 70, 0);
+  NULL, NULL, 10.0, 0.0, 70.0, 0);
 
 static MYSQL_SYSVAR_BOOL(adaptive_flushing, srv_adaptive_flushing,
   PLUGIN_VAR_NOCMDARG,
diff --git a/storage/innobase/include/buf0buf.h b/storage/innobase/include/buf0buf.h
index 3f2ac4980cf..31ec6b9ef8b 100644
--- a/storage/innobase/include/buf0buf.h
+++ b/storage/innobase/include/buf0buf.h
@@ -794,7 +794,7 @@ Returns the ratio in percents of modified pages in the buffer pool /
 database pages in the buffer pool.
 @return	modified page percentage ratio */
 UNIV_INTERN
-ulint
+double
 buf_get_modified_ratio_pct(void);
 /*============================*/
 /**********************************************************************//**
diff --git a/storage/innobase/include/srv0srv.h b/storage/innobase/include/srv0srv.h
index 7bf698f0a66..6df544f56d7 100644
--- a/storage/innobase/include/srv0srv.h
+++ b/storage/innobase/include/srv0srv.h
@@ -320,10 +320,10 @@ extern ulint	srv_win_file_flush_method;
 
 extern ulint	srv_max_n_open_files;
 
-extern ulong	srv_max_dirty_pages_pct;
-extern ulong	srv_max_dirty_pages_pct_lwm;
+extern double	srv_max_dirty_pages_pct;
+extern double	srv_max_dirty_pages_pct_lwm;
 
-extern ulong	srv_adaptive_flushing_lwm;
+extern double	srv_adaptive_flushing_lwm;
 extern ulong	srv_flushing_avg_loops;
 
 extern ulong	srv_force_recovery;
@@ -354,7 +354,7 @@ extern ibool	srv_use_atomic_writes;
 extern ibool	srv_use_posix_fallocate;
 #endif
 
-extern ulong	srv_max_buf_pool_modified_pct;
+extern double	srv_max_buf_pool_modified_pct;
 extern ulong	srv_max_purge_lag;
 extern ulong	srv_max_purge_lag_delay;
 
diff --git a/storage/innobase/srv/srv0srv.cc b/storage/innobase/srv/srv0srv.cc
index bc0e8e625e3..5b4f553cf42 100644
--- a/storage/innobase/srv/srv0srv.cc
+++ b/storage/innobase/srv/srv0srv.cc
@@ -276,12 +276,12 @@ in the buffer pool to all database pages in the buffer pool smaller than
 the following number. But it is not guaranteed that the value stays below
 that during a time of heavy update/insert activity. */
 
-UNIV_INTERN ulong	srv_max_buf_pool_modified_pct	= 75;
-UNIV_INTERN ulong	srv_max_dirty_pages_pct_lwm	= 50;
+UNIV_INTERN double	srv_max_buf_pool_modified_pct	= 75.0;
+UNIV_INTERN double	srv_max_dirty_pages_pct_lwm	= 50.0;
 
 /* This is the percentage of log capacity at which adaptive flushing,
 if enabled, will kick in. */
-UNIV_INTERN ulong	srv_adaptive_flushing_lwm	= 10;
+UNIV_INTERN double	srv_adaptive_flushing_lwm	= 10.0;
 
 /* Number of iterations over which adaptive flushing is averaged. */
 UNIV_INTERN ulong	srv_flushing_avg_loops		= 30;
diff --git a/storage/xtradb/buf/buf0buf.cc b/storage/xtradb/buf/buf0buf.cc
index 98b6787dda4..abb4a6f3ab9 100644
--- a/storage/xtradb/buf/buf0buf.cc
+++ b/storage/xtradb/buf/buf0buf.cc
@@ -5203,22 +5203,22 @@ Returns the ratio in percents of modified pages in the buffer pool /
 database pages in the buffer pool.
 @return	modified page percentage ratio */
 UNIV_INTERN
-ulint
+double
 buf_get_modified_ratio_pct(void)
 /*============================*/
 {
-	ulint		ratio;
+	double		percentage = 0.0;
 	ulint		lru_len = 0;
 	ulint		free_len = 0;
 	ulint		flush_list_len = 0;
 
 	buf_get_total_list_len(&lru_len, &free_len, &flush_list_len);
 
-	ratio = (100 * flush_list_len) / (1 + lru_len + free_len);
+	percentage = (100.0 * flush_list_len) / (1.0 + lru_len + free_len);
 
 	/* 1 + is there to avoid division by zero */
 
-	return(ratio);
+	return(percentage);
 }
 
 /*******************************************************************//**
@@ -5434,6 +5434,8 @@ buf_print_io_instance(
 		"Database pages          %lu\n"
 		"Old database pages      %lu\n"
 		"Modified db pages       %lu\n"
+		"Percent of dirty pages(LRU & free pages): %.3f\n"
+		"Max dirty pages percent: %.3f\n"
 		"Pending reads %lu\n"
 		"Pending writes: LRU %lu, flush list %lu, single page %lu\n",
 		pool_info->pool_size,
@@ -5442,6 +5444,9 @@ buf_print_io_instance(
 		pool_info->lru_len,
 		pool_info->old_lru_len,
 		pool_info->flush_list_len,
+		(((double) pool_info->flush_list_len) /
+		  (pool_info->lru_len + pool_info->free_list_len + 1.0)) * 100.0,
+		srv_max_buf_pool_modified_pct,
 		pool_info->n_pend_reads,
 		pool_info->n_pending_flush_lru,
 		pool_info->n_pending_flush_list,
diff --git a/storage/xtradb/handler/ha_innodb.cc b/storage/xtradb/handler/ha_innodb.cc
index bc23b65ada0..d559d38b735 100644
--- a/storage/xtradb/handler/ha_innodb.cc
+++ b/storage/xtradb/handler/ha_innodb.cc
@@ -3517,7 +3517,7 @@ innobase_change_buffering_inited_ok:
 				  " cannot be set higher than"
 				  " innodb_max_dirty_pages_pct.\n"
 				  "InnoDB: Setting"
-				  " innodb_max_dirty_pages_pct_lwm to %lu\n",
+				  " innodb_max_dirty_pages_pct_lwm to %lf\n",
 				  srv_max_buf_pool_modified_pct);
 
 		srv_max_dirty_pages_pct_lwm = srv_max_buf_pool_modified_pct;
@@ -15051,7 +15051,7 @@ innodb_max_dirty_pages_pct_update(
 	const void*			save)	/*!< in: immediate result
 						from check function */
 {
-	ulong	in_val = *static_cast<const ulong*>(save);
+	double	in_val = *static_cast<const double*>(save);
 	if (in_val < srv_max_dirty_pages_pct_lwm) {
 		push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
 				    ER_WRONG_ARGUMENTS,
@@ -15061,7 +15061,7 @@ innodb_max_dirty_pages_pct_update(
 		push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
 				    ER_WRONG_ARGUMENTS,
 				    "Lowering"
-				    " innodb_max_dirty_page_pct_lwm to %lu",
+				    " innodb_max_dirty_page_pct_lwm to %lf",
 				    in_val);
 
 		srv_max_dirty_pages_pct_lwm = in_val;
@@ -15085,7 +15085,7 @@ innodb_max_dirty_pages_pct_lwm_update(
 	const void*			save)	/*!< in: immediate result
 						from check function */
 {
-	ulong	in_val = *static_cast<const ulong*>(save);
+	double	in_val = *static_cast<const double*>(save);
 	if (in_val > srv_max_buf_pool_modified_pct) {
 		in_val = srv_max_buf_pool_modified_pct;
 		push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
@@ -15096,7 +15096,7 @@ innodb_max_dirty_pages_pct_lwm_update(
 		push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
 				    ER_WRONG_ARGUMENTS,
 				    "Setting innodb_max_dirty_page_pct_lwm"
-				    " to %lu",
+				    " to %lf",
 				    in_val);
 	}
 
@@ -17338,22 +17338,22 @@ static MYSQL_SYSVAR_ULONG(log_arch_expire_sec,
   "Expiration time for archived innodb transaction logs.",
   NULL, innodb_log_archive_expire_update, 0, 0, ~0UL, 0);
 
-static MYSQL_SYSVAR_ULONG(max_dirty_pages_pct, srv_max_buf_pool_modified_pct,
+static MYSQL_SYSVAR_DOUBLE(max_dirty_pages_pct, srv_max_buf_pool_modified_pct,
   PLUGIN_VAR_RQCMDARG,
   "Percentage of dirty pages allowed in bufferpool.",
-  NULL, innodb_max_dirty_pages_pct_update, 75, 0, 99, 0);
+  NULL, innodb_max_dirty_pages_pct_update, 75.0, 0.001, 99.999, 0);
 
-static MYSQL_SYSVAR_ULONG(max_dirty_pages_pct_lwm,
+static MYSQL_SYSVAR_DOUBLE(max_dirty_pages_pct_lwm,
   srv_max_dirty_pages_pct_lwm,
   PLUGIN_VAR_RQCMDARG,
   "Percentage of dirty pages at which flushing kicks in.",
-  NULL, innodb_max_dirty_pages_pct_lwm_update, 0, 0, 99, 0);
+  NULL, innodb_max_dirty_pages_pct_lwm_update, 0.001, 0.000, 99.999, 0);
 
-static MYSQL_SYSVAR_ULONG(adaptive_flushing_lwm,
+static MYSQL_SYSVAR_DOUBLE(adaptive_flushing_lwm,
   srv_adaptive_flushing_lwm,
   PLUGIN_VAR_RQCMDARG,
   "Percentage of log capacity below which no adaptive flushing happens.",
-  NULL, NULL, 10, 0, 70, 0);
+  NULL, NULL, 10.0, 0.0, 70.0, 0);
 
 static MYSQL_SYSVAR_BOOL(adaptive_flushing, srv_adaptive_flushing,
   PLUGIN_VAR_NOCMDARG,
diff --git a/storage/xtradb/include/buf0buf.h b/storage/xtradb/include/buf0buf.h
index 0f77404b1de..ad10b8d1eb2 100644
--- a/storage/xtradb/include/buf0buf.h
+++ b/storage/xtradb/include/buf0buf.h
@@ -792,7 +792,7 @@ Returns the ratio in percents of modified pages in the buffer pool /
 database pages in the buffer pool.
 @return	modified page percentage ratio */
 UNIV_INTERN
-ulint
+double
 buf_get_modified_ratio_pct(void);
 /*============================*/
 /**********************************************************************//**
diff --git a/storage/xtradb/include/srv0srv.h b/storage/xtradb/include/srv0srv.h
index 14f2d68ff45..ed7ced02674 100644
--- a/storage/xtradb/include/srv0srv.h
+++ b/storage/xtradb/include/srv0srv.h
@@ -388,10 +388,10 @@ extern ulint	srv_win_file_flush_method;
 
 extern ulint	srv_max_n_open_files;
 
-extern ulong	srv_max_dirty_pages_pct;
-extern ulong	srv_max_dirty_pages_pct_lwm;
+extern double	srv_max_dirty_pages_pct;
+extern double	srv_max_dirty_pages_pct_lwm;
 
-extern ulong	srv_adaptive_flushing_lwm;
+extern double	srv_adaptive_flushing_lwm;
 extern ulong	srv_flushing_avg_loops;
 
 extern ulong	srv_force_recovery;
@@ -423,7 +423,7 @@ extern ulong	srv_checksum_algorithm;
 
 extern ulong	srv_log_arch_expire_sec;
 
-extern ulong	srv_max_buf_pool_modified_pct;
+extern double	srv_max_buf_pool_modified_pct;
 extern ulong	srv_max_purge_lag;
 extern ulong	srv_max_purge_lag_delay;
 
diff --git a/storage/xtradb/srv/srv0srv.cc b/storage/xtradb/srv/srv0srv.cc
index e0e15202991..6ef788481c7 100644
--- a/storage/xtradb/srv/srv0srv.cc
+++ b/storage/xtradb/srv/srv0srv.cc
@@ -347,12 +347,12 @@ in the buffer pool to all database pages in the buffer pool smaller than
 the following number. But it is not guaranteed that the value stays below
 that during a time of heavy update/insert activity. */
 
-UNIV_INTERN ulong	srv_max_buf_pool_modified_pct	= 75;
-UNIV_INTERN ulong	srv_max_dirty_pages_pct_lwm	= 50;
+UNIV_INTERN double	srv_max_buf_pool_modified_pct	= 75.0;
+UNIV_INTERN double	srv_max_dirty_pages_pct_lwm	= 50.0;
 
 /* This is the percentage of log capacity at which adaptive flushing,
 if enabled, will kick in. */
-UNIV_INTERN ulong	srv_adaptive_flushing_lwm	= 10;
+UNIV_INTERN double	srv_adaptive_flushing_lwm	= 10.0;
 
 /* Number of iterations over which adaptive flushing is averaged. */
 UNIV_INTERN ulong	srv_flushing_avg_loops		= 30;