set global innodb_defragment_stats_accuracy = 80;
CREATE TABLE t1 (a INT NOT NULL PRIMARY KEY AUTO_INCREMENT, b VARCHAR(256), KEY SECOND(a, b)) ENGINE=INNODB;
optimize table t1;
Table	Op	Msg_type	Msg_text
test.t1	optimize	status	OK
INSERT INTO t1 VALUES (100000, REPEAT('A', 256));
INSERT INTO t1 VALUES (200000, REPEAT('A', 256));
INSERT INTO t1 VALUES (300000, REPEAT('A', 256));
INSERT INTO t1 VALUES (400000, REPEAT('A', 256));
optimize table t1;
Table	Op	Msg_type	Msg_text
test.t1	optimize	status	OK
create procedure defragment()
begin
set @i = 0;
repeat
set @i = @i + 1;
optimize table t1;
until @i = 3 end repeat;
end //
select count(stat_value) from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_pages_freed');
count(stat_value)
0
select count(stat_value) from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_page_split');
count(stat_value)
2
select count(stat_value) from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_leaf_pages_defrag');
count(stat_value)
2
select count(*) from t1;
count(*)
10004
connect  con1,localhost,root,,test,$MASTER_MYPORT,$MASTER_MYSOCK;
connection con1;
call defragment();
connection default;
connection con1;
connection default;
disconnect con1;
optimize table t1;
Table	Op	Msg_type	Msg_text
test.t1	optimize	status	OK
select count(*) from t1;
count(*)
7904
select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_pages_freed');
count(stat_value) = 0
0
select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_page_split');
count(stat_value) > 0
1
select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_leaf_pages_defrag');
count(stat_value) > 0
1
select count(*) from t1 force index (second);
count(*)
7904
select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and index_name = 'second' and stat_name  in ('n_pages_freed');
count(stat_value) = 0
1
select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and index_name = 'second' and stat_name  in ('n_page_split');
count(stat_value) = 0
1
select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and index_name = 'second' and stat_name  in ('n_leaf_pages_defrag');
count(stat_value) = 0
1
SET @@global.innodb_defragment_n_pages = 3;
optimize table t1;
Table	Op	Msg_type	Msg_text
test.t1	optimize	status	OK
select count(stat_value) < 3 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_pages_freed');
count(stat_value) < 3
1
select count(stat_value) < 3 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_page_split');
count(stat_value) < 3
1
select count(stat_value) < 3 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_leaf_pages_defrag');
count(stat_value) < 3
1
select count(*) from t1;
count(*)
6904
select count(stat_value) < 3 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_pages_freed');
count(stat_value) < 3
1
select count(stat_value) < 3 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_page_split');
count(stat_value) < 3
1
select count(stat_value) < 3 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_leaf_pages_defrag');
count(stat_value) < 3
1
select count(*) from t1 force index (second);
count(*)
6904
select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and index_name = 'second' and stat_name  in ('n_pages_freed');
count(stat_value) = 0
1
select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and index_name = 'second' and stat_name  in ('n_page_split');
count(stat_value) = 0
1
select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and index_name = 'second' and stat_name  in ('n_leaf_pages_defrag');
count(stat_value) = 0
1
SET @@global.innodb_defragment_n_pages = 10;
optimize table t1;
Table	Op	Msg_type	Msg_text
test.t1	optimize	status	OK
select count(stat_value) > 1 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_pages_freed');
count(stat_value) > 1
1
select count(stat_value) > 1 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_page_split');
count(stat_value) > 1
1
select count(stat_value) > 1 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name  in ('n_leaf_pages_defrag');
count(stat_value) > 1
1
select count(*) from t1 force index (second);
count(*)
6904
select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and index_name = 'second' and stat_name  in ('n_pages_freed');
count(stat_value) = 0
1
select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and index_name = 'second' and stat_name  in ('n_page_split');
count(stat_value) = 0
1
select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and index_name = 'second' and stat_name  in ('n_leaf_pages_defrag');
count(stat_value) = 0
1
DROP PROCEDURE defragment;
DROP TABLE t1;