DROP TABLE if exists t1;
select @@global.innodb_stats_persistent;
@@global.innodb_stats_persistent
0
set global innodb_defragment_stats_accuracy = 80;
CREATE TABLE t1 (a INT NOT NULL PRIMARY KEY AUTO_INCREMENT, b VARCHAR(256), c INT, KEY second(a, b),KEY third(c)) ENGINE=INNODB;
SET @@global.innodb_defragment_n_pages = 20;
select count(*) from t1;
count(*)
20000
select count(*) from t1 force index (second);
count(*)
20000
select count(*) from t1 force index (third);
count(*)
20000
select count(*) from t1;
count(*)
15800
select count(*) from t1 force index (second);
count(*)
15800
select count(*) from t1 force index (third);
count(*)
15800
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
optimize table t1;;
INSERT INTO t1 VALUES (400000, REPEAT('A', 256),300000);;
INSERT INTO t1 VALUES (500000, REPEAT('A', 256),400000);;
DELETE FROM t1 where a between 1 and 100;;
UPDATE t1 SET c = c + 1 where c between 2000 and 8000;;
optimize table t1;
Table	Op	Msg_type	Msg_text
test.t1	optimize	status	OK
select count(*) from t1;
count(*)
15723
select count(*) from t1 force index (second);
count(*)
15723
select count(*) from t1 force index (third);
count(*)
15723
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
1
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
drop table t1;