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SET GLOBAL innodb_defragment_stats_accuracy = 20;
DELETE FROM mysql.innodb_index_stats;
# Create table.
CREATE TABLE t1 (a INT NOT NULL PRIMARY KEY AUTO_INCREMENT, b VARCHAR(256), KEY SECOND(a, b)) ENGINE=INNODB;
INSERT INTO t1 SELECT seq, REPEAT('A', 256) FROM seq_1_to_1024;
# Not enough page splits to trigger persistent stats write yet.
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_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_leaf_pages_defrag');
count(stat_value) = 0
1
INSERT INTO t1 SELECT seq, REPEAT('A', 256) FROM seq_1025_to_2048;
# Persistent stats recorded.
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_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_leaf_pages_defrag');
count(stat_value) > 0
1
# Delete some rows.
BEGIN;
delete from t1 where a between 100 * 20 and 100 * 20 + 30;
delete from t1 where a between 100 * 19 and 100 * 19 + 30;
delete from t1 where a between 100 * 18 and 100 * 18 + 30;
delete from t1 where a between 100 * 17 and 100 * 17 + 30;
delete from t1 where a between 100 * 16 and 100 * 16 + 30;
delete from t1 where a between 100 * 15 and 100 * 15 + 30;
delete from t1 where a between 100 * 14 and 100 * 14 + 30;
delete from t1 where a between 100 * 13 and 100 * 13 + 30;
delete from t1 where a between 100 * 12 and 100 * 12 + 30;
delete from t1 where a between 100 * 11 and 100 * 11 + 30;
delete from t1 where a between 100 * 10 and 100 * 10 + 30;
delete from t1 where a between 100 * 9 and 100 * 9 + 30;
delete from t1 where a between 100 * 8 and 100 * 8 + 30;
delete from t1 where a between 100 * 7 and 100 * 7 + 30;
delete from t1 where a between 100 * 6 and 100 * 6 + 30;
delete from t1 where a between 100 * 5 and 100 * 5 + 30;
delete from t1 where a between 100 * 4 and 100 * 4 + 30;
delete from t1 where a between 100 * 3 and 100 * 3 + 30;
delete from t1 where a between 100 * 2 and 100 * 2 + 30;
delete from t1 where a between 100 * 1 and 100 * 1 + 30;
COMMIT;
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_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_leaf_pages_defrag');
count(stat_value) > 0
1
optimize table t1;
Table Op Msg_type Msg_text
test.t1 optimize status OK
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_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_leaf_pages_defrag');
count(stat_value) > 0
1
set global innodb_defragment_stats_accuracy = 40;
INSERT INTO t1 (b) SELECT b from t1;
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_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_leaf_pages_defrag');
count(stat_value) > 0
1
INSERT INTO t1 (b) SELECT b from t1;
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_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_leaf_pages_defrag');
count(stat_value) > 0
1
# Table rename should cause stats rename.
rename table t1 to t2;
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_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_leaf_pages_defrag');
count(stat_value) = 0
1
select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t2%' 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 '%t2%' 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 '%t2%' and stat_name in ('n_leaf_pages_defrag');
count(stat_value) > 0
1
# Drop index should cause stats drop, but will not.
drop index SECOND on t2;
SELECT stat_name, stat_value>0 FROM mysql.innodb_index_stats
WHERE table_name like '%t2%' AND index_name='SECOND';
stat_name stat_value>0
n_leaf_pages_defrag 1
n_leaf_pages_reserved 1
n_page_split 1
n_pages_freed 1
#
# MDEV-26636: Statistics must not be written for temporary tables
#
SET GLOBAL innodb_defragment_stats_accuracy = 1;
CREATE TEMPORARY TABLE t (a INT PRIMARY KEY, c CHAR(255) NOT NULL)
ENGINE=InnoDB;
INSERT INTO t SELECT seq, '' FROM seq_1_to_100;
# restart
SELECT * FROM mysql.innodb_index_stats where table_name like '%t1%';
database_name table_name index_name last_update stat_name stat_value sample_size stat_description
SELECT table_name, index_name, stat_name, stat_value>0
FROM mysql.innodb_index_stats;
table_name index_name stat_name stat_value>0
t2 PRIMARY n_leaf_pages_defrag 1
t2 PRIMARY n_leaf_pages_reserved 1
t2 PRIMARY n_page_split 1
t2 PRIMARY n_pages_freed 1
t2 SECOND n_leaf_pages_defrag 1
t2 SECOND n_leaf_pages_reserved 1
t2 SECOND n_page_split 1
t2 SECOND n_pages_freed 1
# Clean up
DROP TABLE t2;
SELECT * FROM mysql.innodb_index_stats;
database_name table_name index_name last_update stat_name stat_value sample_size stat_description
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