Make innodb.innodb_defrag_stats more deterministic

Let us mask the actual values of the defragmentation-related fields,
because they may vary. Also, remove the dependency on purge,
and instead delete records by a ROLLBACK of INSERT.

mysql-test/suite/innodb/t/innodb_defrag_stats.test

@@ -8,77 +8,65 @@ SET GLOBAL innodb_defragment_stats_accuracy = 20;
 DELETE FROM mysql.innodb_index_stats;
 
 --echo # Create table.
-CREATE TABLE t1 (a INT NOT NULL PRIMARY KEY AUTO_INCREMENT, b VARCHAR(256), KEY SECOND(a, b)) ENGINE=INNODB;
+CREATE TABLE t1 (a INT PRIMARY KEY AUTO_INCREMENT, b VARCHAR(256),
+                 KEY SECOND(a, b)) ENGINE=INNODB STATS_PERSISTENT=0;
 
-INSERT INTO t1 SELECT seq, REPEAT('A', 256) FROM seq_1_to_1024;
+INSERT INTO t1 SELECT 100*FLOOR(seq/70)+seq%70, REPEAT('A', 256)
+FROM seq_1_to_1024;
 
 --echo # 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');
-select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_pages_freed');
-select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_leaf_pages_defrag');
-
-INSERT INTO t1 SELECT seq, REPEAT('A', 256) FROM seq_1025_to_2048;
+SELECT * FROM mysql.innodb_index_stats;
 
---echo # 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');
-select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_pages_freed');
-select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_leaf_pages_defrag');
+INSERT INTO t1 SELECT 100*FLOOR(seq/70)+seq%70, REPEAT('A', 256)
+FROM seq_1025_to_1433;
 
---echo # Delete some rows.
 BEGIN;
 let $num_delete = 20;
 while ($num_delete)
 {
-    let $j = 100 * $num_delete;
-    eval delete from t1 where a between $j and $j + 30;
+    eval INSERT INTO t1 SELECT 100*$num_delete+seq, REPEAT('A', 256)
+    FROM seq_70_to_99;
     dec $num_delete;
 }
-COMMIT;
+ROLLBACK;
+
+SELECT @@GLOBAL.innodb_force_recovery<2 "have background defragmentation";
+
+# Wait for defrag_pool to be processed.
 
-select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_page_split');
-select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_pages_freed');
-select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_leaf_pages_defrag');
+let $wait_timeout=30;
+let $wait_condition = SELECT COUNT(*)>0 FROM mysql.innodb_index_stats;
+--source include/wait_condition.inc
+
+--sorted_result
+SELECT table_name, index_name, stat_name FROM mysql.innodb_index_stats;
 
 optimize table t1;
 
-select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_page_split');
-select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_pages_freed');
-select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_leaf_pages_defrag');
+--sorted_result
+SELECT table_name, index_name, stat_name FROM mysql.innodb_index_stats;
 
 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');
-select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_pages_freed');
-select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_leaf_pages_defrag');
-
+--sorted_result
+SELECT table_name, index_name, stat_name FROM mysql.innodb_index_stats;
 
 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');
-select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_pages_freed');
-select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_leaf_pages_defrag');
-
+--sorted_result
+SELECT stat_name FROM mysql.innodb_index_stats WHERE table_name='t1';
 
 --echo # 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');
-select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_pages_freed');
-select count(stat_value) = 0 from mysql.innodb_index_stats where table_name like '%t1%' and  stat_name in ('n_leaf_pages_defrag');
-
-select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t2%' and  stat_name in ('n_page_split');
-select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t2%' and  stat_name in ('n_pages_freed');
-select count(stat_value) > 0 from mysql.innodb_index_stats where table_name like '%t2%' and  stat_name in ('n_leaf_pages_defrag');
+--sorted_result
+SELECT table_name, index_name, stat_name FROM mysql.innodb_index_stats;
 
 --echo # Drop index should cause stats drop, but will not.
 drop index SECOND on t2;
 
---sorted_result
-SELECT stat_name, stat_value>0 FROM mysql.innodb_index_stats
-WHERE table_name like '%t2%' AND index_name='SECOND';
-
 --echo #
 --echo # MDEV-26636: Statistics must not be written for temporary tables
 --echo #
@@ -89,13 +77,13 @@ INSERT INTO t SELECT seq, '' FROM seq_1_to_100;
 
 --source include/restart_mysqld.inc
 
-SELECT * FROM mysql.innodb_index_stats where table_name like '%t1%';
-
 --sorted_result
-SELECT table_name, index_name, stat_name, stat_value>0
-FROM mysql.innodb_index_stats;
+SELECT table_name, index_name, stat_name FROM mysql.innodb_index_stats;
 
 --echo # Clean up
+# Starting with 10.6, DROP TABLE will not touch persistent statistics
+# (not defragmentation statistics either) if the table has none!
+ALTER TABLE t2 STATS_PERSISTENT=1;
 DROP TABLE t2;
 
 SELECT * FROM mysql.innodb_index_stats;