MDEV-16757 Memory leak after adding manually min/max statistical data

           for blob column

ANALYZE TABLE <table> does not collect statistical data on min/max values
for BLOB columns of <table>. However these values can be added into
mysql.column_stats manually by executing proper statements.
Unfortunately this led to a memory leak because the memory allocated
for these values was never freed.
This patch provides the server with a function to free memory allocated
for min/max statistical values of BLOB types.

2 files changed, 56 insertions, 0 deletions

diff --git a/mysql-test/r/stat_tables.result b/mysql-test/r/stat_tables.result
index 4a608089d7d..e6b675060a5 100644
--- a/mysql-test/r/stat_tables.result
+++ b/mysql-test/r/stat_tables.result
@@ -524,3 +524,31 @@ SELECT CONVERT_TZ( '1991-09-20 10:11:02', '+00:00', 'GMT' );
 CONVERT_TZ( '1991-09-20 10:11:02', '+00:00', 'GMT' )
 NULL
 set use_stat_tables=@save_use_stat_tables;
+#
+# MDEV-16757: manual addition of min/max statistics for BLOB
+#
+SET use_stat_tables= PREFERABLY;
+CREATE TABLE t1 (pk INT PRIMARY KEY, t TEXT);
+INSERT INTO t1 VALUES (1,'foo'),(2,'bar');
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT * FROM mysql.column_stats;
+db_name	table_name	column_name	min_value	max_value	nulls_ratio	avg_length	avg_frequency	hist_size	hist_type	histogram
+test	t1	pk	1	2	0.0000	4.0000	1.0000	0	NULL	NULL
+test	t1	t	NULL	NULL	0.0000	3.0000	NULL	NULL	NULL	NULL
+DELETE FROM mysql.column_stats
+WHERE db_name='test' AND table_name='t1' AND column_name='t';
+INSERT INTO mysql.column_stats VALUES
+('test','t1','t','bar','foo', 0.0, 3.0, 1.0, 0, NULL, NULL);
+SELECT * FROM mysql.column_stats;
+db_name	table_name	column_name	min_value	max_value	nulls_ratio	avg_length	avg_frequency	hist_size	hist_type	histogram
+test	t1	pk	1	2	0.0000	4.0000	1.0000	0	NULL	NULL
+test	t1	t	bar	foo	0.0000	3.0000	1.0000	0	NULL	NULL
+SELECT pk FROM t1;
+pk
+1
+2
+DROP TABLE t1;
+set use_stat_tables=@save_use_stat_tables;
diff --git a/mysql-test/r/stat_tables_innodb.result b/mysql-test/r/stat_tables_innodb.result
index 87049b228e5..04d73868cfb 100644
--- a/mysql-test/r/stat_tables_innodb.result
+++ b/mysql-test/r/stat_tables_innodb.result
@@ -551,5 +551,33 @@ SELECT CONVERT_TZ( '1991-09-20 10:11:02', '+00:00', 'GMT' );
 CONVERT_TZ( '1991-09-20 10:11:02', '+00:00', 'GMT' )
 NULL
 set use_stat_tables=@save_use_stat_tables;
+#
+# MDEV-16757: manual addition of min/max statistics for BLOB
+#
+SET use_stat_tables= PREFERABLY;
+CREATE TABLE t1 (pk INT PRIMARY KEY, t TEXT);
+INSERT INTO t1 VALUES (1,'foo'),(2,'bar');
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT * FROM mysql.column_stats;
+db_name	table_name	column_name	min_value	max_value	nulls_ratio	avg_length	avg_frequency	hist_size	hist_type	histogram
+test	t1	pk	1	2	0.0000	4.0000	1.0000	0	NULL	NULL
+test	t1	t	NULL	NULL	0.0000	3.0000	NULL	NULL	NULL	NULL
+DELETE FROM mysql.column_stats
+WHERE db_name='test' AND table_name='t1' AND column_name='t';
+INSERT INTO mysql.column_stats VALUES
+('test','t1','t','bar','foo', 0.0, 3.0, 1.0, 0, NULL, NULL);
+SELECT * FROM mysql.column_stats;
+db_name	table_name	column_name	min_value	max_value	nulls_ratio	avg_length	avg_frequency	hist_size	hist_type	histogram
+test	t1	pk	1	2	0.0000	4.0000	1.0000	0	NULL	NULL
+test	t1	t	bar	foo	0.0000	3.0000	1.0000	0	NULL	NULL
+SELECT pk FROM t1;
+pk
+1
+2
+DROP TABLE t1;
+set use_stat_tables=@save_use_stat_tables;
 set optimizer_switch=@save_optimizer_switch_for_stat_tables_test;
 SET SESSION STORAGE_ENGINE=DEFAULT;