MDEV-16711 Crash in Field_blob::store() while reading statistics

          for the small InnoDB table

This bug was introduced by the patch 6c414fcf89510215d6d3466eb9992d444eadae89.
The patch has not taken into account that some objects of the Field_* types
are created only for TABLE_SHARE and the field 'table' is set to NULL
for them. In particular such are objects created to store statistical
min/max values for columns.

4 files changed, 101 insertions, 47 deletions

diff --git a/mysql-test/r/stat_tables.result b/mysql-test/r/stat_tables.result
index 0ee0d698bcc..279c09ff44f 100644
--- a/mysql-test/r/stat_tables.result
+++ b/mysql-test/r/stat_tables.result
@@ -518,6 +518,34 @@ drop database db2;
 drop table t1;
 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	Warning	Engine-independent statistics are not collected for column 't'
+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
+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;
+#
 # MDEV-16760: CREATE OR REPLACE TABLE after ANALYZE TABLE
 #
 SET use_stat_tables= PREFERABLY;
@@ -543,30 +571,18 @@ db_name	table_name	column_name	min_value	max_value	nulls_ratio	avg_length	avg_fr
 DROP TABLE t1;
 set use_stat_tables=@save_use_stat_tables;
 #
-# MDEV-16757: manual addition of min/max statistics for BLOB
+# MDEV-16711:CREATE OR REPLACE TABLE introducing BLOB column
 #
 SET use_stat_tables= PREFERABLY;
-CREATE TABLE t1 (pk INT PRIMARY KEY, t TEXT);
+CREATE TABLE t1 (pk INT PRIMARY KEY, t CHAR(60));
 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	Warning	Engine-independent statistics are not collected for column 't'
 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
-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
+CREATE OR REPLACE TABLE t1 (pk INT PRIMARY KEY, t TEXT);
+SELECT MAX(pk) FROM t1;
+MAX(pk)
+NULL
 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 b0319508ede..d551afdb282 100644
--- a/mysql-test/r/stat_tables_innodb.result
+++ b/mysql-test/r/stat_tables_innodb.result
@@ -545,6 +545,34 @@ drop database db2;
 drop table t1;
 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	Warning	Engine-independent statistics are not collected for column 't'
+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
+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;
+#
 # MDEV-16760: CREATE OR REPLACE TABLE after ANALYZE TABLE
 #
 SET use_stat_tables= PREFERABLY;
@@ -570,31 +598,19 @@ db_name	table_name	column_name	min_value	max_value	nulls_ratio	avg_length	avg_fr
 DROP TABLE t1;
 set use_stat_tables=@save_use_stat_tables;
 #
-# MDEV-16757: manual addition of min/max statistics for BLOB
+# MDEV-16711:CREATE OR REPLACE TABLE introducing BLOB column
 #
 SET use_stat_tables= PREFERABLY;
-CREATE TABLE t1 (pk INT PRIMARY KEY, t TEXT);
+CREATE TABLE t1 (pk INT PRIMARY KEY, t CHAR(60));
 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	Warning	Engine-independent statistics are not collected for column 't'
 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
-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
+CREATE OR REPLACE TABLE t1 (pk INT PRIMARY KEY, t TEXT);
+SELECT MAX(pk) FROM t1;
+MAX(pk)
+NULL
 DROP TABLE t1;
 set use_stat_tables=@save_use_stat_tables;
 set optimizer_switch=@save_optimizer_switch_for_stat_tables_test;
diff --git a/mysql-test/t/stat_tables.test b/mysql-test/t/stat_tables.test
index 7660acf6e42..cfe9255891a 100644
--- a/mysql-test/t/stat_tables.test
+++ b/mysql-test/t/stat_tables.test
@@ -308,6 +308,30 @@ drop table t1;
 set use_stat_tables=@save_use_stat_tables;
 
 --echo #
+--echo # MDEV-16757: manual addition of min/max statistics for BLOB
+--echo #
+
+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;
+--sorted_result
+SELECT * FROM mysql.column_stats;
+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);
+--sorted_result
+SELECT * FROM mysql.column_stats;
+
+SELECT pk FROM t1;
+
+DROP TABLE t1;
+
+set use_stat_tables=@save_use_stat_tables;
+
+--echo #
 --echo # MDEV-16760: CREATE OR REPLACE TABLE after ANALYZE TABLE
 --echo #
 
@@ -328,24 +352,17 @@ DROP TABLE t1;
 set use_stat_tables=@save_use_stat_tables;
 
 --echo #
---echo # MDEV-16757: manual addition of min/max statistics for BLOB
+--echo # MDEV-16711:CREATE OR REPLACE TABLE introducing BLOB column
 --echo #
 
 SET use_stat_tables= PREFERABLY;
 
-CREATE TABLE t1 (pk INT PRIMARY KEY, t TEXT);
+CREATE TABLE t1 (pk INT PRIMARY KEY, t CHAR(60));
 INSERT INTO t1 VALUES (1,'foo'),(2,'bar');
 ANALYZE TABLE t1;
---sorted_result
-SELECT * FROM mysql.column_stats;
-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);
---sorted_result
-SELECT * FROM mysql.column_stats;
+CREATE OR REPLACE TABLE t1 (pk INT PRIMARY KEY, t TEXT);
 
-SELECT pk FROM t1;
+SELECT MAX(pk) FROM t1;
 
 DROP TABLE t1;
 
diff --git a/sql/field.cc b/sql/field.cc
index 50edec4a1db..f4717de7b35 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -7924,6 +7924,11 @@ int Field_blob::store(const char *from,uint length,CHARSET_INFO *cs)
     return 0;
   }
 
+  /*
+    For min/max fields of statistical data 'table' is set to NULL.
+    It could not be otherwise as this data is shared by many instances
+    of the same base table.
+  */
   if (table && table->blob_storage)    // GROUP_CONCAT with ORDER BY | DISTINCT
   {
     DBUG_ASSERT(!f_is_hex_escape(flags));