MDEV-17778: Alter table leads to a truncation warning with ANALYZE command

Alter statement changed the THD structure by setting the value to FIELD_CHECK_WARN
and then not resetting it back. This led ANALYZE to throw a warning which previously
it didn't.

mysql-test/main/alter_table.result

@@ -2469,3 +2469,24 @@ DROP TABLE t1;
 #
 # End of 10.2 tests
 #
+#
+# MDEV-17778: Alter table leads to a truncation warning with ANALYZE command
+#
+set @save_use_stat_tables= @@use_stat_tables;
+set @save_optimizer_use_condition_selectivity= @@optimizer_use_condition_selectivity;
+set @@optimizer_use_condition_selectivity=4;
+set @@use_stat_tables=PREFERABLY;
+create table t1 (a int)engine=InnoDB;
+insert into t1 values (1),(1),(2),(3);
+analyze table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+alter table t1 change a b int;
+analyze table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+set @@use_stat_tables= @save_use_stat_tables;
+set @@optimizer_use_condition_selectivity= @save_optimizer_use_condition_selectivity;
+drop table t1;

mysql-test/main/alter_table.test

@@ -2021,3 +2021,22 @@ DROP TABLE t1;
 --echo #
 --echo # End of 10.2 tests
 --echo #
+
+--echo #
+--echo # MDEV-17778: Alter table leads to a truncation warning with ANALYZE command
+--echo #
+
+set @save_use_stat_tables= @@use_stat_tables;
+set @save_optimizer_use_condition_selectivity= @@optimizer_use_condition_selectivity;
+set @@optimizer_use_condition_selectivity=4;
+set @@use_stat_tables=PREFERABLY;
+
+create table t1 (a int)engine=InnoDB;
+insert into t1 values (1),(1),(2),(3);
+
+analyze table t1;
+alter table t1 change a b int;
+analyze table t1;
+set @@use_stat_tables= @save_use_stat_tables;
+set @@optimizer_use_condition_selectivity= @save_optimizer_use_condition_selectivity;
+drop table t1;

mysql-test/main/selectivity_innodb.result

@@ -1150,7 +1150,6 @@ alter table t1 change column a a int;
 analyze table t1;
 Table	Op	Msg_type	Msg_text
 test.t1	analyze	status	Engine-independent statistics collected
-test.t1	analyze	Note	Data truncated for column 'avg_frequency' at row 1
 test.t1	analyze	status	OK
 flush table t1;
 explain extended select * from t1 where a between 5 and 7;

mysql-test/main/statistics.result

@@ -1086,9 +1086,6 @@ test	t2	idx4	3	1.1304
 ANALYZE TABLE t2 PERSISTENT FOR COLUMNS() INDEXES ALL;
 Table	Op	Msg_type	Msg_text
 test.t2	analyze	status	Engine-independent statistics collected
-test.t2	analyze	Note	Data truncated for column 'avg_frequency' at row 1
-test.t2	analyze	Note	Data truncated for column 'avg_frequency' at row 1
-test.t2	analyze	Note	Data truncated for column 'avg_frequency' at row 1
 test.t2	analyze	status	OK
 SELECT * FROM mysql.index_stats ORDER BY index_name, prefix_arity, table_name;
 db_name	table_name	index_name	prefix_arity	avg_frequency
@@ -1149,11 +1146,6 @@ test	t2	idx4	4	1.0000
 ANALYZE TABLE t2 PERSISTENT FOR COLUMNS ALL INDEXES ALL;
 Table	Op	Msg_type	Msg_text
 test.t2	analyze	status	Engine-independent statistics collected
-test.t2	analyze	Note	Data truncated for column 'avg_length' at row 1
-test.t2	analyze	Note	Data truncated for column 'avg_frequency' at row 1
-test.t2	analyze	Note	Data truncated for column 'avg_frequency' at row 1
-test.t2	analyze	Note	Data truncated for column 'avg_frequency' at row 1
-test.t2	analyze	Note	Data truncated for column 'avg_frequency' at row 1
 test.t2	analyze	status	OK
 SELECT * FROM mysql.index_stats ORDER BY index_name, prefix_arity, table_name;
 db_name	table_name	index_name	prefix_arity	avg_frequency
@@ -1179,8 +1171,6 @@ test	t2	idx3	1	8.5000
 ANALYZE TABLE t2 PERSISTENT FOR COLUMNS() INDEXES ALL;
 Table	Op	Msg_type	Msg_text
 test.t2	analyze	status	Engine-independent statistics collected
-test.t2	analyze	Note	Data truncated for column 'avg_frequency' at row 1
-test.t2	analyze	Note	Data truncated for column 'avg_frequency' at row 1
 test.t2	analyze	status	OK
 SELECT * FROM mysql.index_stats ORDER BY index_name, prefix_arity, table_name;
 db_name	table_name	index_name	prefix_arity	avg_frequency

mysql-test/suite/gcol/r/gcol_keys_innodb.result

@@ -696,8 +696,6 @@ Warning	1264	Out of range value for column 'b' at row 1
 SELECT * FROM t WHERE c = '0';
 a	b	c
 1	127	0
-Warnings:
-Warning	1264	Out of range value for column 'b' at row 1
 DROP TABLE t;
 #
 # Bug#21688115 VIRTUAL COLUMN COMPUTATION SAVE_IN_FIELD()

sql/sql_table.cc

@@ -7401,11 +7401,6 @@ static bool mysql_inplace_alter_table(THD *thd,
   bool reopen_tables= false;
   bool res;
 
-  /*
-    Set the truncated column values of thd as warning
-    for alter table.
-  */
-  thd->count_cuted_fields = CHECK_FIELD_WARN;
   DBUG_ENTER("mysql_inplace_alter_table");
 
   /*
@@ -9694,9 +9689,16 @@ bool mysql_alter_table(THD *thd, const LEX_CSTRING *new_db,
     if (use_inplace)
     {
       table->s->frm_image= &frm;
+      enum_check_fields save_count_cuted_fields= thd->count_cuted_fields;
+      /*
+        Set the truncated column values of thd as warning
+        for alter table.
+      */
+      thd->count_cuted_fields = CHECK_FIELD_WARN;
       int res= mysql_inplace_alter_table(thd, table_list, table, altered_table,
                                          &ha_alter_info, inplace_supported,
                                          &target_mdl_request, &alter_ctx);
+      thd->count_cuted_fields= save_count_cuted_fields;
       my_free(const_cast<uchar*>(frm.str));
 
       if (res)