MDEV-23836: Assertion `! is_set() || m_can_overwrite_status' in

Diagnostics_area::set_error_status (interrupted ALTER TABLE under LOCK)

Analysis: KILL_QUERY is not ignored when local memory used exceeds maximum
session memory. Hence the query proceeds, OK is sent and we end up
reopening tables that are marked for reopen. During this, kill status is
eventually checked and assertion failure happens during trying to send error
message because OK has already been sent.
Fix: Ok is already sent so statement has already executed. It is too
late to give error. So ignore kill.

mysql-test/main/alter_table.result

@@ -3415,5 +3415,23 @@ ERROR 0A000: ALGORITHM=INPLACE is not supported for this operation. Try ALGORITH
 delete from t1 where a = 11;
 drop table t1;
 #
+# MDEV-23836: Assertion `! is_set() || m_can_overwrite_status' in
+# Diagnostics_area::set_error_status (interrupted ALTER TABLE under LOCK)
+#
+SET @max_session_mem_used_save= @@max_session_mem_used;
+CREATE TABLE t1 (a INT);
+SELECT * FROM t1;
+a
+ALTER TABLE x MODIFY xx INT;
+ERROR 42S02: Table 'test.x' doesn't exist
+SET SESSION max_session_mem_used= 8192;
+LOCK TABLE t1 WRITE;
+ALTER TABLE t1 CHANGE COLUMN IF EXISTS b c INT;
+Warnings:
+Note	1054	Unknown column 'b' in 't1'
+SET SESSION max_session_mem_used = @max_session_mem_used_save;
+UNLOCK TABLES;
+DROP TABLE t1;
+#
 # End of 10.5 tests
 #

mysql-test/main/alter_table.test

@@ -2661,6 +2661,28 @@ delete from t1 where a = 11;
 # cleanup
 drop table t1;
 
+--echo #
+--echo # MDEV-23836: Assertion `! is_set() || m_can_overwrite_status' in
+--echo # Diagnostics_area::set_error_status (interrupted ALTER TABLE under LOCK)
+--echo #
+
+SET @max_session_mem_used_save= @@max_session_mem_used;
+
+CREATE TABLE t1 (a INT);
+SELECT * FROM t1;
+
+--error ER_NO_SUCH_TABLE
+ALTER TABLE x MODIFY xx INT;
+
+SET SESSION max_session_mem_used= 8192;
+LOCK TABLE t1 WRITE;
+
+ALTER TABLE t1 CHANGE COLUMN IF EXISTS b c INT;
+
+SET SESSION max_session_mem_used = @max_session_mem_used_save;
+UNLOCK TABLES;
+DROP TABLE t1;
+
 --echo #
 --echo # End of 10.5 tests
 --echo #

sql/lock.cc

@@ -356,7 +356,7 @@ bool mysql_lock_tables(THD *thd, MYSQL_LOCK *sql_lock, uint flags)
 end:
   THD_STAGE_INFO(thd, org_stage);
 
-  if (thd->killed)
+  if (thd->killed && !thd->get_stmt_da()->is_ok())
   {
     thd->send_kill_message();
     if (!rc)

sql/sql_base.cc

@@ -2609,7 +2609,9 @@ void Locked_tables_list::mark_table_for_reopen(THD *thd, TABLE *table)
 bool
 Locked_tables_list::reopen_tables(THD *thd, bool need_reopen)
 {
-  Open_table_context ot_ctx(thd, MYSQL_OPEN_REOPEN);
+  bool is_ok= thd->get_stmt_da()->is_ok();
+  Open_table_context ot_ctx(thd, !is_ok ? MYSQL_OPEN_REOPEN:
+                                  MYSQL_OPEN_IGNORE_KILLED | MYSQL_OPEN_REOPEN);
   uint reopen_count= 0;
   MYSQL_LOCK *lock;
   MYSQL_LOCK *merged_lock;