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MDEV-24411: Trigger doesn't work correctly with bulk insert

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Executing an INSERT statement in PS mode having positional parameter
bound with an array could result in incorrect number of inserted rows
in case there is a BEFORE INSERT trigger that executes yet another
INSERT statement to put a copy of row being inserted into some table.

The reason for incorrect number of inserted rows is that a data structure
used for binding positional argument with its actual values is stored
in THD (this is thd->bulk_param) and reused on processing every INSERT
statement. It leads to consuming actual values bound with top-level
INSERT statement by other INSERT statements used by triggers' body.

To fix the issue, reset the thd->bulk_param temporary to the value nullptr
before invoking triggers and restore its value on finishing its execution.
This commit is contained in:
Dmitry Shulga
2024-06-24 21:51:19 +07:00
parent d513a4ce74
commit 8b169949d6
2 changed files with 121 additions and 0 deletions
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21
sql/sql_insert.cc
View File

@ -1021,10 +1021,19 @@ bool mysql_insert(THD *thd, TABLE_LIST *table_list,
*/
restore_record(table,s->default_values); // Get empty record
table->reset_default_fields();
/*
Reset the sentinel thd->bulk_param in order not to consume the next
values of a bound array in case one of statement executed by
the trigger's body is INSERT statement.
*/
void *save_bulk_param= thd->bulk_param;
thd->bulk_param= nullptr;
if (unlikely(fill_record_n_invoke_before_triggers(thd, table, fields,
*values, 0,
TRG_EVENT_INSERT)))
{
thd->bulk_param= save_bulk_param;
if (values_list.elements != 1 && ! thd->is_error())
{
info.records++;
@ -1038,6 +1047,7 @@ bool mysql_insert(THD *thd, TABLE_LIST *table_list,
error=1;
break;
}
thd->bulk_param= save_bulk_param;
}
else
{
@ -1067,12 +1077,22 @@ bool mysql_insert(THD *thd, TABLE_LIST *table_list,
}
}
table->reset_default_fields();
/*
Reset the sentinel thd->bulk_param in order not to consume the next
values of a bound array in case one of statement executed by
the trigger's body is INSERT statement.
*/
void *save_bulk_param= thd->bulk_param;
thd->bulk_param= nullptr;
if (unlikely(fill_record_n_invoke_before_triggers(thd, table,
table->
field_to_fill(),
*values, 0,
TRG_EVENT_INSERT)))
{
thd->bulk_param= save_bulk_param;
if (values_list.elements != 1 && ! thd->is_error())
{
info.records++;
@ -1081,6 +1101,7 @@ bool mysql_insert(THD *thd, TABLE_LIST *table_list,
error=1;
break;
}
thd->bulk_param= save_bulk_param;
}
/*

100
tests/mysql_client_test.c
View File

@ -21870,6 +21870,103 @@ static void test_mdev19838()
rc = mysql_query(mysql, "drop table mdev19838");
myquery(rc);
}
static void test_mdev_24411()
{
int rc;
MYSQL_STMT *stmt;
MYSQL_BIND bind;
MYSQL_RES *result;
MYSQL_ROW row;
my_ulonglong row_count;
unsigned int vals[] = { 1, 2, 3};
unsigned int vals_array_len = 3;
const char *insert_stmt= "INSERT INTO t1 VALUES (?)";
myheader("test_mdev_24411");
rc= mysql_query(mysql, "DROP TABLE IF EXISTS t1");
myquery(rc);
rc= mysql_query(mysql, "DROP TABLE IF EXISTS t2");
myquery(rc);
rc= mysql_query(mysql, "CREATE TABLE t1 (a INT)");
myquery(rc);
rc= mysql_query(mysql, "CREATE TABLE t2 (a INT)");
myquery(rc);
rc= mysql_query(mysql,
"CREATE TRIGGER t1_bi BEFORE INSERT ON t1 FOR EACH ROW "
"BEGIN INSERT INTO t2 (a) VALUES (NEW.a); END;");
myquery(rc);
stmt= mysql_stmt_init(mysql);
check_stmt(stmt);
rc= mysql_stmt_prepare(stmt, insert_stmt, strlen(insert_stmt));
check_execute(stmt, rc);
memset(&bind, 0, sizeof(bind));
bind.buffer_type= MYSQL_TYPE_LONG;
bind.buffer= vals;
rc= mysql_stmt_attr_set(stmt, STMT_ATTR_ARRAY_SIZE, &vals_array_len);
check_execute(stmt, rc);
rc= mysql_stmt_bind_param(stmt, &bind);
check_execute(stmt, rc);
rc= mysql_stmt_execute(stmt);
check_execute(stmt, rc);
/*
It's expected that the INSERT statement adds three rows into
the table t1
*/
row_count = mysql_stmt_affected_rows(stmt);
DIE_UNLESS(row_count == 3);
/*
* Check that the BEFORE INSERT trigger of the table t1 does work correct
* and inserted the rows (1), (2), (3) into the table t2.
*/
rc= mysql_query(mysql, "SELECT 't1' tname, a FROM t1 "
"UNION SELECT 't2' tname, a FROM t2 ORDER BY tname,a");
myquery(rc);
result= mysql_store_result(mysql);
row = mysql_fetch_row(result);
DIE_UNLESS(strcmp(row[0], "t1") == 0 && atoi(row[1]) == 1);
row = mysql_fetch_row(result);
DIE_UNLESS(strcmp(row[0], "t1") == 0 && atoi(row[1]) == 2);
row = mysql_fetch_row(result);
DIE_UNLESS(strcmp(row[0], "t1") == 0 && atoi(row[1]) == 3);
row = mysql_fetch_row(result);
DIE_UNLESS(strcmp(row[0], "t2") == 0 && atoi(row[1]) == 1);
row = mysql_fetch_row(result);
DIE_UNLESS(strcmp(row[0], "t2") == 0 && atoi(row[1]) == 2);
row = mysql_fetch_row(result);
DIE_UNLESS(strcmp(row[0], "t2") == 0 && atoi(row[1]) == 3);
row= mysql_fetch_row(result);
DIE_UNLESS(row == NULL);
mysql_free_result(result);
mysql_stmt_close(stmt);
rc= mysql_query(mysql, "DROP TABLE t1, t2");
myquery(rc);
}
#endif // EMBEDDED_LIBRARY
@ -22307,6 +22404,9 @@ static struct my_tests_st my_tests[]= {
{ "test_mdev20261", test_mdev20261 },
{ "test_mdev_30159", test_mdev_30159 },
{ "test_connect_autocommit", test_connect_autocommit},
#ifndef EMBEDDED_LIBRARY
{ "test_mdev_24411", test_mdev_24411},
#endif
{ 0, 0 }
};