| Bug #71641 | table_setup_actors::update_row_values function is unnecessary. | ||
|---|---|---|---|
| Submitted: | 9 Feb 2014 23:49 | Modified: | 1 Oct 2014 13:34 |
| Reporter: | 徹 赤松 | Email Updates: | |
| Status: | Not a Bug | Impact on me: | |
| Category: | MySQL Server: Performance Schema | Severity: | S5 (Performance) |
| Version: | 5.7.3, 5.7.4 | OS: | Linux |
| Assigned to: | Marc ALFF | CPU Architecture: | Any |
| Tags: | performance_schema, table_setup_actors.cc, update_row_values | ||
[26 Jun 2014 13:36]
MySQL Verification Team
Hello!
Thank you for the report.
IMHO table_setup_actors::update_row_values function is kept in for futuristic requirements.
int table_setup_actors::update_row_values(TABLE *table,
const unsigned char *old_buf,
unsigned char *new_buf,
Field **fields)
{
Field *f;
for (; (f= *fields) ; fields++)
{
if (bitmap_is_set(table->write_set, f->field_index))
{
switch(f->field_index)
{
case 0: /* HOST */
case 1: /* USER */
case 2: /* ROLE */
return HA_ERR_WRONG_COMMAND; <---- this is what it returns currently
break;
default:
DBUG_ASSERT(false);
}
}
}
return 0;
}
Looking at the below case, it seems only DELETE/INSERT's are allowed against setup_actors.
mysql>
mysql> select * from performance_schema.setup_actors;
+------+------+------+
| HOST | USER | ROLE |
+------+------+------+
| % | % | % |
+------+------+------+
1 row in set (0.00 sec)
mysql> update performance_schema.setup_actors set HOST='localhost';
ERROR 1683 (HY000): Invalid performance_schema usage.
mysql>
mysql> DELETE FROM performance_schema.setup_actors;
Query OK, 1 row affected (0.00 sec)
mysql> INSERT INTO performance_schema.setup_actors (HOST,USER,ROLE) VALUES('localhost','joe','%');
Query OK, 1 row affected (0.00 sec)
mysql> INSERT INTO performance_schema.setup_actors (HOST,USER,ROLE) VALUES('%','sam','%');
Query OK, 1 row affected (0.00 sec)
mysql> select * from performance_schema.setup_actors;
+-----------+------+------+
| HOST | USER | ROLE |
+-----------+------+------+
| localhost | joe | % |
| % | sam | % |
+-----------+------+------+
2 rows in set (0.00 sec)
[26 Jun 2014 13:37]
MySQL Verification Team
Also, see the doc request for this Bug #71956
[1 Oct 2014 13:34]
Marc ALFF
The method table_setup_actors::update_row_values() has indeed only one possible outcome, which is return HA_ERR_WRONG_COMMAND. This function *is* necessary, because ha_perfschema::update_row() need to execute something (assumption is that m_table->update_row is not NULL), and even when preventing UPDATE with more restrictive security permissions, this method can still be executed when users are not supposed to update tables, for example when --skip-grants is used, so an implementation is required. I agree that table_setup_actors::update_row_values() could be simplified to 1 line, but this is not a functional bug by itself. It is hardly a performance bug either, since this is an error path already. This bug is about a possible code cleanup that has otherwise no impact. For GA releases (up to 5.6), this is not desirable to change. For the current release (5.7), table_setup_actors::update_row_values() in the current form is reserved for future use, so changing the code structure is not desirable a this point. Thank you for the report and your attention to details. While this specific bug report is closed with no code change, I would like to emphasis that bug reports of this nature are welcome.
Description: There are table_setup_actors::update_row_values function in mysqld version 5.7.3 storage/perfschema/table_setup_actors.cc. 239 int table_setup_actors::update_row_values(TABLE *table, 240 const unsigned char *old_buf, 241 unsigned char *new_buf, 242 Field **fields) 243 { 244 Field *f; 245 246 for (; (f= *fields) ; fields++) 247 { 248 if (bitmap_is_set(table->write_set, f->field_index)) 249 { 250 switch(f->field_index) 251 { 252 case 0: /* HOST */ 253 case 1: /* USER */ 254 case 2: /* ROLE */ 255 return HA_ERR_WRONG_COMMAND; 256 break; 257 default: 258 DBUG_ASSERT(false); 259 } 260 } 261 } 262 263 return 0; 264 } All fields cannot update, so is this function unnecessary? If update_row_values function in unnecessary, function fefinition in storage/perfschema/table_setup_actors.h is not necessary. 72 virtual int update_row_values(TABLE *table, 73 const unsigned char *old_buf, 74 unsigned char *new_buf, 75 Field **fields); I am pleased if a reply is got. How to repeat: mysql> select * from performance_schema.setup_actors; +------+------+------+ | HOST | USER | ROLE | +------+------+------+ | % | % | % | +------+------+------+ 1 row in set (0.00 sec) mysql> update performance_schema.setup_actors set HOST='localhost' where USER='%'; ERROR 1683 (HY000): Invalid performance_schema usage. mysql> update performance_schema.setup_actors set USER='root' where HOST='%'; ERROR 1683 (HY000): Invalid performance_schema usage.