| Bug #99857 | mysql_use_result() can't get result if slave no set slave_uuid | ||
|---|---|---|---|
| Submitted: | 12 Jun 2020 3:32 | Modified: | 20 Aug 2020 1:05 |
| Reporter: | su fei | Email Updates: | |
| Status: | Verified | Impact on me: | |
| Category: | MySQL Server: Command-line Clients | Severity: | S1 (Critical) |
| Version: | 5.7.31，8.0.20 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
| Tags: | mysql_use_result | ||
[17 Jun 2020 10:58]
MySQL Verification Team
Hi, How did you get 8.0.20 to start without server_uuid ?
[17 Jun 2020 14:06]
su fei
I just use MySQL replication protocol library like go-mysql as a MySQL slave to sync binlog from master. It's very terrible that other session get Unknown MySQL error due to an replication protocol client connection without slave_uuid.
[19 Jun 2020 11:01]
MySQL Verification Team
Hi, I think the mysql bug here would be on the side of the client app that did not set UUID, but mysql should work same with regards to this with and without --quick so I'm verifying this bug. Thanks for the report Bogdan
[20 Aug 2020 1:05]
su fei
I find that old versions(such as mysql 5.7.21) have not this problem.
the resean:
In version 5.7.31, the function read_one_row() is :
// check field length
len = (ulong)net_field_length_checked(&pos, (ulong)(end_pos - pos));
if (pos > end_pos) {
set_mysql_error(mysql, CR_UNKNOWN_ERROR, unknown_sqlstate);
return -1;
}
if (len == NULL_LENGTH) { /* null field */
row[field] = 0;
*lengths++ = 0;
} else {
row[field] = (char *)pos;
pos += len;
*lengths++ = len;
}
First, should check whether the field is null,like version 5.7.21;
if the last field value is null, in version 5.7.31 , Unknown MySQL error will happen
[5 Aug 2021 10:16]
MySQL Verification Team
Bug #104544 marked as duplicate of this one
Description: I get a Unknown MySQL error If a slave connect master without user variable of slave_uuid , I can,t use mysql_use_result() to get result of sql 'show slave hosts;' How to repeat: Using replication protocol to connect MySQL server, the process have not set user variable of slave_uuid. Using MySQL client without --quick option connect server,run: mysql> show slave hosts\G *************************** 1. row *************************** Server_id: 2019314 Host: db1n9 Port: 8018 Master_id: 9080 Slave_UUID: 1 row in set (0.00 sec) When with --quick option connect server,run: mysql> show slave hosts\G ERROR 2000 (HY000): Unknown MySQL error 0 rows in set (0.00 sec) Unfortunately, the result is Unknown MySQL error