AWS MySQL 5.7 support broken due to Unknown system variable 'transaction_isolation'

[dnovitski]

Hi,

In https://github.com/github/gh-ost/blob/master/go/mysql/connection.go#L130 support was added for transaction_isolation, however this does not exist in some older MySQL 5.7 versions.

For these MySQL, gh-ost fails with:

2023-10-09 17:10:17 FATAL Error 1193: Unknown system variable 'transaction_isolation' 

Example Aurora MySQL RDS system where this fails:

MySQL> SHOW VARIABLES LIKE '%isolation%';
+---------------+-----------------+
| Variable_name | Value           |
+---------------+-----------------+
| tx_isolation  | REPEATABLE-READ |
+---------------+-----------------+

MySQL> SHOW VARIABLES LIKE '%version%';
+-------------------------+------------------------------+
| Variable_name           | Value                        |
+-------------------------+------------------------------+
| aurora_version          | 2.11.1                       |
| innodb_version          | 5.7.12                       |
| protocol_version        | 10                           |
| slave_type_conversions  |                              |
| tls_version             | TLSv1,TLSv1.1,TLSv1.2        |
| version                 | 5.7.12-log                   |
| version_comment         | MySQL Community Server (GPL) |
| version_compile_machine | x86_64                       |
| version_compile_os      | Linux                        |
+-------------------------+------------------------------+

Can the transaction_isolation parameter be made optional or revert back to tx_isolation incase transaction_isolation does not exist?

[dbadmin-irl]

FYI This is already referenced here #1262
Otherwise try aurora 2.12 or 3.x where the new parameter is supported.

[dnovitski]

Thanks! We are planning to upgrade to 2.12 soon. I'm closing this issue as it's a duplicate for #1262