unable_to_parse_set_statement(): [WARNING] Unable to parse unknown

[Habeeb556]

Issue Description

After upgrading from ProxySQL 2.1.0 to 2.7.1, query parsing has changed significantly. ProxySQL fails to parse certain SQL statements, such as dynamic SET SESSION sql_mode queries, and logs a warning instead of forwarding the query to MySQL. This impacts debugging compared to 2.1.0, where backend errors were logged transparently.

Log in 2.7.1:

MySQL_Session.cpp:8414:unable_to_parse_set_statement(): [WARNING] Unable to parse unknown SET query from client 127.0.0.1:51168. Setting lock_hostgroup. Please report a bug for future enhancements:SET SESSION sql_mode =
                                        REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(
                                        @@sql_mode,
                                        "STRICT_ALL_TABLES,", ""),
                                        ",STRICT_ALL_TABLES", ""),
                                        "STRICT_ALL_TABLES", ""),
                                        "STRICT_TRANS_TABLES,", ""),
                                        ",STRICT_TRANS_TABLES", ""),
                                        "STRICT_TRANS_TABLES", "")

Log in 2.1.0:

MySQL_Session.cpp:4014:handler_minus1_LogErrorDuringQuery(): [WARNING] Error during query on (1,mysql-01,3306,36833): 1048, Column 'id' cannot be null

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ProxySQL Version

• Affected: 2.7.1
• Previous: 2.1.0

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Steps to Reproduce

1. Configure ProxySQL 2.7.1 to connect to MySQL.
2. Run the above query via ProxySQL.
3. Observe the log warning instead of backend execution.

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Expected Behavior

ProxySQL should forward valid SQL queries to MySQL or provide actionable error messages.

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Impact

Query parsing limitations in 2.7.1 disrupt applications relying on dynamic SQL and make debugging more complex compared to 2.1.0.

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Proposed Solution

1. Allow complex SQL queries to pass to MySQL unaltered.
2. Provide configuration options to relax query parsing.
3. Update documentation to clarify parsing behavior.

Thank you for reviewing this report!

[Habeeb556]

I think this is related to #3317. Could you help me with this @JavierJF?