GeoffMontee Default value for log_warnings is 2 so this could have too big effect on normal cluster. Can I use value >2 instead ?

Hi jplindst.

In my opinion, not having a PK on a table does deserve a warning by default with Galera, so I think it makes the most sense to log a warning when log_warnings=2.

Are you concerned that the log could be flooded with the message? If so, then you could probably avoid flooding the log by doing a check similar to the check for ER_BINLOG_UNSAFE_STATEMENT. e.g.:

/**

  Auxiliary function to check if the warning for unsafe repliction statements

  should be thrown or suppressed.

  Logic is:

  - If we get more than LIMIT_UNSAFE_WARNING_ACTIVATION_THRESHOLD_COUNT errors

    of one type, that type of errors will be suppressed for

    LIMIT_UNSAFE_WARNING_ACTIVATION_TIMEOUT.

  - When the time limit has been reached, all suppression is reset.

  This means that if one gets many different types of errors, some of them

  may be reset less than LIMIT_UNSAFE_WARNING_ACTIVATION_TIMEOUT. However at

  least one error is disable for this time.

  SYNOPSIS:

  @params

   unsafe_type - The type of unsafety.

  RETURN:

    0   0k to log

    1   Message suppressed

*/

static bool protect_against_unsafe_warning_flood(int unsafe_type)

https://github.com/MariaDB/server/blob/mariadb-10.5.8/sql/sql_class.cc#L7170

GeoffMontee Thanks for the feedback. I have another question. Should I print warning to error log only or should every DML that causes unsafe Galera operation also print warning? At the moment it seems based on mtr-tests we have: Completed: Failed 181/1243 tests, 85.44% were successful. I should somehow modify that many tests using current implementation and above will not help on that. Here is example of current output:

 INSERT INTO t2 VALUES ('abc');

+Warnings:

+Warning	1105	wsrep_certify_nonPK is enabled, so Galera certified DML command on a table (test.t2) without an explicit primary key. For optimal performance and consistency, it is recommended to define a primary key for all tables that Galera writes to.

Hi jplindst,

Should I print warning to error log only or should every DML that causes unsafe Galera operation also print warning?

Good point. It would probably make sense to log a warning for all unsafe operations. I believe that some other unsafe operations might be:

• A session has binlog_format set to STATEMENT, and the session writes to an InnoDB table. The associated statement will be logged in statement-based format, which is unsupported by Galera,
• A session has binlog_format set to MIXED, and the session writes to an InnoDB table. The associated statement could be logged in statement-based format, which is unsupported by Galera.
• A node has wsrep_replicate_myisam set to OFF, and a session on the node writes to a MyISAM table, so the write will not be replicated.
• A node has wsrep_replicate_aria set to OFF, and a session on the node writes to an Aria table, so the write will not be replicated.
• A session writes to any other non-InnoDB storage engine , so the write will not be replicated.
• A session has wsrep_on set to OFF, and the session writes to an InnoDB table, so the write will not be replicated.

What do you think about those?

Thanks!

GeoffMontee In this ticket I will handle only primary key issue. Rest of the ideas will be considered on MDEV-20008.

https://github.com/MariaDB/server/commit/22fe31fec7648ac340690aefbab6053bbf5d02f6