Re: The Order or events TABLE_MAP_EVENT and WRITE_ROW_EVENT

Hello Mansour,

On 6/8/2015 12:05 PM, Mansour Al Akeel wrote:
> In Row based replication setup, I have a trigger on one of the tables
> in a replicated database.
>
> The table "user" has a trigger that inserts values into  "audit".
>
> The sequence of events:
>
> #150608 14:45:18 server id 1  end_log_pos 25066 CRC32 0xb2b66d43
>   Table_map: `drupal`.`users` mapped to number 101
> # at 25066
> #150608 14:45:18 server id 1  end_log_pos 25137 CRC32 0x8a2a06f9
>   Table_map: `drupal`.`audits` mapped to number 70
> # at 25137
> #150608 14:45:18 server id 1  end_log_pos 25211 CRC32 0x0ba847a5
>   Write_rows: table id 101
> # at 25211
> #150608 14:45:18 server id 1  end_log_pos 25315 CRC32 0xbd38092d
>   Write_rows: table id 70 flags: STMT_END_F
> # at 25315
> #150608 14:45:18 server id 1  end_log_pos 25346 CRC32 0x2044e691
>   Xid = 492
> COMMIT/*!*/;
> # at 25346
> #150608 14:46:12 server id 1  end_log_pos 25428 CRC32 0x0e28bf95
>   Query   thread_id=38    exec_time=0     error_code=0
> SET TIMESTAMP=1433760372/*!*/;
> BEGIN
> /*!*/;
> # at 25428
> #150608 14:46:12 server id 1  end_log_pos 25484 CRC32 0x25d127a1
>   Table_map: `drupal`.`users` mapped to number 101
> # at 25484
> #150608 14:46:12 server id 1  end_log_pos 25555 CRC32 0x817735d4
>   Table_map: `drupal`.`audits` mapped to number 70
> # at 25555
> #150608 14:46:12 server id 1  end_log_pos 25629 CRC32 0x18031884
>   Write_rows: table id 101
> # at 25629
> #150608 14:46:12 server id 1  end_log_pos 25733 CRC32 0x50b5823a
>   Write_rows: table id 70 flags: STMT_END_F
> # at 25733
> #150608 14:46:12 server id 1  end_log_pos 25764 CRC32 0xf9855dc6
>   Xid = 500
> COMMIT/*!*/;
> DELIMITER ;
> # End of log file
> ROLLBACK /* added by mysqlbinlog */;
> /*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
> /*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
>
>
>
> As we can see, I am getting:
> TABLE_MAP_EVENT for users
> TABLE_MAP_EVENT  for audits
> WRITE_ROWS for users
> WRITE_ROWS for audits
>
> from https://dev.mysql.com/doc/internals/en/table-map-event.html
>
> "The first event used in Row Based Replication declares how a table
> that is about to be changed is defined. "
>
>
> Based on my understanding, I am expecting:
>
> TABLE_MAP_EVENT for users
> WRITE_ROWS_EVENT for users
> TABLE_MAP_EVENT for audits
> WRITE_ROWS_EVET for audits
>
> I am missing something here ?
>
> Thank you.
>

You are missing the boundaries to your transactions.  Please look again 
closely at the full sequence you quoted

In a transaction, you insert a row into user, which fires a trigger and 
adds a row to audit. That looks like
begin
   table maps for user and audit
   row inserts for user and audit
commit

Then you repeat the sequence for a second row to the user table.

Can you see it now? Those are two sets of rows in two separate 
transactions.

-- 
Shawn Green
MySQL Senior Principal Technical Support Engineer
Oracle USA, Inc. - Hardware and Software, Engineered to Work Together.
Office: Blountville, TN

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