Bug #2083 EE_ error codes (EE_DELETE, EE_WRITE) end up in the binlog, making slave stop
Submitted: 10 Dec 2003 12:53 Modified: 30 Jan 2004 6:07
Reporter: Guilhem Bichot Email Updates:
Status: Closed Impact on me:
Category:MySQL Server: Replication Severity:S3 (Non-critical)
Version:4.0 OS:Any (all)
Assigned to: Guilhem Bichot

[10 Dec 2003 12:53] Guilhem Bichot
Sometimes, a query can succeed on master, but still an error code (a EE_ error code, not a ER_ error code) is written in the binary log for this query.
manually delete t.MYI
Server will say "ok" to client (no error) but as my_delete("t.MYI") failed with error code EE_DELETE (failure which is not critical as the MYI did not exist and our goal was to remove it), thd->net.last_error is EE_DELETE (6). So the query gets logged (in the binlog) with error code 6.
To sum up: client got no error, but error is written in binlog.
So if the query runs fine on slave (my_delete() succeeds), slave will say: "got error 0 (no error), expected error 6 (invalid error code)".
The example of the customer is:
mysqld got a "disk full" on master when writing a MyISAM table; mysqld retried the write and succeeded, so no error was reported to client. But still thd->net.last_error was left to EE_WRITE, which was written to binlog, and slave stopped. (True, the "disk full" was logged in the master's .err file.)

How to repeat:
On master:
manually delete t.MYI
see slave stop with error

Suggested fix:
As EE_ errors in binlog can probably be considered neglectable (because if master logged no ER_ error in binlog it means that it considers the query successful), there are 2 ways:
1) master should write thd->net.last_error to binlog only if it's a ER_
2) slave should ignore error read in binlog if it's not a ER_.
Advantages of 2):
* to remove the bug, users just need to upgrade their slave, which is usually easier than upgrading the master.
* EE_ codes are in the binlog, they can be used for debugging
Advantage of 1):
more logical (don't write an error code if you consider the query successful).

I vote for 2) and will propose a patch in this sense.
[30 Jan 2004 6:07] Guilhem Bichot
Thank you for your bug report. This issue has been committed to our
source repository of that product and will be incorporated into the
next release.

If necessary, you can access the source repository and build the latest
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Additional info:

Fixed in ChangeSet@1.1622.2.1, 2003-12-16 11:10:50+01:00, guilhem@mysql.com