On Jun 01, Jon Olav Hauglid wrote:
> #At file:///export/home/x/mysql-trunk-bug12585718/ based on
> 3142 Jon Olav Hauglid 2011-06-01
> Bug#12585718 REPLICATION BREAKS WITH LARGE INDEX PREFIX ON UNIQUE INDEX
What was the problem with the replication?
> Tentative patch for discussion purposes.
> Before this patch, creating an index with a prefix longer than the
> maximum supported length only gave a warning for non-unique indexes
> but an error for unique indexes.
> This patch changes the behavior for non-unique indexes so
> an ER_TOO_LONG_KEY error is reported in this case as well.
This was the old MySQL behavior.
Changed later to be a non-fatal error, as an index is only an
optimization aid, and truncating it does not introduce an error.
A unique index, on the other hand, is a constraint. DBMS should not
automatically change it.
But what does it have to do with replication?