maria-discuss team mailing list archive

["Mark Wadham" <ubuntu@xxxxxx>]

On 21 Jul 2016, at 9:05, Mark Wadham wrote:
> I don't think this was the case during our testing, but I'll test it 
> again anyway.  If I understand RSU mode correctly all it does is 
> ensure that DDL statements aren't replicated to the other nodes.  
> AFAIK it won't stop the write events from the other nodes from being 
> synced to the node in RSU mode, meaning that if we have writes to the 
> table being altered we could run into problems.  We have some very 
> large tables and one of them we tested took around 7h 45min to add a 
> column.

Confirmed this, on node 0:

SET GLOBAL wsrep_OSU_method='RSU';

show status like 'wsrep%';

- still shows "Synced"

If we then alter table on node 0 and try to insert to the same table on 
node 1 we get a deadlock error.

Mark