Carlos H. Reimer wrote: > Hi, > > I would like to use Slony-I to replicate our database but some tables don´t > have primary keys defined. One alternative is to let Slony-I define it for > me but in this case some applications could be affected, right? > > Yes, a couple of problems can arise:
1. There is a new failure mode that no longer existed; applications could insert values to the table and encounter failures due to non-uniqueness of the new column. That shouldn't happen if you're not messing with the sequence that is used, but it's a potential problem. 2. SELECT * from some_table; ...now has an additional column with a pretty funky name. Potentially, the new column might not forcibly be "at the end", where apps might be prone to ignore it... > Depending how the SQL statements are used we could have more or less work, > or am I wrong? I'm not sure what you mean by "more or less work." - The added column means that the table gets a little bigger. - The added index consumes some resources, both disk space and general resource consumption. - If the table is large, it will take some time to alter the table to add the new column, populate it, and then index it. That could be an undesirable outage... _______________________________________________ Slony1-general mailing list [email protected] http://gborg.postgresql.org/mailman/listinfo/slony1-general
