LifeinAsia - 8:01 pm on Mar 14, 2013 (gmt 0)
yes they are both primary key
You mean the indexes on id and serial are BOTH primary keys? Um, I'm surprised this is even possible- it violates the purpose of a *primary* key.
around 5000 rows on each table, so there is bound to be some delay as each entry is being evaluated
This is exactly what DBs are designed to do- comparing 2 5,000-row tables should be a trivial task for any DB. We regularly join tables with millions of rows, generating a result set in seconds at the most.