I have a query that has 5 predicates, scanning a table of 400+ million
rows and I have built indexes getting help from design advisor and
other tools. The cost of that query is really low. But I federated the
server and created a nickname for that table, and when I give the same
query against the nickname, it tries to fetch the whole table (cost
1.7 billion), and do the predicate evaluation in my smaller test box.
I did build indices in my test box with 'specification only' clause,
and runstats, and other things. I also read about query pushdown, and
hoping that would help, I changed the cpu_ratio parameter in fed
server's config. Still no joy. Please help.. any links would be
appreciated.
Also, how does one quantify cost of a query..