2008/6/28 Tom Lane <[EMAIL PROTECTED]>: > "Bob Duffey" <[EMAIL PROTECTED]> writes: > > I'm seeing some query plans that I'm not expecting. The table in > question > > is reasonably big (130,000,000 rows). The table has a primary key, > indexed > > by one field ("ID", of type bigint). Thus, I would expect the following > > query to simply scan through the table using the primary key: > > > select * from "T" order by "ID" > > This is not wrong, or at least not obviously wrong. A full-table > indexscan is often slower than seqscan-and-sort. If the particular > case is wrong for you, you need to look at adjusting the planner's > cost parameters to match your environment. But you didn't provide any > evidence that the chosen plan is actually worse than the alternative ... >
Hi Tom, Thanks for the reply. Is there some way I can provide evidence of the alternative being slower/faster? I guess that's my intuition, but since I can't figure out how to get postgres to use the alternative as the query plan, I can't test if it's slower! Bob