Re: sequence scan problem

John Beaver <john(dot)e(dot)beaver(at)gmail(dot)com> writes:
> Can anyone explain this? There should only ever be a maximum of about 50
> rows returned when the query is executed.

Is the estimate that 197899 rows of gene_prediction_view have
go_term_ref = 2 about right? If not, then we need to talk about
fixing your statistics. If it is in the right ballpark then I do
not see *any* plan for this query that runs in small time.
The only way to avoid a seqscan on functional_linkage_scores would
be to do 198K^2 index probes into it, one for each combination of
matching fs1 and fs2 rows; I can guarantee you that that's not a win.

The fact that the planner is estimating 352770803726 result rows
compared to your estimate of 50 offers some hope that it's a stats
problem, but ...

regards, tom lane