"Eric B. Ridge" <ebr@xxxxxxxx> writes: > When is the UPDATE statement inside foo() planned? When the trigger > is first created, or when it's first used per backend, or every time > it's used per backend? First use per backend, ignoring corner cases such as replacing the function definition. > I dunno what plan is being generated, but it's gotta be using a > sequential scan. The issue is probably that the planner is seeing a parameterized query. Try this: prepare foo(int8) as update some_other_table SET field = 'value' WHERE id = $1; explain execute foo(42); and see what plan you get. If the id field has sufficiently discouraging statistics then the planner may think that a seqscan is the safest plan. In a "normal" query where you're comparing id to a constant, the planner can see whether the constant matches any of the most common values for the column --- if it doesn't then an indexscan is a good plan. If you really want a replan every time, you can get it by using EXECUTE. regards, tom lane
