Re: enforcing a plan (in brief)

pgsql(at)mohawksoft(dot)com writes:
> I think that is sort of arrogant. Look at Oracle, you can give the planner
> hints in the form of comments.

Arrogant or not, that's the general view of the people who work on the
planner.

The real issue is not so much whether the planner will always get things
right --- it won't, and no one imagines that it will ever be perfect.
The real issue is that we have limited manpower, and designing and
implementing a useful hint facility is a nontrivial project. (Not to
mention that maintaining such a thing in the face of frequent,
fundamental changes to the underlying planner and executor capabilities
would be an outright nightmare.)

The people who are actually doing the work think their time is more
usefully spent on improving the planner's intelligence than on devising
ways to override it.

regards, tom lane