Re: 5 minutes to pg_dump nothing

"Nikita The Spider The Spider" <nikitathespider@gmail.com> writes:
> I think I found the problem. getTypes() calls findFuncByOid() twice
> for each item it sees. A comment at the top of findFuncByOid() says,
> "should hash this, but just do linear search for now". So that funtion
> is O(n)/2 where n = the # of functions found by the query in
> getFuncs(), and since it's called twice for each item in getTypes, the
> overall performance is O(m * n) where n = # of functions and m = # of
> types. As I said before, I have ~56000 items in pg_type and the query
> at the top of getFuncs returns ~98000 rows so for me performance is
> O(5.4 billion)-ish.

Hah, so you need *both* a lot of types and a lot of functions to have
a problem.

> Thanks for your help! Given that this problem seems to be triggered by
> a sort of edge case and the fix is non-trivial, I guess I should not
> expect a new version of pg_dump soon?

We might look into fixing it for 8.3, but I doubt we'd risk back-patching
such a change to older branches.

            regards, tom lane