Re: performance regression in 9.2 when loading lots of small tables

On Tue, Jun 19, 2012 at 10:56 PM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:
> But in the 9.2 branch, the slow phenotype was re-introduced in
> 1575fbcb795fc331f4, although perhaps the details of who is locking
> what differs.  I haven't yet sorted that out.

It very much does. That commit prevents people from creating a
relation in - or renaming a relation into - a schema that is being
concurrently dropped, which in previous releases would have resulted
in inconsistent catalog contents. I admit that it harms your test
case, but how likely is it that someone is going to put every single
table into its own schema? And have shared_buffers low enough for
this to be the dominant cost? I think in real-world scenarios this
isn't going to be a problem - although, of course, making the lock
manager faster would be nifty if we can do it, and this might be a
good test case.

--
Robert Haas
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