Re: drop/truncate table sucks for large values of shared buffers

On 2015-07-02 16:08:03 +0300, Heikki Linnakangas wrote:
> I'm marking this as "returned with feedback" in the commitfest. In addition
> to the issues raised so far, ISTM that the patch makes dropping a very large
> table with small shared_buffers slower (DropForkSpecificBuffers() is O(n)
> where n is the size of the relation, while the current method is
> O(shared_buffers))

I think upthread there was talk about only using the O(relsize) approach
if relsize << NBuffers. That's actually a pretty common scenario,
especially in testsuites.

> I concur that we should explore using a radix tree or something else that
> would naturally allow you to find all buffers for relation/database X
> quickly.

I unsurprisingly think that's the right way to go. But I'm not sure if
it's not worth to add another layer of bandaid till were there...

Greetings,

Andres Freund