On 2017-02-03 19:13:45 -0600, Jim Nasby wrote:
> No, I noticed it while reading code. Removing that does mean that if any
> non-default strategy (in any backend) hits that buffer again then the buffer
> will almost certainly migrate into the main buffer pool the next time one of
> the rings hits that buffer

Well, as long as the buffer is used from the ring, BufferAlloc() -
BufferAlloc() will reset the usagecount when rechristening the
buffer. So unless anything happens inbetween the buffer being remapped
last and remapped next, it'll be reused. Right?

The only case where I can see the old logic mattering positively is for
synchronized seqscans.  For pretty much else that logic seems worse,
because it essentially prevents any buffers ever staying in s_b when
only ringbuffer accesses are performed.

I'm tempted to put the old logic back, but more because this likely was
unintentional, not because I think it's clearly better.

> Also, shouldn't there be warnings or something from having a function
> argument that's never used?

No, that's actually fairly common in our codebase.

- Andres

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