Re: Dirty pages in freelist cause WAL stuck

On Tue, Dec 19, 2006 at 05:53:06PM +0900, ITAGAKI Takahiro wrote:
> "Simon Riggs" <simon(at)2ndquadrant(dot)com> wrote:
> > Another connected thought is the idea of a having a FullBufferList - the
> > opposite of a free buffer list. When VACUUM/INSERT/COPY fills a block we
> > notify the buffer manager that this block needs writing ahead of other
> > buffers, so that the bgwriter can work more effectively. That seems like
> > it would help with both this current patch and the additional thoughts
> > above.
>
> Do you mean that bgwriter should take care of buffers in freelist, not only
> ones in the tail of LRU? We might need activity control of bgwriter. Buffers
> are reused rapidly in VACUUM or bulk insert, so bgwriter is not sufficient
> if its settings are same as usual.

Actually, if I understand the code, the "LRU" stuff actually only hits
the free list. Also, the only thing that runs the clock sweep (which is
what maintains the LRU-type info) is a backend requesting a page and not
finding one on the free list.
--
Jim Nasby jim(at)nasby(dot)net
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)