Re: Background LRU Writer/free list - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Background LRU Writer/free list
Date
Msg-id 5838.1176918786@sss.pgh.pa.us
Whole thread Raw
In response to Background LRU Writer/free list  (Greg Smith <gsmith@gregsmith.com>)
Responses Re: Background LRU Writer/free list  (Greg Smith <gsmith@gregsmith.com>)
List pgsql-hackers
Greg Smith <gsmith@gregsmith.com> writes:
> With the new patch, the LRU writer is fairly well bounded in that it 
> doesn't write out more than it thinks it will need; you shouldn't get into 
> a situation where many more pages are written than will be used in the 
> near future.  Given that mindset, shouldn't pages the LRU scan writes just 
> get moved onto the free list?

This just seems like a really bad idea: throwing away data we might
want.  Furthermore, if the page was dirty, then it's probably been
accessed more recently than adjacent pages that are clean, so
preferentially zapping just-written pages seems backwards.
        regards, tom lane


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