Re: Visibility map, partial vacuums

Simon Riggs <simon@2ndQuadrant.com> writes:
> On Mon, 2008-10-27 at 14:03 +0200, Heikki Linnakangas wrote:
>> Lazy VACUUM only needs to visit pages that are '0' in the visibility 
>> map. This allows partial vacuums, where we only need to scan those parts 
>> of the table that need vacuuming, plus all indexes.

> Just realised that this means we still have to visit each block of a
> btree index with a cleanup lock.

Yes, and your proposal cannot fix that.  Read "The Deletion Algorithm"
in nbtree/README, particularly the second paragraph.
        regards, tom lane