On 3/10/07, Tom Lane <[EMAIL PROTECTED]> wrote:
Also, we know this case works because it already is working: in the situation where VACUUM happens to visit and remove the DEAD tuple(s) before reaching the RECENTLY_DEAD tuples that link forward to them, it treats the RECENTLY_DEAD tuples as a disconnected chain and moves them as-is. I saw tons of this in the traces I was making today, and it doesn't seem to create any bad effects. (My attention was drawn to it because I saw move_chain_tuple being used to move single-member chains, which looks impossible when you first look at the code --- the is-it-a-chain test seems to ensure that we can link either forward or backward. But not so if t_ctid points to an already-removed tuple.)
Oh. So thats the corner case which I missed. This would probably explain how we could miss marking an offset free and thus not remove the corresponding index entry. Thanks, Pavan -- EnterpriseDB http://www.enterprisedb.com
