On 2/3/19, 1:48 PM, "Masahiko Sawada" <sawada.m...@gmail.com> wrote: > On Sat, Feb 2, 2019 at 7:00 PM Alvaro Herrera <alvhe...@2ndquadrant.com> > wrote: >> >> On 2019-Feb-01, Bossart, Nathan wrote: >> >> > IMHO we could document this feature at a slightly higher level without >> > leaving out any really important user-facing behavior. Here's a quick >> > attempt to show what I am thinking: >> > >> > With this option, VACUUM skips all index cleanup behavior and >> > only marks tuples as "dead" without reclaiming the storage. >> > While this can help reclaim transaction IDs faster to avoid >> > transaction ID wraparound (see Section 24.1.5), it will not >> > reduce bloat. >> >> Hmm ... don't we compact out the storage for dead tuples? If we do (and >> I think we should) then this wording is not entirely correct. > > Yeah, we remove tuple and leave the dead ItemId. So we actually > reclaim the almost tuple storage.
Ah, yes. I was wrong here. Thank you for clarifying. > Attached the updated patch and the patch for vacuumdb. Thanks! I am hoping to take a deeper look at this patch in the next couple of days. Nathan
