On Wed, Jan 20, 2021 at 10:50 AM Andres Freund <and...@anarazel.de> wrote: > > Hi, > > On 2021-01-20 09:24:35 +0530, Amit Kapila wrote: > > I feel extending the deletion mechanism based on the number of LP_DEAD > > items sounds more favorable than giving preference to duplicate > > items. Sure, it will give equally good or better results if there are > > no long-standing open transactions. > > There's a lot of workloads that never set LP_DEAD because all scans are > bitmap index scans. And there's no obvious way to address that. So I > don't think it's wise to purely rely on LP_DEAD. >
Right, I understand this point. The point I was trying to make was that in this new technique we might not be able to delete any tuple (or maybe very few) if there are long-running open transactions in the system and still incur a CPU and I/O cost. I am completely in favor of this technique and patch, so don't get me wrong. As mentioned in my reply to Peter, I am just trying to see if there are more ways we can use this optimization and reduce the chances of regression (if there is any). -- With Regards, Amit Kapila.
