On Tue, May 3, 2016 at 9:47 PM, Kevin Grittner <kgrittn@gmail.com> wrote: > > On Tue, May 3, 2016 at 11:09 AM, Robert Haas <robertmhaas@gmail.com> wrote: > > On Tue, May 3, 2016 at 11:46 AM, Kevin Grittner <kgrittn@gmail.com> wrote: > >>> Uh, I have no idea how this would be fixed if the PageLSN is zero. Do > >>> you? > >> > >> Yes, I see three ways, the most obvious of which is what Amit > >> suggested -- don't do early vacuum on a table which has a hash index. > > > > What do you mean by "early VACUUM"? > > Both vacuuming and hot-pruning adjust xmin based on calling > TransactionIdLimitedForOldSnapshots(TransactionId recentXmin, > Relation relation). I'm talking about having that function, if all > other conditions for the override pass, checking for a hash index, > too. > > > Amit suggested disabling > > HOT-pruning, but HOT-pruning happens completely outside of VACUUM. It > > also happens inside VACUUM, so if we disabled HOT pruning, how could > > we VACUUM at all? Sorry, I am confused. > > I guess we were both talking a bit loosely since (as I mentioned > above) the function that adjusts the xmin is called for a vacuum or > pruning. He mentioned one and I mentioned the other, but it's all > controlled by TransactionIdLimitedForOldSnapshots(). >