On Tue, Aug 18, 2020 at 9:44 PM Alvaro Herrera <alvhe...@2ndquadrant.com> wrote: > > On 2020-Aug-17, Ashutosh Sharma wrote: > > > > + if (heap_force_opt == HEAP_FORCE_KILL) > > > + ItemIdSetDead(itemid); > > > > > > I think that if the page is an all-visible page, we should clear an > > > all-visible bit on the visibility map corresponding to the page and > > > PD_ALL_VISIBLE on the page header. Otherwise, index only scan would > > > return the wrong results. > > > > I think we should let VACUUM do that. Please note that this module is > > intended to be used only on a damaged relation and should only be > > operated on damaged tuples of such relations. And the execution of any > > of the functions provided by this module on a damaged relation must be > > followed by VACUUM with DISABLE_PAGE_SKIPPING option on that relation. > > This is necessary to bring back a damaged relation to the sane state > > once a surgery is performed on it. I will try to add this note in the > > documentation for this module. > > It makes sense to recommend VACUUM after fixing the page, but I agree > with Sawada-san that it would be sensible to reset the VM bit while > doing surgery, since that's the state that the page would be in.
Sure, I will try to do that change but I would still recommend to always run VACUUM with DISABLE_PAGE_SKIPPING option on the relation that underwent surgery. We > should certainly *strongly recommend* to do VACUUM DISABLE_PAGE_SKIPPING, > but if users fail to do so, then leaving the VM bit set just means that > we know *for certain* that there will be further corruption as soon as > the XID counter advances sufficiently. > Yeah, I've already added a note for this in the documentation: Note: "After a surgery is performed on a damaged relation using this module, we must run VACUUM with DISABLE_PAGE_SKIPPING option on that relation to bring it back into a sane state." -- With Regards, Ashutosh Sharma EnterpriseDB:http://www.enterprisedb.com
