On Wed, Sep 23, 2020 at 8:04 AM tsunakawa.ta...@fujitsu.com <tsunakawa.ta...@fujitsu.com> wrote: > > From: Amit Kapila <amit.kapil...@gmail.com> > > > > > Don't > > > > > we need to guarantee the cache to be valid while recovery? > > > > > > > > > > > > > One possibility could be that we somehow detect that the value we > > > > are using is cached one and if so then only do this optimization. > > > > > > I basically like this direction. But I'm not sure the additional > > > parameter for smgrnblocks is acceptable. > > > > > > But on the contrary, it might be a better design that > > > DropRelFileNodeBuffers gives up the optimization when > > > smgrnblocks(,,must_accurate = true) returns InvalidBlockNumber. > > > > > > > I haven't thought about what is the best way to achieve this. Let us see if > > Tsunakawa-San or Kirk-San has other ideas on this? > > I see no need for smgrnblocks() to add an argument as it returns the correct > cached or measured value. >
The idea is that we can't use this optimization if the value is not cached because we can't rely on lseek behavior. See all the discussion between Horiguchi-San and me in the thread above. So, how would you ensure that if we don't use Kirk-San's proposal? -- With Regards, Amit Kapila.
