On Fri, Apr 25, 2025 at 4:42 AM Amit Kapila <amit.kapil...@gmail.com> wrote: > > On Fri, Apr 25, 2025 at 10:46 AM Masahiko Sawada <sawada.m...@gmail.com> > wrote: > > > > What I'm concerned about is the back branches. With this approach all > > back branches will have such degradations and it doesn't make sense to > > me to optimize SnapBuildCommitTxn() codes in back branches. > > > > One possibility could be that instead of maintaining an entire > snapshot in fast_forward mode, we can maintain snapshot's xmin in each > ReorderBufferTXN. But then also, how would we get the minimum > txns_by_base_snapshot_lsn as we are getting now in > ReorderBufferGetOldestXmin? I think we need to traverse the entire > list of txns to get it in fast_forward mode but that may not show up > because it will not be done for each transaction. We can try such a > thing, but it won't be clean to have fast_forward specific code and > also it would be better to add such things only for HEAD.
Agreed. > Can you think of any better ideas? No idea. Hmm, there seems no reasonable way to fix this issue for back branches. I consented to the view that these costs were something that we should have paid from the beginning. Regards, -- Masahiko Sawada Amazon Web Services: https://aws.amazon.com
