On Tuesday, December 9, 2025 12:40 AM Vitaly Davydov <[email protected]> wrote: > > On Monday, December 08, 2025 13:24 MSK, "Zhijie Hou (Fujitsu)" > <[email protected]> wrote: > > > On Monday, December 8, 2025 5:47 PM Amit Kapila > <[email protected]> wrote: > > > > > Sawada-san/Vitaly, do you have any opinion on patch or the > > > > > direction to fix? The idea is to get this fixed for HEAD and 18, > > > > > then continue discussion for other bank-branches and the remaining > patches. > > Hi Amit, Zhijie Hou > > Thank you for preparing and comiting 0001 patch. I'm ok with it. I did some > auto testing of the patch and haven't found any problems. As I realized, > another two patches (0002, 0003) are still in review.
Thanks for testing! > > In my previous email I wrote about copy_replication_slot, where restart_lsn is > assigned without any locks, but I'm not sure that email was successfully > delivered. Masahiko Sagawa mentioned about it in one of the latest emails as > well. I also read the answer but not completely understood it at the moment, > sorry (need some more time to investigate). Anyway, I would prefer to use > locks in create_physical_replication_slot rather than rely on signals handling > which may be changed in the future. If we want to improve that, taking lock when updating restart_lsn does not work, because the initial restart_lsn is an old position copied from another slot, where the WALs could have already been removed, so unlike the mechanism mentioned in 006dd4b2, the lock cannot ensure the same. I think we might need to some other solutions for it which can be discussed separately. > > One more thing, when we copy a logical replication slot, > DecodingContextFindStartpoint reads the WAL from the specified restart_lsn > which may be removed by a concurrent checkpoint. It can produce an error > and stop slot copying, I guess. This behaviour may be not desirable. Given that we don't search for a starting point for copied slots (we pass find_startpoint=false when copying), I don't think this issue exists. Best Regards, Hou zj
