On Mon, May 8, 2023 at 4:10 AM Evgeny Morozov <postgresql3@xxxxxxxxxxxxxxxxx> wrote: > On 6/05/2023 11:13 pm, Thomas Munro wrote: > > Would you like to try requesting FILE_COPY for a while and see if it eventually happens like that too? > Sure, we can try that. Maybe you could do some one way and some the other, so that we try to learn more? > Ubuntu 18.04.6 > Kernel 4.15.0-206-generic #217-Ubuntu SMP Fri Feb 3 19:10:13 UTC 2023 > x86_64 x86_64 x86_64 GNU/Linux > zfsutils-linux package version 0.7.5-1ubuntu16.12 amd64 I tried for a few hours to reproduce this by trying to make as many things as similar to yours as I could based on info in this thread (Linux: up-to-date Ubuntu 18.04 in vagrant which has nearly the same kernel 4.15.0-208-generic and a close but slightly different version of ancient ZFS 0.7.5-1ubuntu15, not sure why, ZFS: mirror (I used a pair of loopback files), recordsize=16kB, compression=lz4, PG: compiled from tag REL_15_2, data_checksums=on, full_page_writes=off, wal_recycle=off, wal_init_zero=off), with what I thought might be roughly what you're doing (creating three DBs, two clones of the first, with various modification at various points, with various overlapping activities, and then checking for catalog corruption). No cigar. Hrmph.