Hi Raja, Thanks for the patch. I tried v1 (cfbot branch cf/7587, commit 8dda72e) on Ubuntu 26.04 (WSL2), applied on master c1694b7. It applied cleanly with git apply and pg_combinebackup rebuilt fine. The build was --without-icu and without TAP tests.
I used a small script (attached as repro.sh) with initdb --no-data-checksums, summarize_wal=on, a full backup, pg_checksums --enable on the stopped cluster, then an incremental backup and pg_combinebackup. Before (master): pg_combinebackup: error: only some backups have checksums enabled pg_combinebackup: hint: Take a new full backup after changing the data checksum state with pg_checksums. (exit=1) After (v1): pg_combinebackup: error: only some backups have checksums enabled pg_combinebackup: hint: Take a new full backup after changing the data checksum state. (exit=1) I got the same before/after result for the online case. There I took a full backup with checksums off, ran pg_enable_data_checksums(), waited for data_checksums=on, took an incremental backup, and ran pg_combinebackup. The full backup's control file shows data_checksum_version 0 and the incremental shows 1. Observations: - The new hint matches the behaviour, since the check also triggers after online enabling and the old hint pointed only at pg_checksums. - The hint is now less actionable. A reader gets the "what" (take a new full backup) but not how the state changed. That seems fine to me, but you could keep it explicit, for example "after enabling or disabling data checksums". I did not test a backup chain across a disable. - The doc xref checksums-online-enable-disable exists in wal.sgml. I could not build the docs here (xmllint is missing), so the SGML change is only read, not rendered. - The new doc text says the chain is refused for backups taken "while they were still being enabled". I did not test that intermediate state, so I cannot confirm that sentence from a run. - I did not run the pg_combinebackup TAP tests (IPC::Run not available), and a grep for "data checksum state" in src/bin/pg_combinebackup/t finds no test for this hint, so a small test for the error/hint might be worth adding. - src/bin/pg_combinebackup/po exists, so the translations may need an update; I did not check the .po files. Thanks again, João Rito
repro.sh
Description: Binary data
