Hi Stephen, > On 13. Jul, 2020, at 18:00, Stephen Frost <sfrost@xxxxxxxxxxx> wrote: > > A pgbackrest delta restore will scan the entire data directory and > verify every file matches the last backup, or it'll replace the file > with what was in the backup that's being used. If there's an error > during any of that, the restore will fail. ok, I didn't know that. Thanks very much. I'll look into it. > That re-validation of the entire data directory is a pretty huge > difference compared to how pg_rewind works. I agree. > Ah, yes, if you rebuild the replica from a backup (or from the primary), > then sure, that's pretty similar to the pgbackrest delta restore, except > that when using delta restore we're only rewriting files that have a > different SHA checksum after being scanned, and we're pulling from the > backup repo anything that's needed and not putting load on the primary. so, from what I understand, pgbackrest bottom line merely reduces copy overhead in such a particular case. *Kind of* like shutdown primary, rsync, and then startup. > There's been a few discussions on -hackers about this, that'd probably > be the place to discuss it further.. I'm not hacker, I'm just a DBA. :-) Cheers, Paul
