Re: Hot Backup with rsync fails at pg_clog if under load

>> But on the standby its size is the old one (thus, it seems, that the size
>> changed after the rsync transfer and before the pg_stop_backup() was
>> called):

> Now that seems pretty weird - I don't think that file should ever shrink.

It seems, I was not clear in my last example. The pg_clog file doesn't shrink. On the contrary, when rsync kicks in it is still small, but after it completes and somewhere around the pg_stop_backup() call, the pg_clog file grows on the master. Hence, it is left smaller on the standby.

> Are you sure that the rsync isn't starting until after
> pg_start_backup() completes?

100% - the procedure is scripted in a single threaded application, so rsync is started only after pg_start_backup(...) returns.

> Because if you were starting it just a
> tiny bit early, that would explain the observed symptoms perfectly, I
> think.

I agree, but that is not the case.