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

On 22-09-2011 11:24, Linas Virbalas wrote:
> In order to check more cases, I have changed the procedure to force an
> immediate checkpoint, i.e. pg_start_backup('backup_under_load', true). With
> the same load generator running, pg_start_backup returned almost
> instantaneously compared to how long it took previously.
>
> Most importantly, after doing this change, I cannot reproduce the pg_clog
> error message anymore. In other words, with immediate checkpoint hot backup
> succeeds under this load!
>
Interesting. I remembered someone reporting this same problem but it was not 
reproducible by some of us.

> Do you have ideas why does the Hot Backup operation with
> pg_start_backup('backup_under_load', true) succeed while
> pg_start_backup('backup_under_load') fails under the same load?
>
I don't but if you show us the output of the steps above...

> If needed, I could do that, if I had the exact procedure... Currently,
> during the start of the backup I take the following information:
>
Just show us the output of pg_start_backup and part of the standby log with 
the following message 'redo starts at' and the subsequent messages up to the 
failure.


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