Re: Production block comparison facility

On 22 July 2014 12:54, Greg Stark <stark@mit.edu> wrote:
> If you're always going FPW then there's no point in the rest of the record.

I think its a simple matter to mark them XLP_BKP_REMOVABLE and to skip
any optimization of remainder of WAL records.

> The point here was to find problems so that users could run normally with
> confidence.

Yes, but a full overwrite mode would provide an even safer mode of operation.

> The cases you might want to run in the mode you describe are the build farm
> or integration testing. When treating your application on the next release
> of postgres it would be nice to have tests for the replication in your
> workload given the experience in 9.3.
>
> Even without the constant full page writes a live production system could do
> a FPW comparison after a FPW if it was in a consistent state. That would
> give standbys periodic verification at low costs.

Yes, the two options I proposed are somewhat independent of each other.

-- Simon Riggs                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services