Re: Re: xReader, double-effort (was: Temporary tables under hot standby)

> That's an interesting point. Out of curiosity, how did the
> corruption originate?

We're still not sure. It appears to be in the system catalogs, though.
Note that the original master developed memory issues.

> It suggests a couple questions:
>
> (1) Was Slony running before the corruption occurred?

No.

> If not, how
> was Slony helpful?

Install, replicate DB logically, new DB works fine.

> (2) If logical transactions had been implemented as additions to
> the WAL stream, and Slony was using that, do you think they would
> still have been usable for this recovery?

Quite possibly not.

> Perhaps sending both physical and logical transaction streams over
> the WAN isn't such a bad thing, if it gives us more independent
> recovery mechanisms. That's fewer copies than we're sending with
> current trigger-based techniques.

Frankly, there's nothing wrong with the Slony model for replication
except for the overhead of:
1. triggers
2. queues
3. Running DDL

However, the three above are really big issues.

--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com