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