Re: Materialized views WIP patch

On 11/19/12 9:57 AM, Josh Berkus wrote:
> Kevin,
> 
>> I'm looking at whether there is some reasonable way to detect invalid
>> data as well as capture age of data. Every solution I've thought of
>> so far has at least one hard-to-solve race condition, but I have
>> hopes that I can either solve that for one of the ideas, or come up
>> with an idea which falls more gracefully under MVCC management.
> 
> What's the race condition?  I'd think that LOAD would take an exclusive
> lock on the matview involved.

BTW, another thought on the timestamp: while it would be better to have
a lastrefresh timestamp in pg_class, the other option is to have an
extra column in the matview (pg_last_update).  While that would involve
some redundant storage, it would neatly solve the issues around unlogged
matviews; the timestamp and the data would vanish at the same time.

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