Re: Unlogged vs. In-Memory

Thom Brown <thom@linux.com>

From: Thom Brown <thom@linux.com>

To: Joshua Berkus <josh@agliodbs.com>

Cc: "Jehan-Guillaume (ioguix) de Rorthais" <ioguix@free.fr>, damien clochard <damien@dalibo.info>, Roy Hann <specially@processed.almost.meat>, pgsql-advocacy@postgresql.org, Rob Wultsch <wultsch@gmail.com>

Date: 2011-05-05T17:15:15Z

Lists: pgsql-hackers

On 5 May 2011 18:09, Joshua Berkus <josh@agliodbs.com> wrote:
> All,
>
> FWIW, I wasn't planning to change the name of the feature (although Volatile Tables has a certain appeal).   We also have a duty to our users not to mislead them, and "Unlogged tables" does say something about the durability of their data.   The last thing we want is for users to repeat the MyISAM experience with PostgreSQL.  Also, we're not changing the syntax for declaring one at this point.
>
> My query to this list was mostly about how we *describe* Unlogged Tables for the press.  I have the same questions about a few other features, but we seem to have hammered out SSI.
>
> I feel like the consensus is that we can describe Unlogged Tables as "similar to in-memory tables" without misleading anyone.

Saying "similar to in-memory tables" sounds immediately misleading to
me.  If I didn't know any better, I'd assume:

- the table is kept in memory
- no data ever written to disk
- all data lost upon stopping the service

None of these are true.

Thom