Re: Postgres as In-Memory Database?

On 04/02/2014 12:32 AM, Stefan Keller wrote:

> It also mentions an insert-only technique: "This approach has been
> adopted before in POSTGRES [21] in 1987 and was called "time-travel".
> I would be interested what "time-travel" is and if this is still used by
> Postgres.

Back in the old days, PostgreSQL never deleted any tuples. Rows were
deleted by writing the deletion time into a column. As a result, you
could go back to old data just by telling PostgreSQL to report rows
which where visible at a given time.

Obviously, this approach precluded use of PostgreSQL in many scenarios.
For example, you wouldn't want to use it as your web application
session store.

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Florian Weimer / Red Hat Product Security Team