Subject Re: [ib-support] About Atomicity, Consistency, Isolation, and Durability
Author Ann W. Harrison
At 12:46 PM 2/3/2003 +0200, Pirtea Calin Iancu wrote:
>I've read recently on some page that was making a comparison between
>interbase, postgre and
>some other RDBMS that interbase is not fully ACID compliant.
>Is this true? (I think it is not but I thought I'd ask anyway)
>If it is true than in what way does it not comply?

Firebird transactions are atomic. They succeed or fail as
a group. They are durable - all changes are written out
when a transaction commits. Those two properties are well
defined. Isolation and consistency are more open topics
and are related. The InterBase/Firebird concurrency transaction
mode is consistent - they have an unchanging view of data.
Read-committed mode is available for those who prefer to give
up consistency in favor of always seeing the most current
committed version of data.

The SQL standard describes several levels of isolation -
serializable being the highest level. No database that I
know of, commercial or open source, provides serializable
transactions by default. Firebird has a mode in which it
provides serializable transactions - deadlock free. That
is not its normal mode of operation. The normal mode meets
or exceeds the requirements of the three lower isolation

So, yes, despite the rumors to the contrary, Interbase/
Firebird do provide ACID transactions.


We have answers.