July 7, 2008

EnterpriseDB’s itemized claims of Oracle compatibility

Obviously, I’m poking around EnterpriseDB’s site this morning (in connection with their status as my client, actually). Anyhow, we all know that one of EnterpriseDB’s core claims is great Oracle-compatibility — but what exactly do they mean by that? I found a fairly clearly laid-out answer, as of last year, in this white paper and and — even more simply — in this blog post summarizing the white paper.


3 Responses to “EnterpriseDB’s itemized claims of Oracle compatibility”

  1. Daniel Weinreb on July 8th, 2008 6:44 am

    One thing I’ve always wanted to know is whether EnterpriseDB’s Oracle compatibility includes being compatible with Oracle’s unusual isolation mode. Oracle concurrency control works differently from any other DBMS I’ve ever seen. The fact that read locks do not conflict with write locks sounds great, and sometimes is great, but the consequences of the complete set of rules can be rather counterintuitive, and it’s hard to get true ACID behavior. It seems to me that this would be hard to emulate using an underlying DBMS that works in a more conventional fashion.

  2. Serge Rielau on July 8th, 2008 7:25 am


    Actually Oracle’s unusual isolation mode isn’t all that special anymore. And yes, enterpriseDB does support it AFAIK.
    Also let’s not confuse concurrency control with isolation. E.g. IBM Informix IDS achieve “readers don block writers and writers don’t block readers” without the need for Snapshot isolation.
    In my experience with Oracle migrations teh vast majority of users, in the end require compatible locking behavior. “statement level isolation” (Oracle’s default) provides only “another shade of grey” compared to “cursor stability” in a multi-statement transaction.

    Serge Rielau
    IBM Toronto Lab

  3. Paul Johnson on April 22nd, 2009 9:58 am

    Terdata supports readers/writers not blocking each other through the use of ‘access’ or ‘dirty read’ locks. Without this capability being fully exploited by the DBA through appropriate user views a lot of queries spent time queued and not running, and the user just thinks performance is sucky.

Leave a Reply

Feed: DBMS (database management system), DW (data warehousing), BI (business intelligence), and analytics technology Subscribe to the Monash Research feed via RSS or email:


Search our blogs and white papers

Monash Research blogs

User consulting

Building a short list? Refining your strategic plan? We can help.

Vendor advisory

We tell vendors what's happening -- and, more important, what they should do about it.

Monash Research highlights

Learn about white papers, webcasts, and blog highlights, by RSS or email.