Re: Quote from comp.object
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Fri, 02 Mar 2007 23:30:40 GMT
Message-ID: <As2Gh.4785$PV3.44544_at_ursa-nb00s0.nbnet.nb.ca>
>>On Feb 28, 10:37 am, Sampo Syreeni <d..._at_iki.fi> wrote:
>>
>>>[snip] Hence, the RM places little to no constraints on optimization.
>>I agree with Sampo's onservations, with one practical caveat.
>>
>>One principle objective of relational DBMS systems is to separate data
>>management from application code, allowing several applications to
>>share one database. This leads to situations where the DBMS is
>>implemented as one set of (operating system) processes, and the
>>application(s) in another(others).
>>
>>Most hierarchical systems--IMS, Pick etc -- share with many embedded
>>data managers -- Berkeley DB, etc -- the property that the data
>>management is co-resident with the application code in a single
>>process. By avoiding the cost of moving data between processes,
>>hierarchical data managers adopting this architecture gain
>>considerable response time and throughput advantages.
>>
>>That said, it doesn't amount to a hill of beans in practice. Business
>>flexibility trumps computer performance every time (so long as
>>performance meets some minimal, usually pretty low-bar, level).
Date: Fri, 02 Mar 2007 23:30:40 GMT
Message-ID: <As2Gh.4785$PV3.44544_at_ursa-nb00s0.nbnet.nb.ca>
Walt wrote:
> "DBMS_Plumber" <paul_geoffrey_brown_at_yahoo.com> wrote in message > news:1172776674.096197.42640_at_k78g2000cwa.googlegroups.com... >
>>On Feb 28, 10:37 am, Sampo Syreeni <d..._at_iki.fi> wrote:
>>
>>>[snip] Hence, the RM places little to no constraints on optimization.
> > [snip] >
>>I agree with Sampo's onservations, with one practical caveat.
>>
>>One principle objective of relational DBMS systems is to separate data
>>management from application code, allowing several applications to
>>share one database. This leads to situations where the DBMS is
>>implemented as one set of (operating system) processes, and the
>>application(s) in another(others).
>>
>>Most hierarchical systems--IMS, Pick etc -- share with many embedded
>>data managers -- Berkeley DB, etc -- the property that the data
>>management is co-resident with the application code in a single
>>process. By avoiding the cost of moving data between processes,
>>hierarchical data managers adopting this architecture gain
>>considerable response time and throughput advantages.
>>
>>That said, it doesn't amount to a hill of beans in practice. Business
>>flexibility trumps computer performance every time (so long as
>>performance meets some minimal, usually pretty low-bar, level).
> > Hear, hear! > > I've never seen the above quite so well put, especially the part concening > the minimal performance bar.
If we had true physical independence, even the process context switches could mostly go away. Received on Sat Mar 03 2007 - 00:30:40 CET