Am I missing something here?
Comparing 'EJB' to 'TP', don't we mean _entity_ EJB when discussing
transactional capabilities? ND5.x doesn't support entity EJB, right? And,
never will?
-- Curt Springer, tND
At 04:18 PM 11/18/99 -0800, Brendan Johnston wrote:
>1. A TP is essential if you want to manage transactions which span more
>than one database
>2. A TP also enables components to be written without managing
>transactions themselves which allows them to be wired together in a variety
>of ways
>3. A TP has security features (who is this client, can this method be
>called by this client)
>4. A TP manages server resources i.e. it can pool database connections
>etc.
>
>A fully compliant EJB server provides this stuff too. ND does 2, 3 and 4
>for EJBs although I don't think it does 1.
>
>A transaction which spans multiple databases requires a 2 phase commit,
>which is less efficient than a transaction contained within one database.
>
>The transactions which last the entire length of an EJB method call may be
>larger than is necessary reducing concurrency from the optimal.
>If you use CORBA with a transaction service, security service etc. you
>essential have EJB.
>
>Tuxedo would have a lot of management and monitoring tools. It would
>probably have means to tune and configure it etc.
>
>If your environment involves one database and one application server you
>don't need a TP monitor. A TP monitor is useful for large complex sites.
>
>Brendan
>
>
>
> -----Original Message-----
> From: Gregory Bohmer [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, November 18, 1999 12:22 PM
> To: [EMAIL PROTECTED]
> Cc:
>[EMAIL PROTECTED]
> Subject: Re: [ND] TP's and NetD
>
> This is a great discussion. I'm glad I started it! I like
>your
> bottom line questions here Janet - I also look forward to
> responses on these from those who know it better...
>
> Regards,
> Gregory
>
>
> [EMAIL PROTECTED] wrote:
>
> > Hi Brendan,
> >
> > Thanks VERY much!
> >
> > New ones:
> > So with BEA WebLogic, if you are using the EJB
>capabilities, you really need to
> > use Tuxedo with it for high performance database access?
>(or else plug in some
> > other TM-like service?)
> >
> > How about in ND5.x.....if the app is using EJBs to do db
>stuff, is there any TM
> > involved? Or does the ND5 EJB architecture still somehow
>manage to let the RDBMS
> > handle it like ND4 does?
> >
> > Lastly, what are we really saying here?
> > Do you think an EJB server + TM processes concurrent
>database requests as
> > efficiently as the plain Corba-based
>"let-the-db-manage-all-the-db-action" (not
> > sure the correct term?!) services that ND4 uses?
> >
> > Many thanks!
> > Janet
> >
> >
> > (Embedded
> > image moved Brendan Johnston
> > to file: <[EMAIL PROTECTED]>
> > pic02195.pcx) 11/18/99 02:26 PM
> >
> >
> > To: Janet Traub/IS/SSC/THD,
> >
>[EMAIL PROTECTED]
> > cc:
> > Subject: RE: [ND] TP's and NetD
> >
> > Hi Janet,
> >
> > To answer your question,
> >
> > With any database or any EJB server, writes queue and
>happen one at a time.
> >
> > To go further,
> >
> > Writes happen one at a time with all databases.
> > Writes happen one at a time with EJB.
> >
> > Any number of reads can happen simultaneously with all
>databases.
> > One read happens at a time with EJB.
> >
> > With some databases reads can happen simultaneously with
>uncommitted writes
> > and the older committed version of data is returned.
> > With EJB reads do not happen simultaneously with writes.
> >
> > >From the point of view of concurrency, some databases are
>better than
> > others, all EJB servers are worse than any major database.
> > >From other points of view EJB servers have advantages.
> >
> > Brendan
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED]]
> > Sent: Thursday, November 18, 1999 10:10 AM
> > To:
> > [EMAIL PROTECTED]
> > Subject: Re: [ND] TP's and NetD
> >
> > << File: pic06777.pcx >>
> >
> > Thanks Brendan. So is this statement:
> >
> > > Oracle will serialize 200 requests to update
>one row.
> >
> > explained by this passage:
> >
> > " This enables read only users of the database
>to view the
> > old
> > committed changes to the database while other
>uncommitted
> > changes are made. This makes it possible for
>reads of a
> > database to never block."
> >
> > or did you just mean it "queues" up the 200
>requests to
> > update the same row and
> > processes them one by one?
> >
> > Thanks,
> > Janet
> >
> > (Embedded
> >
> > image moved Brendan Johnston
> >
> > to file:
><[EMAIL PROTECTED]>
> >
> > pic06777.pcx) 11/18/99 12:40 PM
> >
> > To: 'Aby Mathew' <[EMAIL PROTECTED]>
> > cc:
> > [EMAIL PROTECTED]
>(bcc: Janet
> > Traub/IS/SSC/THD)
> > Subject: Re: [ND] TP's and NetD
> >
> > Relational databases have locking and
>concurrency built in.
> > If one user has an uncommitted change to a row,
>other
> > attempts to update the
> > row will block until the first user commits or
>rolls back.
> >
> > Unlike EJB servers, databases have separate read
>and write
> > locks, deadlock
> > detection and resolution. There are tools in
>most
> > relational databases to
> > kill particular processes, to determine how many
>locks a
> > process holds, how
> > much IO and CPU a process is using, to
>automatically kill
> > processes which
> > use more than some limit of locks, CPU, IO etc
>for the user
> > or session.
> >
> > Some databases (Yes - Oracle, PostgreSQL, Solid,
>Interbase.
> > Not - DB2,
> > MSSQL, Sybase) have versioning. This enables
>read only
> > users of the
> > database to view the old committed changes to
>the database
> > while other
> > uncommitted changes are made. This makes it
>possible for
> > reads of a
> > database to never block.
> >
> > EJB's are typically non reentrant. This reduces
> > concurrency.
> >
> > Brendan
> >
> > -----Original Message-----
> > From: Aby Mathew
> > [mailto:[EMAIL PROTECTED]]
> > Sent: Wednesday, November 17, 1999
>5:43 PM
> > To: 'Brendan Johnston'
> > Cc:
> >
>[EMAIL PROTECTED]
> > Subject: RE: [ND] TP's and NetD
> >
> > Brendan,
> >
> > Could you elaborate a little on this:
> > > Oracle will serialize 200 requests
>to update one
> > row.
> >
> > Thanks,
> > Aby
> >
> > > -----Original Message-----
> > > From: Brendan Johnston
> > [mailto:[EMAIL PROTECTED]]
> > > Sent: Wednesday, November 17, 1999
>2:44 PM
> > > To: Gregory Bohmer
> > > Cc:
> >
>[EMAIL PROTECTED]
> > > Subject: Re: [ND] TP's and NetD
> > >
> > >
> > > Gregory,
> > >
> > > Standard WebLogic does not come with
>Tuxedo.
> > > Oracle will serialize 200 requests
>to update one
> > row.
> > >
> > > Brendan
> > >
> > >
> > > -----Original Message-----
> > > From: Curt Springer
> > >
>[mailto:[EMAIL PROTECTED]]
> > > Sent: Wednesday,
>November 17, 1999
> > 11:56
> > AM
> > > To: Gregory Bohmer
> > > Cc:
> > >
> > [EMAIL PROTECTED]
> > > Subject: Re: [ND] TP's and
>NetD
> > >
> > > Standard ND (not using PACs,
>EJBs, just
> > using RDBMS/JDBC
> > > service) has no
> > > concept of data integrity,
>AFAIK. It
> > only
> > manages
> > > resources, i.e., how
> > > many requests are
>outstanding, and how
> > many
> > db
> > > connections
> > > are available at
> > > the moment. What those
>requests are
> > doing
> > is somebody
> > > else's department.
> > >
> > > - Curt Springer, Team ND
> > >
> > >
> > > At 02:39 PM 11/17/99 -0500,
>Gregory
> > Bohmer
> > wrote:
> > > >Here's a general question
>for
> > everybody. I
> > recognize
> > > >that BEA WebLogic uses
>their own TP
> > Monitor
> > called
> > > >Tuxedo to help queue
>update/delete
> > requests, and ensure
> > > >data integrity. What does
>NetD use?
> > For
> > instance,
> > > >if 200 threads on the
>server (from
> > client
> > > calls) are all
> > > trying
> > > >to simulataneously update
>the same row
> > in
> > the
> > > underlying
> > > >Oracle database, what kind
>of queuing
> > and
> > the like are
> > > >occuring in the NetD app
>server?
> > > >
> > > >How does this translate to
>the
> > PeopleSoft
> > PAC?
> > > >
> > > >Thanks as always.
> > > >
> > > >Regards,
> > > >Gregory, HHMI
> > > >
> > >
> > >
> >
> >
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> > >
> > >
> >
> >
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>------------------------------------------------------------------------
> > Name: pic02195.pcx
> > pic02195.pcx Type: PCX Image
>(application/x-unknown-content-type-pcxfile)
> > Encoding: base64
>
>
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