Re: Oracle From a Sybase DBA perspective| What is a Database to S

Denny,

Re the Sybase Replication server: It is a separate product and truly an impressive piece of work.

While I was very impressed with Rep Server, the database is what's lacking.

Jared

PS. to all: if you've never used Sybase, you haven't developed a true appreciation for SQL*Plus.

On Sunday 31 March 2002 15:28, Denny Koovakattu wrote:
> Having worked with a lot of Sybase DBAs and having discussed why "Sybase
> Architecture is Inferior to Oracle's" and having helped them
> understand/learn Oracle, I know why Sybase DBAs find it difficult to
> understand Oracle. But there are a few things Sybase is better at.
>
> - Ablility to return result sets from procedures - Ref cursors or
> dbms_output donot match up to what Sybase offers
> - bcp out - It's time Oracle came up with some utility to extract the data
> in ascii format other than recommending "sqlplus and spool"
> - Replication - I like the Sybase replication architecture. This is a lot
> closer to what Quest offers (Shareplex).
> - Seperation of Schema and normal users. - The closest you could get to
> this is by using "alter session set current_schema". I am not familiar with
> LDAP. I believe we could be having something similar soon.
>
> If you compare the architecture of both the products, Sybase architecture
> is inferior to Oracle. My favorite is the way the transaction logs are
> managed in Sybase. Its both the rollback segments and redo logs (but only
> one log) rolled into one. Simple explanation (Unless something changed in
> one of the newer versions) - The log gets reused only after checkpointed
> transactions are cleared. Open transactions will NOT be checkpointed. But
> open transactions will not be skipped to checkpoint commited transactions.
> All it takes is one small open transaction to fill up the log. And if the
> Sybase Server goes down at this point, recovery has to start at this point,
> replaying all the transactions including commited ones. I know of cases
> where recovery took hours because of this. And the lack of rollback
> segments mean Sybase has to put a shared lock on tables during SELECTs to
> get a read consistent view of the data. But then Sybase replication may not
> work without this "architecture".
>
> I remember reading "The good thing about Oracle is it's so tunable and
> the bad thing about Oracle is it's so tunable". Change "tunable" to
> "features/options" and I guess that will explain why anybody who doesn't
> really understand the architecture find it so overwhelming. Try comparing
> Oracle Backup and Recovery options to Sybase's. Oracle has a lot of
> features/options than Sybase. Lack of understanding of the product make
> them not like the product. But I don't understand somebody not
> understanding the product after working on it for 3 years. My imagination's
> not up to the task ;)
>
> Translating Sybase lingo to Oracle is not easy. In most cases there is no
> direct match.
>
> Oracle Instance - Sybase doesn't have one
> Oracle Database - Sybase Server
> Oracle Schema - Sybase Database (Not completely true. The
> Sybase Database also has storage allocated to it. More like a minature
> database within a database. For practical purposes schema makes sense.)
> SYS User - sa User
> SYS Schema & SYSTEM tablespace - master Database
> Schema Owner - dbo User (Database Owner)
> Users (Non-Schema Owners) - Sybase Login/Users
> alter session
> set current_schema=SCHEMA - use DATABASE
> Tablespace - Segment
> Datafile - Device (There can be multiple segments on
> a singe device.)
>
> Regards,
> Denny
>
> Rachel Carmichael wrote:
> > Ian,
> >
> > Having worked with Sybase years ago, I developed this "translation"
> >
> > Sybase instance = Oracle database
> > Sybase database = Oracle tablespace
> > Sybase dbo user = Oracle sys user
> > Sybase master database = Oracle SYSTEM tablespace
> >
> > anyone have a better explanation?
> >
> > Rachel
> >
> > --- "MacGregor, Ian A." <ian_at_SLAC.Stanford.EDU> wrote:
> > > Well, that certainly was interesting!! No database will always
> > > compare favorably to others for every feature. There are some tings
> > > SYBASE does better than Oracle. However, he is either ignorant of
> > > such things as the "no logging" directive, or refuses to consider
> > > them because they are not part of SYBASE. I believe that is his real
> > > point, Oracle ain't Sybase. If methods to accomplish a task differ
> > > Oracle's way is wrong. Oracle has lagged other database vendors in
> > > facilitating getting the data out of the database, while doing a
> > > superior job of lessening the chances of losing data.
> > >
> > > Perhaps someone with SYBASE experience can explain exactly what a
> > > database is to Sybase. I infer from the posting that having
> > > thousands of them on a single server is common place. I imagine it's
> > > the opposite of parallel server: instead of multiple instances
> > > associated with a single set of database files, a single instance is
> > > associated with multiple sets of database files. Each set of files
> > > being a database.
> > >
> > > Ian MacGregor
> > > Stanford Linear Accelerator Center
> > > ian_at_slac.stanford.edu
> > >
> > > -----Original Message-----
> > > Sent: Friday, March 29, 2002 10:43 AM
> > > To: Multiple recipients of list ORACLE-L
> > >
> > >
> > > Dear list,
> > >
> > > Feel like having a good rant? Need to take some frustrations
> > > out on lies, ignorance and misinformation?
> > >
> > > I received a document from a friend that live in both the Sybase
> > > and Oracle worlds. He was interested in my comments on it
> > > as he recognized it as a rant against Oracle that was full of
> > > misinformation.
> > >
> > > Oracle has it's problems, but if you want to rant about it's
> > > inadequacies, you should at least be accurate.
> > >
> > > Some of the things in here I can't address, such as the
> > > IEEE number formats.
> > >
> > > Others are just plain stupid.
> > >
> > > The writer claims to have spent 3 years with Oracle, but he's
> > > either lying or extraordinarily incompetent, I dunno which.
> > >
> > > Here's my proposal: I'm turning this document loose to the list.
> > > I was going to comment on it myself, but it's fairly lengthy, and I
> > > just don't have time to do it myself.
> > >
> > > Besides, I know that some of you relish such opportunities. :)
> > >
> > > It's in MS Word format. If you want to make comments about
> > > any section of the document, include your comments in blue
> > > font below that section.
> > >
> > > I will compile the comments, and send the annotated document
> > > back to my friend. He can distribute it to his Sybase DBA friends
> > > if he likes.
> > >
> > > I was kidding about the ranting. Please keep it objective and
> > > professional.
> > >
> > > Please include your name at the top of the document. Tell me if
> > > you want your name and email address included in the finished
> > > document.
> > >
> > > The document can be found at:
> > >
> > > http://www.cybcon.com/~jkstill/Oracle_from_a_Sybase_DBA.doc
> > >
> > > Thanks,
> > >
> > > Jared

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Jared Still
  INET: jkstill_at_cybcon.com

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