RE: Data modeling Tablespace mapping, Re-org
- From: "Hollis, Les" <Les.Hollis@xxxxxx>
- To: <DWILLIAMS@xxxxxxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 1 Dec 2004 10:45:43 -0600
Your table design and entity relationship starts with the data modeler.
It should be reviewed by your physical DBA.
Once the ER diagram is set and all parties agree (i.e. Developers,
Data Modeler AND your physical DBA) , then the whole thing gets turned
over to your Physical DBA.
It then becomes his job to take the ER diagram and most efficiently lay
out the tables in tablespaces that will most efficiently use the
available disk and hardware setup.
The DBA works closely with the System Admins (in some cases this MAY be
the same person...I've handled both roles at the same time on one or two
occasions), to set up file systems (or raw partitions) to provide the
best performance and reliability (i.e. RAID 0+1, RAID [yuck] 5, etc.).
Where are the online redo log files going to be, where are my archive
logs? Don't forget to put Temp tspace and undo tspace on slightly used
filesystems. This is where all of the good attributes of a DBA come
into play. I've always felt that the best physical DBA's used to be (or
still are) good System Admins. They understand the physical hardware
and how it all interacts and have a good understanding of the operating
system.
The DBA should consider estimated growth and size of tables and the
interactivity of them to decide where to place each table.
A good physical DBA can make worlds of difference in performance based
on the placement of his datafiles and what tables are in those files.
Just my 2 cents worth.........
<< We cannot move forward with any tablespace reallocations unless it
starts within the DDL process from development all the way to
production. Tablespaces are defined from within the data model
process, starting from when a table is created. >>
GARBAGE..........developers have NO clue as to the relationship of
tables to tablespaces to datafiles to segments to extents to data
blocks. Their job is to develop the business plan into the logical
design on the application....not to determine the physical layout of the
database.
This management has obviously come from the ranks of
developers...........and want to maintain their micromanage control.
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