1. TERADATA RDBMS ARCHITECTURE
DECEMBER 2003
TERADATA Training

2. Teradata RDBMS Architecture
Objective of this training is to understand
Teradata RDBMS hardware components
Teradata Software Architecture
DECEMBER 2003
TERADATA Training

3. HARDWARE COMPONENTS
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TERADATA Training

4. Hardware Components
The hardware that supports Teradata RDBMS software is based on off
the-shelf Symmetric Multiprocessing (SMP) technology.
Hardware Components are:
SMP Systems
An SMP system consists of a single Processor Node.
MPP Systems
An MPP is a configuration of two or more loosely coupled SMP nodes
BYNET
Hardware inter processor network to link nodes on an MPP system.
DECEMBER 2003
TERADATA Training

5. Processor Nodes
A Processor Node is a hardware assembly containing several, tightly
coupled central processing units (CPUs).
SMP configuration comprises of a single processor node that is connected
to one or more disk arrays with:
Database software
Client interface software
Operating system
Multiprocessor shared-memory processors
Failsafe power provisions.
DECEMBER 2003
TERADATA Training

6. BYNET
Connects processors by broadcast or point-to-point communication, depending on the situation.
MPP Systems: BYNET is a hardware inter processor network to link nodes on an MPP system.
SMP Systems: BYNET is a software-configured virtual BYNET driver to implement services on a Single-node SMP system.
DECEMBER 2003
TERADATA Training

7. VPROCS
VPROCS are a set of software processes that are run on a node by both,
SMP and MPP machines.
Two types of VPROCS are:
Parsing Engine (PE )
Performs session control and dispatching tasks as well as
parsing functions.
Access Module Processor (AMP)
Performs database functions to retrieve and update data on
the virtual disks (vdisks)
DECEMBER 2003
TERADATA Training

8. Disk Arrays
A disk array is a matrix of independent but interconnected physical
disk storage units.
For the Teradata RDBMS, the disks are organized as a Redundant
Array of Independent Disks (RAID), as RAID 1 (mirroring), or as
RAID 5 or RAIDS (parity) technology using RAID Manager.
Each array typically consists of from one to four ranks of disks, with
up to five disks per rank.
DECEMBER 2003
TERADATA Training

9. Disk Arrays - Related Terminology
Drive Groups - A drive group is a set of drives that have been configured into one or more logical units(LUNs).
LUN - An LUN is a portion of every drive in a drive group. This portion is configured to represent a single UNIX disk.
Pdisks - 2A pdisk is a slice of LUN that is assigned to an AMP. Each pdisk is uniquely identified and independently addressable.
Virtual Disks (vdisks) - The group of pdisks assigned to an AMP is collectively identified as a vdisk. A vdisk is used to control the assignment of pdisks to an AMP.
DECEMBER 2003
TERADATA Training

10. Cliques The clique is a feature of multinode systems that physically
groups nodes together by
multiported access to common disk
array units.
Inter-node disk array connections
are made using SCSI buses.
The nodes do not share data. They
only share access to the disk
arrays.
DECEMBER 2003
TERADATA Training

11. SOFTWARE ARCHITECTURE
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TERADATA Training

12. Software Architecture
Teradata Software Architecture comprises of the following components:
Parallel Database Extensions (PDE)
Teradata File System
Trusted Parallel Applications
Virtual Processors - PE and AMP
Teradata Director Program
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TERADATA Training

13. Parallel Database Extension(PDE)
The PDE software is an interface layer on top of the operating
system.
The PDE provide the ability to:
Execute vprocs (virtual processors)
Run the Teradata RDBMS in a parallel environment
Apply a flexible priority scheduler to Teradata RDBMS sessions
Debug the operating system kernel and the Teradata RDBMS using resident debugging facilities.
The PDE also enable an MPP system to:
Take advantage of hardware features such as the BYNET and
shared/reliable disk arrays.
Process user applications written for an operating system (on nodes and disks different from those configured for the parallel database)
DECEMBER 2003
TERADATA Training

14. Teradata File System TERADATA Training
The special-purpose Teradata file system is a layer of software between
the Teradata RDBMS layer and the PDE layer. Teradata file system
service calls allow the Teradata RDBMS to store and retrieve.
Teradata file system is significantly different from traditional
database file systems.
In the Teradata system the rows of every table (system as well as
user) are distributed evenly across all AMPs/Vdisks (assuming
proper Primary Index selection.) Every table has some rows on
each and every AMP. Each AMP places, maintains and manages
the rows on its corresponding Vdisks.
This distribution allows the data to be accessed in parallel and provides a
better basis for MPP operations.
DECEMBER 2003
TERADATA Training

15. Physical Data Block Layout
Individual rows are stored in data blocks.Data blocks in a given
table do not have to be of the same size.
They can range from 1 to 256 sectors in length.
There is a maximum block size for multi row blocks.
Advantages due to Teradata blocking strategy are that unused space in
the blocks never exceeds 511 bytes, data blocks are never chained , so
there can never be broken pointer chains and a traditional reorganization
due to block split fragmentation is never needed.
DECEMBER 2003
TERADATA Training

16. PERM Space and SPOOL Space
The maximum amount of storage assigned to a user or database
for holding table rows, Fallback of these tables, secondary index
subtables and permanent journals is called PERM space.
SPOOL Space
Temporary space acquired automatically by the system and used for work
space and answer sets for intermediate and final results of Teradata SQL
statements (e.g. SELECT statements generally use Spool space to store
the SELECTed data) is called SPOOL space.
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TERADATA Training

17. Trusted Parallel Applications(TPA)
TPA is a special class of tasks provided by the PDE.
On an SMP or MPP system, the TPA is the Teradata RDBMS.
On an MPP system, the TPA services include:
Facilities to manage parallel execution of the TPA on multiple nodes.
Dynamic distribution of execution processes.
Coordination of all execution threads, whether on the same or on different nodes
Balancing of the TPA workload within a clique
Resident debugging facilities in addition to kernel and application debuggers
A Dump Freeze Elimination feature in which all nodes remain available on the BYNET while the systems captures a PDE dump.
DECEMBER 2003
TERADATA Training

18. VPROCS Vprocs are a set of software processes that run on a node
under the Teradata Parallel Database Extensions (PDE) within the
multitasking environment of the operating system.
Each vproc is a separate, independent copy of the processor
software, isolated from other vprocs, but sharing some of the
physical resources of the node, such as memory and CPUs. Multiple
vprocs can run on an SMP platform or a node.
There are two types of VPROCS -
Parsing Engine (PE) and Access Module Processor (AMP)
DECEMBER 2003
TERADATA Training

19. Parsing Engine(PE) The Parsing Engine is the virtual
processor that communicates with
the client system on one side and
with the AMPs (via the BYNET or
Boardless BYNET) on the other
side.
PE elements are:
Parser (including Optimizer)
Dispatcher
Session Control
DECEMBER 2003
TERADATA Training

20. Access Module Processor(AMP)
The Access Module Processor
(AMP) is the heart of the Teradata
RDBMS.
The Access Module Processor is a
virtual processor (vproc)
that provides a BYNET interface
and performs many database and
file-management tasks.
Each AMP is assigned a portion of
the database to control.
Each AMP also maintains and
stores its portion of the database
tables on disks.
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TERADATA Training

21. PE Routing of Teradata SQL Request Messages
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TERADATA Training

22. Teradata Director Program
Teradata Director program (TDP) provides all data comunication
management.
The TDP does the following procedures:
Establishes and manages session control
Routes requests
Routes logons
Verifies users
Initiates recovery and restart processing
Monitors and controls security
DECEMBER 2003
TERADATA Training

23. Logical Database Components
There are five fundamental objects which may be found in a Teradata
database.
Tables - rows and columns of data
Views - predefined subsets of existing tables
Macros - predefined, stored SQL statements
Triggers - SQL statements associated with a table
Stored Procedure - program stored within TD
These objects are created, maintained and deleted using Structured Query
Language (SQL).
Object definitions are stored in the Data Dictionary Directory (DD/D).
A Teradata database is a defined logical repository for tables, views, macros, SPs.
A Teradata user is a database with an assigned password.
DECEMBER 2003
TERADATA Training