Teradata 12.0

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ctive data warehousing is the

process of mixing strategic and

operational intelligence on the same plat-

form by utilizing up-to-date enterprise

data. With active data warehousing, very

high requirements are placed on the

underlying technology.

For one, the active data warehouse

must perform considerably well on all

parts of the workload. Not only must

it manage and track a widely mixed

workload under all conditions, but it

must also be capable of managing the

flow of changing data. Second, it must

be possible to implement new applica-tions quickly and easily.

Teradata 12.0 is the next major step

toward making it easy for anyone to

build a high-performance active

data warehouse.

QWhat changes deliver new levels

of performance?

A Partitioned primary index (PPI)is extended to multiple levels,statistics are enhanced to deliver better

estimates, many query estimating and

planning improvements have been

added, and the explain plans are

extended with information that

previously had to be assumed.

Q

How does multi-level PPI

(ML-PPI) work?

A The current PPI capability allowsfor one function to determine thehorizontal partitioning of the table.With

ML-PPI, those partitioning capabilities

are extended to multiple levels. Separate

functions within ML-PPI define the parti-

tioning for each level, which can then be

utilized together or independently for much

more granular access to the desired data in

the table.

For example, an insurance company

may partition first by state, then month.Questions may be asked by state, month

or both, allowing the quantity of data

accessed to better match the requested

analysis. Reducing the data accessed reduces

the I/O load on the system and improves

overall system throughput.

QHow is statistics-based estimation

improved?

A More and varied users can submita greater assortment of queries,making accurate estimation for query

planning extremely important. Statistics

are crucial for guiding the cost-based

optimization of queries.

The number of intervals in the statistics

structure has been doubled, significantlyincreasing the detail, accuracy and under-

standing of skew. Demographics of mul-

tiple column statistics are improved with

TeradataMagazin

Teradata 12.0:Active performance

A

New release adds more value to your enterprise data warehouse.by Todd Walter with contributions from Alan Greenspan

TECH2TECH ASK THE EXPERTS

Benefits of multi-level partitioned primary index

> Increases performance of multi-

dimensional queries where the set of

constrained dimensions changes from

query to query

>Enhances performance of queries withconstraints (including range con-

straints) on multiple columns without

the overhead of secondary indexes

> Decreases the amount of I/O needed

to execute a query

> Provides an access method that

allows multiple ways to access the

data efficiently

> Allows DBAs more partitioning expres-

sions flexibility when there are multiplechoices; the DBA can define multiple

partitioning expressions and obtain

the benefits from each of them and

in combination

A.G.

PAGE 1 | Teradata Magazine | September 2007 | 2007 Teradata Corporation | AR-5386

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a better picture of how nulls appear

in the data.

Q

What happens if my statistics are

not current?

A Stale statistics can lead to invalidestimations that, in turn, can nega-tively affect query planning. Balancing the

overhead of re-collecting statistics against

the potential of inaccurate statistics often

demands trade-offs. For example, with cer-

tain columns (especially dates), it has been

necessary to collect statistics frequently to

get reasonable plans for queries at or near

the end of the data range.

Teradata 12.0 significantly reduces this

overhead by extrapolating appropriate values

when the collected statistics are not current,

thus avoiding daily collection and reducing

overall system utilization. To continue with

the above scenario, when statistics in a date

column have not been recently re-collected,

the optimizer will determine how much

additional data has been added to the table

and will extend the statistics to account for

the new date ranges. Query planning will

improve even when the statistics are not

collected every day. (See figure.)

QWhat is new in query estimation

and planning?

A Query complexity continues to risewith many nested views, subqueries,derived tables and complex joins. The

Teradata optimizer has been enhanced to

capture additional information about each

nested level in the query and then to carry

that information throughout the planning

process. Improvements have been made

to the estimation of the cost and results

of complex joins. New query rewrite

rules have been added to address many

customer-provided optimization oppor-

tunities, and the rewrite engine can now

execute in multiple passes, giving further

opportunities to improve the plan. More

accurate and consistent query plans will

be produced as a result.

QWhat changes have been made in

the explain plans?

A Size of spools, join and groupkey columns, and qualifiedreferenced object names in the query,

along with additional information, are

included in the explain plan output to

provide more information to the usersreading the explain.

QHow does Teradata improve the

ability to manage the ever-increasing

active workload?

A All of the aforementioned queryestimation accuracy improvementspull double-duty by helping the accuracy

of the workload management rules. More

information can be provided by the user

or application about each query. Work-

load exceptions have been extended and

a traffic cop has been added to automate

changes to workload rules and settings

based on user-defined or system events.

An entirely new way of accessing infor-

mation is being developed to provide

additional management information t

more data warehouse users.

QWhat is a traffic cop?

A New workload management profcan be implemented when systemconditions change or when a user-defin

event such as the end of the load wind

is reached. For example, if a system com

nent has failed or the system is exceptiobusy, the traffic cop can switch rule set

appropriately adjust the workflow base

the current system conditions.

QHow do users and applications pr

more information about the work

on the system?

A Like banding a bird to track itsflight path, a query band can nbe provided with each query. The ba

can contain any number of attribute

and values that provide detailed info

mation about the query and may be

referenced by workload managemen

rules during the query classification

phase. The information is then captu

in the query log, where it can be use

Figure Extrapolated statistics reducecollection requirements

Teradata 12.0 can extrapolate appropriate statistics values when collected statistics are not current.

As this example shows, when a query references a date beyond the range with collected statistics, tdatabase will automatically extrapolate the collected statistics to create an accurate plan. This proce

allows the reduction of frequent statistics collection while getting accurate cost-based optimizations


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future analysis of the work flowing

through the system.

Query banding is especially valuable for

applications that send work through pooled

sessions, such as traditional session pool

applications, analytic applications using

pooled sessions, business intelligence (BI)

tools and new Web service applications.

Information useful for workload manage-

ment, or for tracking the use of the data

warehouse (such as the application, work unit,

requesting user, etc.,) can be acquired through

the query banding. After the application is

adjusted to provide the information, all of

the tracking and linking to workload man-

agement is handled automatically.

QWhat new workload exceptions

are available?

A System-level workload exceptions havebeen added in Teradata 12.0. Now asingle rule can be used to raise exceptions,

regardless of the querys workload group.

Multiple rules can be assigned to a single work-

load group to allow multiple levels of control

for requests that are not behaving as expected.

QHow will systems management

information be provided in the future?

A Teradata 12.0 includes a new appli-cation programming interface (API)to make the system management informa-

tion available via standard SQL interfaces.

With this capability, data can be retrieved

and control settings altered. This makes the

information available through the standard

ODBC and JDBC interfaces.

On top of those APIs, a new system

management user interface has been

implemented. Using Web services, portal

delivered displays and a fully extensible

architecture, a fundamentally new form

of management interface is provided to

administrative and end users.

QHow will the increasing flow of change

to the data warehouse be handled?

A The continuous flow of data needsto get into the database efficiently andthen must be backed up without affecting

the flow. If availability and disaster recovery

requirements lead to a dual system implemen-

tation, the data must be synchronized with asystem in another data center.

QWhat is new for the data acquisition

and integration process?

A Many implementations use extract,load and transform (ELT) processes,which perform the transformation and

apply steps within the database, taking full

advantage of the parallel data engine to do

the work. Teradata 12.0 adds the ability to

perform bulk merge (upsert), working from

a table of change data and doing all the work

within the database.

Insert and merge operations have been

enhanced with an option to log errors to an

error table rather than initiating an abort. This

means that less effort needs to be spent on get-

ting the data perfect before applying it. Togeth-

er, these two functions significantly improve

the ELT capabilities for the warehouse.

ELT using bulk SQL operations avoids

constraints of the load utilities,allowing

greater use of physical tuning techniques

for active queries (unique secondary and

join indexes) and allowing more use of

active features (triggers, referential integrity).

QHow do we perform backup

without affecting the continuous

loading processes?

A Online Archive now allows backupsto be performed without stopping theload processes. It will automatically initiate a

checkpoint, save a log of changes and back up

the log as part of the backup. On a restore, thelog will automatically be restored and rolled

back to the checkpoint ensuring that a consis-

tent restore has been done.

QHow will the increasing volume of data

changes be synchronized?

A Teradata Replication Services has beenupgraded to significantly increase thebandwidth per replication group. Greater load

volumes and more tables can be handled by a

single replication group.

QWhat is new for building applications?

A Teradatas extensibility strategy takesseveral steps forward in Teradata 12.0,

TeradataMagazin

TECH2TECH ASK THE EXPERTS

Partitioned primary index is extended to multiple levels,

statistics are enhanced to deliver better estimates, many

query estimating and planning improvements have beenadded, and the explain plans are extended with information

that previously had to be assumed.


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allowing for more applications to be im-

plemented closer to the data in the data

warehouse. The extensibility functions will

be used to deliver Teradata functionality as

well; XML support and spatial data supportwill be the first examples.

QAre we able to wr ite our applications

in Java?

A Stored procedures (SPs) can nowbe implemented in Java.An implemen-ter can choose the ANSI Stored Procedure

Language, C/C++ or Java as the implemen-

tation language for procedures to run in the

database. Application developers who wish to

implement their entire application in Java can

write the database portion in Java as well.

QWhen can we return result sets from

Teradata stored procedures?

A Teradata 12.0 includes the ability toreturn sets of result rows from a SQLstored procedure. This will allow SPs to per-

form a wider range of application functions.

QHow can we write C/C++ proce-

dures that easily utilize data from

the warehouse?

A With a newly defined interface, itis easier to submit SQL to Teradatafrom within a C/C++ stored procedure.

This makes it simpler to utilize data from

the warehouse while also accessing external

interfaces or libraries such as connecting

to the message bus or linking to another

database engine.

Q

What if we want to return more general

result sets from a table function?

A This release includes a new methodfor defining the result row from atable function that allows the result para-

meters and data types at the invocation

time of the function.

A general-purpose function can now be

written to operate upon a more general

source of data and return data in the form

desired by each request.

QWhat else is included in Teradata 12.0?

A Many additional features addressopportunities in scalability, secur-ity, unicode support, system tools (such as

scandisk and checktable) and index wizard

support for recommending PPIs for new

or existing tables. To review the detailed

release documentation for a complete view,

visit Teradata.com/resources and select

Technical Documentation.

Activate your enterpriseTeradata has made major continuous

progress in delivering the supporting

technology for building an active data

warehouse. Each step makes it easier and

more automatic to deliver the endemic

access to integrated data that every enterprise

is demanding. Teradata 12.0 is the next major

step in that evolution, making major progress

in query planning, statistics collection, per-

formance, workload management, system

operations and extensibility.Installing and taking advantage of this tech-

nology will position your Teradata platform

for the easiest possible active data warehouse

implementation or as an extension of your

current implementation to provide more users

the data they need to deliver the best possible

value to your organization every day.T

Todd Walter, CTO, Teradata Development

Division, oversees R&D efforts for Teradata

Database software and systems. He is also

responsible for the future vision and devel-

opment of the active data warehouse.

Alan Greenspan is the product marketing

manager for Teradata Database and

load utilities. He has been with Teradata

for 15 years.

The next release of the core Teradat

product set has a new name in add

tion to a broad collection of exciting and

innovative capabilities: Teradata 12.0. N

all of the software products at the core o

the data warehouse infrastructure will ha

a consistent, unified numbering sequen

Beginning with this release, the set of

products that are designed, developed

and tested together will have a single

release number.

Teradata selected the number 12 to s

the unified numbering sequence becaus

it is the 12th major database release in

Teradatas history. This current release w

preceded by five major database releas

of Version 1 (TOS-based, Teradata

Operating System), and six major datab

releases of Version 2 (Open OS-based

UNIX, Linux and Windows).

Effective with the new release, the

numbering system will be:

> Teradata 12.0

> Teradata Database 12.0

> Teradata Tools and Utilities (TTU) 1

Teradata Database 12.0 and Teradata

Tools and Utilities 12.0 are included in thTeradata 12.0 release. The individual clie

Tools and Utilities products will also adju

to the 12.0 numbering sequence.

The term Teradata Warehouse, init

developed for use within the company,

adopted externally to package releases

and indicate system-level certification of

the various software products with differ

release numbers. This certification will

continue as an important step in the dev

opment cycle, but the unified numberin

scheme will replace the need for a sepa

rate warehouse package designation.

Minor releases will continue to be

numbered in the current method. For

example, the next major release will be

Teradata 13.0 and the minor release

following it will be Teradata 13.1.

A

Teradata 12.0: The 12tmajor database release


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Teradata 12.0