Transaction Processing

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Transaction Processing

• Chapter 15 - 18

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Ch. 15 - Transaction Basics

• 15.1 ACID
• 15.2 Models

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15.1 ACID

• Transaction - collection of actions imbued with
  ACID properties
• ACID
• Atomic
• Consistent
• Isolated
• Durable

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15.2 Transaction Models

• Flat
• Distributed Flat
• Chained
• Nested

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Flat Model

• Start, commit, abort (or rollback)
• Great for banking transactions
• ACID
• 2-3 seconds
• Records are locked while it happens
• Short transactions (see baby steps)

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Distributed Flat Model

• Still flat - but over multiple databases
• Transaction Processing Monitors assist (TP
  monitors)
• Might use a two-phase commit (pg 327)
• Uses lots of overhead
• Problems if initiating machine dies

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Limitations of Flat

• Cannot do partial rollback
• Bulk transactions
• Independent transactions (pg 329)
• Humans in the loop gt long transactions
• Multiple companies - want to control their own TP
  monitors

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Chained transactions

• Syncpoints (not durable)
• Periodic saving
• Chained (durable)
• Commit in pieces
• No rollback
• SAGA
• Allows complete rollback but still saves
  periodically

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Nested Transactions

• Break transactions into sub transactions
• Page 335

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Ch 16 - TP Monitors

• 16.1 TP Monitor Basics
• 16.2 TP Monitor Benefits
• 16.3 Object Transaction Monitors (OTMs)

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16.1 TP Monitor Basic

• History
• TP gt mainframe OLTP
• Client Server going to OLTP gt TP again

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16.1 TP Monitor Basics

• Three Key Things TP does
• Process management
• Transaction Management (ACID)
• C/S communications management
• How
• funneling pg 339
• load balancing, priorities (pg 343)
• synchronization

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What does a TP monitor do?

• Performs commit
• 3 way exchange between client, server, and TP mon
• State information in the messages
• Makes sure a receiver is present
• Provides routing to servers (load balancing)

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16.2 TP Monitor Benefits

• Development - lots of built in tools
• Firewalls for transactions
• High availability
• Load balancing
• Scalable
• MOM integration

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16.2 TP Monitor Benefits - continued

• Lower development cost (sometimes)
• Fewer SW licenses
• Can use multiple vendors
• Less hardware

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16.3 Object Transaction Monitors (OTMs)

• TP monitors are competing with distributed
  objects (ORBs) for 3 tier client server
  environments
• therefore
• TP monitor vendors moving to ORBs
• Called OTMs

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OTM Examples

• Microsoft Transaction Server (MTS)
• DCOM
• IBMs Component Broker
• CORBA
• BEAs Tuxedo M3
• CORBA
• Links to all on web site!!! Great background
  info.

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OTM Parts

• ORBs
• provide transaction communications
• TP monitors
• predictable
• keeps lots of objects from hitting the DB at one
  time

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Why buy a TP or OTM?

• Many companies try to build TP, but would never
  build a DBMS
• Therefore, 53 failure on in house TP
• TP and OTM offer infrastructure to your IS system

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When to use TP monitors

• gt 100 clients
• 3 or more physical servers
• 2 or more databases
• 5 or more TPC-C type transactions per minute
• TPC-C new order transactions while system
  handling 4 existing transactions with turnaround
  time of 5 seconds each

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Ch. 17 - TP Lite and TP Heavy

• TP was a mainframe concept
• Sybase moved into C/S market

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TP Lite

• DB transactions with stored procedures
• Often single vendor (Microsoft)
• Funneling
• TP monitor functions built into database

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TP Heavy

• Allows you to build FE separate from BE
• Includes such things as
• process management
• load balancing
• global transaction synchronization
• error recovery
• interfaces to multiple resource managers

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TP Heavy Advantages

• Global transaction control - ACID - pg 359
• Allows databases to be from multiple vendors
• Processes managed as server classes
• Cuts down on network traffic, but slower
• Performs better under heavy load
• www.tpc.org

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Ch 18. TP Monitor Players

• TP Monitor Trends
• becoming portable to all OS
• Allows control of multiple vendor clients
• Good developer tools becoming available
• Becoming object based - OTMs (MTS)

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18.3 Players

• IBM
• CICS, IMS, Encina, Websphere, Lotus Domino 5.0
• BEA
• Open Software www.bea.com
• Microsoft
• Microsoft Transaction Server (MTS)
• Really the first OTM

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BEAs Tuxedo
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Ch. 19 - GroupWare

• What is GroupWare?
• GroupWare components
• multimedia
• workflow
• email
• conferencing
• scheduling

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What is GroupWare??

• Groupware is software that supports the
  creation, flow, and tracking of non-structured
  information in direct support of collaborative
  group activity.
• text, pg. 388

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What is groupware? More details.

• Uses and manages unstructured data
• text, images, video, mail
• Organizes data into documents
• Provides ability to query, distribute and
  navigate document databases
• SQL with BLOBs may be able to do many groupware
  functions as databases become object driven!

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Groupware vs.TP Monitors

• Groupware does not have ACID properties
• no 2 phase commit to synchronize distributed
  changes
• Could be combined to complementary products

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19.3 Groupware components

• Multimedia document manager
• workflow manager
• email
• group conferencing
• group scheduling

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Multimedia documents

• Document is the basic unit of storage in
  groupware
• Lotus Notes created its own document database
  (not a structured SQL DB)
• E-image filing cabinet
• Gary Yorks technology with Emageon

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Workflow management

• River with ports (pg. 394)
• New workflow systems (pgs. 395-397)
• Workflow models
• routes
• rules
• roles
• Groupware must be able to support large and small
  workflow units

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Plexus Floware
www.plx.com/html/floware_scaleable_workflow.html
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Workflow

• Can support
• processes (loan applications)
• one time tasks (paper/book writing)
• Many theoretical models (pg. 399)
• Workflow products can change how companies
  internal processes work
• Therefore - need to take the big view when
  developing with and for workflow

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Workflow objects

• Workflow Management Coalition (WfMC) pg. 404 -
  405
• Workflow client API (WAPI)
• CORBA based Jflow - defines how distributed
  objects participate in workflow
• SWAP
• Complement to WfMC
• Developed by Netscape, Sun, and HP

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Other Groupware issues

• Email
• several protocols - SMTP, IAMP, POP3, LDAP
• several APIs - VIM, MAP, JavaMail
• many clients - Notes, Outlook, Eudora, ..
• Calendars, Scheduling, Conferencing
• Real time white boards (Netmeeting, Lotus
  Realtime Notes, Blackboard, WebCT)

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Ch. 20 - Groupware Players

• Lotus Notes / Domino (IBM)
• Microsoft (Exchange)
• Netscape/AOL Suitespot
• Novell Groupwise

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Groupware Trends

• Vendors embracing the Web - no duh!
• Becoming mission critical software packages
• Moving into
• C/S, NOS, telephony, and business management
• Developer tools are becoming friendly
• Becoming object oriented

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Groupware-today's drawbacks

• Still rely on single vendor operation
• Not great for
• OLTP
• heavy queries
• structured data
• multi-user updates with integrity (more like
  email with attachments)
• Not ACID

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Soapbox

• Target Locked Talent
• Linux/Unix vs NT
• Oracle vs SQL Server vs Access
• I will put Unix with Oracle against NT with SQL
  Server any day!
• Real issues
• People and money (not independent of one another)
• Technology is tools - not the reason we are in
  business