Control Transactions using PowerCenter

What will you learn today?
 Transaction processing using Informatica PowerCenter
 Mapping Tips & Tricks
 Hands-on:
i. Configuring Commit Points
ii. Mapping Tips & Tricks
www.edureka.co/informatica

Transaction Processing: Overview
Database Transactions
Database transaction is a set of SQL queries which forms one logical task
Either all or None
Commit and Rollback
To ensure integrity of transactions, database system must follow ACID properties
Atomic
Consistent
Isolation
Durable
Withdrawal of Money via ATM
1. Verify Account details/PIN number
2. Accept Withdrawal request
3. Check Balance
4. Update Balance
5. Dispense Money

Transaction Control in PowerCenter
A Transaction is a set of rows bound by commit or rollback rows, the transaction boundaries.
Rows which are not bound by any transaction boundary are called Open Transactions.
Product ID Customer Name
1 Timothy
1 Richard
1 Larry
2 Bill
2 Steve
NULL Laura
1 Timothy
1 Richard
1 Larry Product ID Customer Name
2 Bill
2 Steve
NULL Laura

Transaction Control: Why?
Monthly data to be committed to target as separate transactions
Reader Transformation Writer
Writer Buffer Block
Reader Buffer Block Transformation Buffer Block
Monthly data
COMMIT
Until the data is committed in the database,
PowerCenter server holds all the uncommitted
data in the DTM buffer blocks.
Recovery
Session statistics in Session log

Transaction Control: How?
PowerCenter lets you define transactions that the Integration Service uses when it processes transformations and
when it commits and rolls back data at a target.
Transaction boundaries originate from transaction control points. A transaction control point is a transformation that
defines or redefines the transaction boundary.
Session properties
Commit Interval
Commit Interval Type
Commit at end of file
Roll back at End of file
Commit Point
Commit point is the point at which we commit data to the target table.
Is a factor of
Commit Interval ( For example: 10000 rows)
Buffer Block Size
Commit Interval Type( Source based, Target based, User defined)

Commit Point
Commit point is the point at which we commit data to the target
table.
It is a factor of
Commit Interval ( For example: 10000 rows)
Buffer Block Size
Commit Interval Type( Source based, Target based, User
defined)

Source Based Commit
Source-based commit.
Number of source rows
Commit row is generated from active sources at every commit interval.
Commit occurs at configured commit interval.
Source
Source
Qualifier
Target
Total Source Records : 3300 rows
Source Based Commit: 1000 rows
Open Transaction : 300 rows

If the IS identifies a target that does not have a commit source, it switches to target-based commits for that target only
Switching to Target-Based Commits
The Integration Service writes the name of the transformation used for source-based
commit intervals into the session log. When the Integration Service switches to target-
based commit, it writes a message in the session log.
» Target receives data from XML Source Qualifier & you connect multiple output
groups from the XSQ
» Target receives data from any active source with multiple output groups such as a
Custom Transformation not configured to generate transactions
Integration Service uses target-based commit
when loading to the targets T_STORE and
T_PRODUCT
The Integration Service uses source-based
commit when loading to T_YTD_SALES.

TLOG – TCU – TCG

The Session generates a commit row at the commit source at every commit interval.
The Session writes the name of each transformation used as a commit source into the session log:
Session Log: “Source-based commit interval based on TRANSFORMATION_NAME”
Source-Based Commit: Session Log

Target-Based Commits
Target-Based Commits
During a target-based commit session, the Integration Service commits rows based on the number of target rows.
Target-based commit default is 10,000 rows
The commit point depends on the following factors:
» Commit interval. The number of rows you want to use as a basis for commits. Configure the target commit
interval in the session properties.
» Writer wait timeout. The amount of time the writer waits before it issues a commit. Configure the writer wait
timeout in the Integration Service setup.
» Buffer blocks. Blocks of memory that hold rows of data during a session. You can configure the buffer block
size in the session properties, but you cannot configure the number of rows the block holds.

Rollback Transaction on Errors
Rollback Transaction on Errors
Available for both Target-Based & Source-Based Commits
When Integration Service encounters a non-fatal writer error:
» It rolls back transaction at the next commit point
» It does not change the commit point

User-Defined Commits
User-Defined Commits(Data Driven)
During a user-defined commit session, the Integration Service commits and rolls back transactions based on a
row or set of rows that pass through a Transaction Control transformation.
The Integration Service evaluates the transaction control expression for each row that enters the transformation.
The return value of the transaction control expression defines the commit or rollback point.
You can choose to commit at end of file or to roll back that open transaction
Two Settings
Mapping – Use the Transaction Control Transformation to define the Transaction boundary
Session – Set the Commit Interval Type to User Defined Commit.

Transaction Control Transformation
Transformation tab. You can rename the transformation and add a description on the Transformation tab.
Ports tab. You can add input/output ports to a Transaction Control transformation.
Properties tab. You can define the transaction control expression, which flags transactions for commit, roll back, or no action.
Metadata Extensions tab. You can extend the metadata stored in the repository by associating information with the Transaction
Control transformation.

Transaction Control Actions
Transaction Control Actions

Transaction Control Transformation
Session Properties Used with TC
Session Property Default Description
Commit Type User defined
In a mapping with effective Transaction Control
Transformations, the session defaults to user-defined
commits. The Integration Service commits data based
upon the transaction control expression.
Commit on
End of File
Enabled
If enabled, the Integration Service commits data at the
end of the file. Clear this option if it is desired to have
the Integration Service roll back open transactions.
This option may also be used with source-based commit
sessions.
Rollback Transactions
on Errors
Commit
If the Integration Service encounters a non-fatal error,
the user may choose to roll back the transaction at the
next commit point.
This option may also be used with source-based commit
sessions. When this option is enabled for a source based
commit session, the Integration Service rolls back at writer errors.
However, It does not roll back when it encounters reader or DTM
errors.

Hands-On
 Configuring the Commit Points
 Mapping Tips & Tricks

Control Transactions using PowerCenter

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