informatica faq



informatica faq..

Answer / honney

What r the methods for creating reusable transforamtions?

Total Answers and Comments: 2

Two methods
1.Design it in the transformation developer.
2.Promote a standard transformation from the mapping designer.After U add
a transformation to the mapping , U can promote it to the status of
reusable transformation.
Once U promote a standard transformation to reusable status,U can demote
it to a standard transformation at any time.
If u change the properties of a reusable transformation in mapping,U can
revert it to the original reusable transformation properties by clicking
the revert button.



RE: What r the methods for creating reusable transfora...
________________________________________
You can design using 2 methods
1. using transformation developer
2. create normal one and promote it to reusable
What r the unsupported repository objects for a mapplet?

Total Answers and Comments: 1

COBOL source definition
Joiner transformations
Normalizer transformations
Non reusable sequence generator transformations.
Pre or post session stored procedures
Target defintions
Power mart 3.5 style Look Up functions
XML source definitions
IBM MQ source definitions

• Source definitions. Definitions of database objects (tables, views,
synonyms) or files that provide source data.

• Target definitions. Definitions of database objects or files that
contain the target data.

• Multi-dimensional metadata. Target definitions that are configured as
cubes and dimensions.

• Mappings. A set of source and target definitions along with
transformations containing business logic that you build into the
transformation. These are the instructions that the Informatica Server
uses to transform and move data
.
• Reusable transformations. Transformations that you can use in multiple
mappings.

• Mapplets. A set of transformations that you can use in multiple
mappings.

• Sessions and workflows. Sessions and workflows store information about
how and when the Informatica Server moves data. A workflow is a set of
instructions that describes how and when to run tasks related to
extracting, transforming, and loading data. A session is a type of task
that you can put in a workflow. Each session corresponds to a single
mapping.



Maping parameter represents a constant value that U can define before
running a session.A mapping parameter retains the same value throughout
the entire session.
When u use the maping parameter ,U declare and use the parameter in a
maping or maplet.Then define the value of parameter in a parameter file
for the session.
Unlike a mapping parameter,a maping variable represents a value that can
change throughout the session.The informatica server saves the value of
maping variable to the repository at the end of session run and uses that
value next time U run the session.

RE: mapping varibles
________________________________________
Please refer to the documentation for more understanding.
Mapping variables have two identities:
Start value and Current value
Start value = Current value ( when the session starts the execution of the
undelying mapping)
Start value <> Current value ( while the session is in progress and the
variable value changes in one ore more occasions)
Current value at the end of the session is nothing but the start value for
the subsequent run of the same session.

Can U use the maping parameters or variables created in one maping into
another maping?

NO.
We can use mapping parameters or variables in any transformation of the
same maping or mapplet in which U have created maping parameters or
variables

How can U improve session performance in aggregator transformation?

use sorted input:
1. use a sorter before the aggregator
2. donot forget to check the option on the aggregator that tell the
aggregator that the input is sorted on the same keys as group by.
the key order is also very important.
What is aggregate cache in aggregator transforamtion?

When you run a workflow that uses an Aggregator transformation, the
Informatica Server creates index and data caches in memory to process the
transformation. If the Informatica Server requires more space, it stores
overflow values in cache files.

What r the diffrence between joiner transformation and source qualifier
transformation?

U can join hetrogenious data sources in joiner transformation which we can
not achieve in source qualifier transformation.
U need matching keys to join two relational sources in source qualifier
transformation.Where as u doesn’t need matching keys to join two sources.
Two relational sources should come from same datasource in
sourcequalifier.U can join relatinal sources which r coming from diffrent
sources also.

Source qualifier – Homogeneous source
Joiner – Heterogeneous source

In which condtions we can not use joiner transformation(Limitaions of
joiner transformation)?

Both pipelines begin with the same original data source.
Both input pipelines originate from the same Source Qualifier
transformation.
Both input pipelines originate from the same Normalizer transformation.
Both input pipelines originate from the same Joiner transformation.
Either input pipelines contains an Update Strategy transformation.
Either input pipelines contains a connected or unconnected Sequence
Generator transformation.

This is no longer valid in version 7.2
Now we can use a joiner even if the data is coming from the same source.
SK
what r the settiings that u use to cofigure the joiner transformation?

• Master and detail source
• Type of join
• Condition of the join
the Joiner transformation supports the following join types, which you set
in the Properties tab:
• Normal (Default)
• Master Outer
• Detail Outer
• Full Outer
What r the join types in joiner transformation?
Normal (Default) -- only matching rows from both master and detail
Master outer -- all detail rows and only matching rows from master
Detail outer -- all master rows and only matching rows from detail
Full outer -- all rows from both master and detail ( matching or non
matching)

What r the joiner caches?
Specifies the directory used to cache master records and the index to
these records. By default, the cached files are created in a directory
specified by the server variable $PMCacheDir. If you override the
directory, make sure the directory exists and contains enough disk space
for the cache files. The directory can be a mapped or mounted drive.

what is the look up transformation?
Use lookup transformation in u’r mapping to lookup data in a relational
table,view,synonym.
Informatica server queries the look up table based on the lookup ports in
the transformation.It compares the lookup transformation port values to
lookup table column values based on the look up condition.
A lookup is a simple, single-level reference structure with no
parent/child relationships. Use a lookup when you have a set of reference
members that you do not need to organize hierarchically.
Why use the lookup transformation ?
To perform the following tasks.
Get a related value. For example, if your source table includes employee
ID, but you want to include the employee name in your target table to make
your summary data easier to read.
Perform a calculation. Many normalized tables include values used in a
calculation, such as gross sales per invoice or sales tax, but not the
calculated value (such as net sales).
Update slowly changing dimension tables. You can use a Lookup
transformation to determine whether records already exist in the target.
What r the types of lookup?
1. Connected lookup
2. Unconnected lookup
1. Persistent cache
2. Re-cache from database
3. Static cache
4. Dynamic cache
5. Shared cache
Differences between connected and unconnected lookup?
Connected lookup Unconnected lookup
Receives input values diectly from the pipe line. Receives input
values from the result of a lkp expression in a another transformation.
U can use a dynamic or static cache U can use a static cache.
Cache includes all lookup columns used in the maping Cache includes all
lookup out put ports in the lookup condition and the lookup/return port.
Support user defined default values Does not support user defiend
default values
what is meant by lookup caches?

The informatica server builds a cache in memory when it processes the
first row af a data in a cached look up transformation.It allocates memory
for the cache based on the amount u configure in the transformation or
session properties.The informatica server stores condition values in the
index cache and output values in the data cache.
What r the types of lookup caches?
Persistent cache: U can save the lookup cache files and reuse them the
next time the informatica server processes a lookup transformation
configured to use the cache.

Recache from database: If the persistent cache is not synchronized with he
lookup table,U can configure the lookup transformation to rebuild the
lookup cache.

Static cache: U can configure a static or readonly cache for only lookup
table.By default informatica server creates a static cache.It caches the
lookup table and lookup values in the cache for each row that comes into
the transformation.when the lookup condition is true,the informatica
server does not update the cache while it prosesses the lookup
transformation.

Dynamic cache: If u want to cache the target table and insert new rows
into cache and the target,u can create a look up transformation to use
dynamic cache.The informatica server dynamically inerts data to the target
table.

shared cache: U can share the lookup cache between multiple transactions.U
can share unnamed cache between transformations inthe same maping.
Difference between static cache and dynamic cache

Static cache Dynamic cache
U can not insert or update the cache U can insert rows into the cache
as u pass to the target
The informatic server returns a value from the lookup table or cache when
the condition is true.When the condition is not true, informatica server
returns the default value for connected transformations and null for
unconnected transformations. The informatic server inserts rows into
cache when the condition is false.This indicates that the the row is not
in the cache or target table. U can pass these rows to the target table
120. Which transformation should we use to normalize the COBOL and
relational sources?
Normalizer Transformation.
When U drag the COBOL source in to the mapping Designer workspace,the
normalizer transformation automatically appears,creating input and output
ports for every column in the source.
121. How the informatica server sorts the string values in
Ranktransformation?
When the informatica server runs in the ASCII data movement mode it sorts
session data using Binary sortorder.If U configure the seeion to use a
binary sort order,the informatica server caluculates the binary value of
each string and returns the specified number of rows with the higest
binary values for the string.
When Informatica Server runs in UNICODE data movement mode ,then it uses
the sort order configured in session properties
122. What r the rank caches?
During the session ,the informatica server compares an inout row with rows
in the datacache.If the input row out-ranks a stored row,the informatica
server replaces the stored row with the input row.The informatica server
stores group information in an index cache and row data in a data cache.
123. What is the Rankindex in Ranktransformation?
The Designer automatically creates a RANKINDEX port for each Rank
transformation. The Informatica Server uses the Rank Index port to store
the ranking position for each record in a group. For example, if you
create a Rank transformation that ranks the top 5 salespersons for each
quarter, the rank index numbers the salespeople from 1 to 5:
Based on which port you want generate Rank is known as rank port, the
generated values are known as rank index.
124. What is the Router transformation?
A Router transformation is similar to a Filter transformation because both
transformations allow you to use a condition to test data. A Filter
transformation tests data for one condition and drops the rows of data
that do not meet the condition. However, a Router transformation tests
data for one or more conditions and gives you the option to route rows of
data that do not meet any of the conditions to a default output group.

125. What r the types of groups in Router transformation

Input group Output group

The designer copies property information from the input ports of the input
group to create a set of output ports for each output group.
Two types of output groups
User defined groups
Default group
U can not modify or delete default groups.

126. Why we use stored procedure transformation

A Stored Procedure transformation is an important tool for populating and
maintaining databases. Database administrators create stored procedures to
automate time-consuming tasks that are too complicated for standard SQL
statements

127. What r the types of data that passes between informatica server
and stored procedure
3 types of data
Input/Out put parameters
Return Values
Status code
128. What is the status code?
Status code provides error handling for the informatica server during the
session.The stored procedure issues a status code that notifies whether or
not stored procedure completed sucessfully.This value can not seen by the
user.It only used by the informatica server to determine whether to
continue running the session or stop.
129.What is source qualifier transformation?
When U add a relational or a flat file source definition to a maping,U
need to connect it to
a source qualifer transformation.The source qualifier transformation
represnets the records
that the informatica server reads when it runs a session.
130. What r the tasks that source qualifier performs?
• Join data originating from the same source database. You can join two
or more tables with primary-foreign key relationships by linking the
sources to one Source Qualifier.
• Filter records when the Informatica Server reads source data. If you
include a filter condition, the Informatica Server adds a WHERE clause to
the default query.
• Specify an outer join rather than the default inner join. If you
include a user-defined join, the Informatica Server replaces the join
information specified by the metadata in the SQL query.
• Specify sorted ports. If you specify a number for sorted ports, the
Informatica Server adds an ORDER BY clause to the default SQL query.
• Select only distinct values from the source. If you choose Select
Distinct, the Informatica Server adds a SELECT DISTINCT statement to the
default SQL query.
• Create a custom query to issue a special SELECT statement for the
Informatica Server to read source data. For example, you might use a
custom query to perform aggregate calculations or execute a stored
procedure
131. What is the target load order?
U specify the target loadorder based on source qualifiers in a maping.If u
have the multiple
source qualifiers connected to the multiple targets,U can designatethe
order in which informatica
server loads data into the targets.
132. What is the default join that source qualifier provides?
INNER EQUI JOIN
133 What r the basic needs to join two sources in a source qualifier?
Two sources should have primary and Foreign key relation ships.
Two sources should have matching data types.
The both the table should have a common feild with same datatype.
Its not neccessary both should follow primary and foreign relationship. If
any relation ship exists that will help u in performance point of view.
134 what is update strategy transformation ?
This transformation is used to maintain the history data or just most
recent changes in to target
table.
135 Describe two levels in which update strategy transformation sets?
Within a session. When you configure a session, you can instruct the
Informatica Server to either treat all records in the same way (for
example, treat all records as inserts), or use instructions coded into the
session mapping to flag records for different database operations.

Within a mapping. Within a mapping, you use the Update Strategy
transformation to flag records for insert, delete, update, or reject.
136 What is the default source option for update stratgey
transformation?
Data driven.
137 What is Datadriven?
The informatica server follows instructions coded into update strategy
transformations with in the session maping determine how to flag records
for insert, update, delete or reject. If u do not choose data driven
option setting,the informatica server ignores all update strategy
transformations in the mapping

138. What r the options in the target session of update strategy
transsformatioin?
Insert
Delete
Update
Update as update
Update as insert
Update esle insert
Truncate table
139. What r the types of maping wizards that r to be provided in
Informatica?
The Designer provides two mapping wizards to help you create mappings
quickly and easily. Both wizards are designed to create mappings for
loading and maintaining star schemas, a series of dimensions related to a
central fact table.

Getting Started Wizard. Creates mappings to load static fact and dimension
tables, as well as slowly growing dimension tables.
Slowly Changing Dimensions Wizard. Creates mappings to load slowly
changing dimension tables based on the amount of historical dimension data
you want to keep and the method you choose to handle historical dimension
data.
140. What r the types of maping in Getting Started Wizard?
Simple Pass through maping :
Loads a static fact or dimension table by inserting all rows. Use this
mapping when you want to drop all existing data from your table before
loading new data.

Slowly Growing target :
Loads a slowly growing fact or dimension table by inserting new rows. Use
this mapping to load new data when existing data does not require updates.
141. What r the mapings that we use for slowly changing dimension
table?
Type1: Rows containing changes to existing dimensions are updated in the
target by overwriting the existing dimension. In the Type 1 Dimension
mapping, all rows contain current dimension data.
Use the Type 1 Dimension mapping to update a slowly changing dimension
table when you do not need to keep any previous versions of dimensions in
the table.

Type 2: The Type 2 Dimension Data mapping inserts both new and changed
dimensions into the target. Changes are tracked in the target table by
versioning the primary key and creating a version number for each
dimension in the table.
Use the Type 2 Dimension/Version Data mapping to update a slowly changing
dimension table when you want to keep a full history of dimension data in
the table. Version numbers and versioned primary keys track the order of
changes to each dimension.

Type 3: The Type 3 Dimension mapping filters source rows based on user-
defined comparisons and inserts only those found to be new dimensions to
the target. Rows containing changes to existing dimensions are updated in
the target. When updating an existing dimension, the Informatica Server
saves existing data in different columns of the same row and replaces the
existing data with the updates
142. What r the different types of Type2 dimension maping?
Type2 Dimension/Version Data Maping: In this maping the updated dimension
in the source will gets inserted in target along with a new version
number.And newly added dimension
in source will inserted into target with a primary key.

Type2 Dimension/Flag current Maping: This maping is also used for slowly
changing dimensions.In addition it creates a flag value for changed or new
dimension.
Flag indiactes the dimension is new or newlyupdated.Recent dimensions will
gets saved with cuurent flag value 1. And updated dimensions r saved with
the value 0.

Type2 Dimension/Effective Date Range Maping: This is also one flavour of
Type2 maping used for slowly changing dimensions.This maping also inserts
both new and changed dimensions in to the target.And changes r tracked by
the effective date range for each version of each dimension.
143. How can u recognise whether or not the newly added rows in the
source r gets insert in the target ?
In the Type2 maping we have three options to recognise the newly added
rows
Version number
Flagvalue
Effective date Range
144. What r two types of processes that informatica runs the session?
Load manager Process: Starts the session, creates the DTM process, and
sends post-session email when the session completes.
The DTM process. Creates threads to initialize the session, read, write,
and transform data, and handle pre- and post-session operations
145. What r the new features of the server manager in the informatica
5.0?
U can use command line arguments for a session or batch.This allows U to
change the values of session parameters,and mapping parameters and maping
variables.

Parallel data processing: This feature is available for powercenter
only.If we use the informatica server on a SMP system,U can use multiple
CPU’s to process a session concurently.

Process session data using threads: Informatica server runs the session in
two processes.Explained in previous question.
146. Can u generate reports in Informatcia?
Yes. By using Metadata reporter we can generate reports
in informatica.
147 What is metadata reporter?
It is a web based application that enables you to run reports againist
repository metadata.
With a meta data reporter,u can access information about U’r repository
with out having knowledge of sql,transformation language or underlying
tables in the repository.
148. Define maping and sessions?
Maping: It is a set of source and target definitions linked by
transformation objects that define the rules for transformation.
Session : It is a set of instructions that describe how and when to move
data from source to targets.
149. Which tool U use to create and manage sessions and batches and to
monitor and stop the informatica server
Informatica server manager
150. Why we use partitioning the session in informatica?
Partitioning achieves the session performance by reducing the time period
of reading the source and loading the data into target.

Performance can be improved by processing data in parallel in a single
session by creating multiple partitions of the pipeline.
Informatica server can achieve high performance by partitioning the
pipleline and performing the extract , transformation, and load for each
partition in parallel.
151. To achieve the session partition what r the necessary tasks u have
to do?
Configure the session to partition source data.

Install the informatica server on a machine with multiple CPU’s.
152. How the informatica server increases the session performance
through partitioning the source?
For a relational sources informatica server creates multiple connections
for each parttion of a single source and extracts seperate range of data
for each connection.Informatica server reads multiple partitions of a
single source concurently.Similarly for loading also informatica server
creates multiple connections to the target and loads partitions of data
concurently.

For XML and file sources,informatica server reads multiple files
concurently.For loading the data informatica server creates a seperate
file for each partition(of a source file).U can choose to merge the
targets.
153. Why u use repository connectivity?
When u edit,schedule the sesion each time,informatica server directly
communicates the repository to check whether or not the session and users
r valid.All the metadata of sessions and mappings will be stored in
repository.
154. What is DTM process?
After the loadmanger performs validations for session,it creates the DTM
process.DTM is to create and manage the threads that carry out the session
tasks.I creates the master thread.Master thread creates and manges all the
other threads.
155. What r the different threads in DTM process?
Master thread: Creates and manages all other threads

Maping thread: One maping thread will be creates for each session.Fectchs
session and maping information.

Pre and post session threads: This will be created to perform pre and post
session operations.

Reader thread: One thread will be created for each partition of a
source.It reads data from source.

Writer thread: It will be created to load data to the target.

Transformation thread: It will be created to tranform data.
156. What r the data movement modes in informatcia?
Datamovement modes determines how informatcia server handles the charector
data.U choose the datamovement in the informatica server configuration
settings.Two types of datamovement modes avialable in informatica.

ASCII mode
Uni code mode.
157. What r the out put files that the informatica server creates
during the session running?
Informatica server log: Informatica server(on unix) creates a log for all
status and error messages(default name: pm.server.log).It also creates an
error log for error messages.These files will be created in informatica
home directory.

Session log file: Informatica server creates session log file for each
session.It writes information about session into log files such as
initialization process,creation of sql commands for reader and writer
threads,errors encountered and load summary.The amount of detail in
session log file depends on the tracing level that u set.

Session detail file: This file contains load statistics for each targets
in mapping.Session detail include information such as table name,number of
rows written or rejected.U can view this file by double clicking on the
session in monitor window

Performance detail file: This file contains information known as session
performance details which helps U where performance can be improved.To
genarate this file select the performance detail option in the session
property sheet.

Reject file: This file contains the rows of data that the writer does
notwrite to targets.

Control file: Informatica server creates control file and a target file
when U run a session that uses the external loader.The control file
contains the information about the target flat file such as data format
and loading instructios for the external loader.

Post session email: Post session email allows U to automatically
communicate information about a session run to designated recipents.U can
create two different messages.One if the session completed sucessfully the
other if the session fails.

Indicator file: If u use the flat file as a target,U can configure the
informatica server to create indicator file.For each target row,the
indicator file contains a number to indicate whether the row was marked
for insert,update,delete or reject.

output file: If session writes to a target file,the informatica server
creates the target file based on file prpoerties entered in the session
property sheet.

Cache files: When the informatica server creates memory cache it also
creates cache files.For the following circumstances informatica server
creates index and datacache files.

Aggreagtor transformation
Joiner transformation
Rank transformation
Lookup transformation
158. In which circumstances that informatica server creates Reject
files?
When it encounters the DD_Reject in update strategy transformation.
Violates database constraint
Filed in the rows was truncated or overflowed.
159. What is polling?
It displays the updated information about the session in the monitor
window. The monitor window displays the status of each session when U poll
the informatica server
160. Can u copy the session to a different folder or repository?
Yes. By using copy session wizard u can copy a session in a different
folder or repository.But that
target folder or repository should consists of mapping of that session.
If target folder or repository is not having the maping of copying
session ,
u should have to copy that maping first before u copy the session
161. What is batch and describe about types of batches?
Grouping of session is known as batch.Batches r two types
Sequential: Runs sessions one after the other
Concurrent: Runs session at same time.

If u have sessions with source-target dependencies u have to go for
sequential batch to start the
sessions one after another.If u have several independent sessions u can
use concurrent batches.
Whch runs all the sessions at the same time.
162. Can u copy the batches?
NO
163. How many number of sessions that u can create in a batch?
Any number of sessions
164. When the informatica server marks that a batch is failed?
If one of session is configured to "run if previous completes" and that
previous session fails.
165. What is a command that used to run a batch?
pmcmd is used to start a batch.
166. What r the different options used to configure the sequential
batches?
Two options

Run the session only if previous session completes sucessfully. Always
runs the session.
167. In a sequential batch can u run the session if previous session
fails?
Yes.By setting the option always runs the session.
168. Can u start a batches with in a batch?
U can not. If u want to start batch that resides in a batch,create a new
independent batch and copy the necessary sessions into the new batch.
169. Can u start a session inside a batch idividually?
We can start our required session only in case of sequential batch.in case
of concurrent batch
we cant do like this.
170 How can u stop a batch?
By using server manager or pmcmd
171. What r the session parameters?
Session parameters r like maping parameters,represent values U might want
to change between
sessions such as database connections or source files.

Server manager also allows U to create userdefined session
parameters.Following r user defined
session parameters.
Database connections
Source file names: use this parameter when u want to change the name or
location of
session source file between session runs
Target file name : Use this parameter when u want to change the name or
location of
session target file between session runs.
Reject file name : Use this parameter when u want to change the name or
location of
session reject files between session runs.
172. What is parameter file?
Parameter file is to define the values for parameters and variables used
in a session.A parameter
file is a file created by text editor such as word pad or notepad.
U can define the following values in parameter file
Maping parameters
Maping variables
session parameters
173. How can u access the remote source into U’r session?
Relational source: To acess relational source which is situated in a
remote place ,u need to
configure database connection to the datasource.

FileSource : To access the remote source file U must configure the FTP
connection to the
host machine before u create the session.

Hetrogenous : When U’r maping contains more than one source type,the
server manager creates
a hetrogenous session that displays source options for all types.
174. What is difference between partioning of relatonal target and
partitioning of file targets?
If u parttion a session with a relational target informatica server
creates multiple connections
to the target database to write target data concurently.If u partition a
session with a file target
the informatica server creates one target file for each partition.U can
configure session properties
to merge these target files.
175. what r the transformations that restricts the partitioning of
sessions?
Advanced External procedure tranformation and External procedure
transformation: This
transformation contains a check box on the properties tab to allow
partitioning.

Aggregator Transformation: If u use sorted ports u can not parttion the
assosiated source

Joiner Transformation : U can not partition the master source for a joiner
transformation

Normalizer Transformation

XML targets.
176. Performance tuning in Informatica?
The goal of performance tuning is optimize session performance so sessions
run during the available load window for the Informatica Server.Increase
the session performance by following.

The performance of the Informatica Server is related to network
connections. Data generally moves across a network at less than 1 MB per
second, whereas a local disk moves data five to twenty times faster. Thus
network connections ofteny affect on session performance.So aviod netwrok
connections.

Flat files: If u’r flat files stored on a machine other than the
informatca server, move those files to the machine that consists of
informatica server.
Relational datasources: Minimize the connections to sources ,targets and
informatica server to
improve session performance.Moving target database into server system may
improve session
performance.
Staging areas: If u use staging areas u force informatica server to
perform multiple datapasses.
Removing of staging areas may improve session performance.

U can run the multiple informatica servers againist the same
repository.Distibuting the session load to multiple informatica servers
may improve session performance.

Run the informatica server in ASCII datamovement mode improves the session
performance.Because ASCII datamovement mode stores a character value in
one byte.Unicode mode takes 2 bytes to store a character.

If a session joins multiple source tables in one Source Qualifier,
optimizing the query may improve performance. Also, single table select
statements with an ORDER BY or GROUP BY clause may benefit from
optimization such as adding indexes.

We can improve the session performance by configuring the network packet
size,which allows
data to cross the network at one time.To do this go to server
manger ,choose server configure database connections.

If u r target consists key constraints and indexes u slow the loading of
data.To improve the session performance in this case drop constraints and
indexes before u run the session and rebuild them after completion of
session.

Running a parallel sessions by using concurrent batches will also reduce
the time of loading the
data.So concurent batches may also increase the session performance.

Partittionig the session improves the session performance by creating
multiple connections to sources and targets and loads data in paralel pipe
lines.

In some cases if a session contains a aggregator transformation ,u can use
incremental aggregation to improve session performance.

Aviod transformation errors to improve the session performance.

If the sessioin containd lookup transformation u can improve the session
performance by enabling the look up cache.

If U’r session contains filter transformation ,create that filter
transformation nearer to the sources
or u can use filter condition in source qualifier.

Aggreagator,Rank and joiner transformation may oftenly decrease the
session performance .Because they must group data before processing it.To
improve session performance in this case use sorted ports option.
177. What is difference between maplet and reusable transformation?
Maplet consists of set of transformations that is reusable.A reusable
transformation is a
single transformation that can be reusable.

If u create a variables or parameters in maplet that can not be used in
another maping or maplet.Unlike the variables that r created in a reusable
transformation can be usefull in any other maping or maplet.

We can not include source definitions in reusable transformations.But we
can add sources to a maplet.

Whole transformation logic will be hided in case of maplet.But it is
transparent in case of reusable transformation.

We cant use COBOL source qualifier,joiner,normalizer transformations in
maplet.Where as we can make them as a reusable transformations.
178. Define informatica repository?
The Informatica repository is a relational database that stores
information, or metadata, used by the Informatica Server and Client tools.
Metadata can include information such as mappings describing how to
transform source data, sessions indicating when you want the Informatica
Server to perform the transformations, and connect strings for sources and
targets.

The repository also stores administrative information such as usernames
and passwords, permissions and privileges, and product version.

Use repository manager to create the repository.The Repository Manager
connects to the repository database and runs the code needed to create the
repository tables.Thsea tables
stores metadata in specific format the informatica server,client tools use.
179. What r the types of metadata that stores in repository?
Following r the types of metadata that stores in the repository

Database connections
Global objects
Mappings
Mapplets
Multidimensional metadata
Reusable transformations
Sessions and batches
Short cuts
Source definitions
Target defintions
Transformations
180. What is power center repository?
The PowerCenter repository allows you to share metadata across
repositories to create a data mart domain. In a data mart domain, you can
create a single global repository to store metadata used across an
enterprise, and a number of local repositories to share the global
metadata as needed.
181. How can u work with remote database in informatica?did u work
directly by using remote connections?
To work with remote datasource u need to connect it with remote
connections.But it is not
preferable to work with that remote source directly by using remote
connections .Instead u bring that source into U r local machine where
informatica server resides.If u work directly with remote source the
session performance will decreases by passing less amount of data across
the network in a particular time.
182. What r the new features in Informatica 5.0?
U can Debug U’r maping in maping designer
U can view the work space over the entire screen
The designer displays a new icon for a invalid mapings in the navigator
window
U can use a dynamic lookup cache in a lokup transformation
Create maping parameters or maping variables in a maping or maplet to make
mapings more
flexible
U can export objects into repository and import objects from
repository.when u export a repository object,the designer or server
manager creates an XML file to describe the repository metadata.
The designer allows u to use Router transformation to test data for
multiple conditions.Router transformation allows u route groups of data to
transformation or target.
U can use XML data as a source or target.

Server Enahancements:

U can use the command line program pmcmd to specify a parameter file to
run sessions or batches.This allows you to change the values of session
parameters, and mapping parameters and variables at runtime.

If you run the Informatica Server on a symmetric multi-processing system,
you can use multiple CPUs to process a session concurrently. You configure
partitions in the session properties based on source qualifiers. The
Informatica Server reads, transforms, and writes partitions of data in
parallel for a single session. This is avialable for Power center only.

Informatica server creates two processes like loadmanager process,DTM
process to run the sessions.

Metadata Reporter: It is a web based application which is used to run
reports againist repository metadata.

U can copy the session across the folders and reposotories using the copy
session wizard in the informatica server manager

With new email variables, you can configure post-session email to include
information, such as the mapping used during the session
183. what is incremantal aggregation?
When using incremental aggregation, you apply captured changes in the
source to aggregate calculations in a session. If the source changes only
incrementally and you can capture changes, you can configure the session
to process only those changes. This allows the Informatica Server to
update your target incrementally, rather than forcing it to process the
entire source and recalculate the same calculations each time you run the
session
184 What r the scheduling options to run a sesion?
U can shedule a session to run at a given time or intervel,or u can
manually run the session.

Different options of scheduling

Run only on demand: server runs the session only when user starts session
explicitly
Run once: Informatica server runs the session only once at a specified
date and time.
Run every: Informatica server runs the session at regular intervels as u
configured.
Customized repeat: Informatica server runs the session at the dats and
times secified in the repeat dialog box.
185. What is tracing level and what r the types of tracing level?
Tracing level represents the amount of information that informatcia server
writes in a log file.
Types of tracing level
Normal
Verbose
Verbose init
Verbose data
186. What is difference between stored procedure transformation and
external procedure transformation?
In case of storedprocedure transformation procedure will be compiled and
executed in a relational data source.U need data base connection to import
the stored procedure in to u’r maping.Where as in external procedure
transformation procedure or function will be executed out side of data
source.Ie u need to make it as a DLL to access in u r maping.No need to
have data base connection in case of external procedure transformation.
187. Explain about Recovering sessions?
If you stop a session or if an error causes a session to stop, refer to
the session and error logs to determine the cause of failure. Correct the
errors, and then complete the session. The method you use to complete the
session depends on the properties of the mapping, session, and Informatica
Server configuration.
Use one of the following methods to complete the session:
• Run the session again if the Informatica Server has not issued a commit.
• Truncate the target tables and run the session again if the session is
not recoverable.
• Consider performing recovery if the Informatica Server has issued at
least one commit.
188 If a session fails after loading of 10,000 records in to the
target.How can u load the records from 10001 th record when u run the
session next time?
As explained above informatcia server has 3 methods to recovering the
sessions.Use performing recovery to load the records from where the
session fails.
189 Explain about perform recovery?
When the Informatica Server starts a recovery session, it reads the
OPB_SRVR_RECOVERY table and notes the row ID of the last row committed to
the target database. The Informatica Server then reads all sources again
and starts processing from the next row ID. For example, if the
Informatica Server commits 10,000 rows before the session fails, when you
run recovery, the Informatica Server bypasses the rows up to 10,000 and
starts loading with row 10,001.
By default, Perform Recovery is disabled in the Informatica Server setup.
You must enable Recovery in the Informatica Server setup before you run a
session so the Informatica Server can create and/or write entries in the
OPB_SRVR_RECOVERY table.
190. How to recover the standalone session?
A standalone session is a session that is not nested in a batch. If a
standalone session fails, you can run recovery using a menu command or
pmcmd. These options are not available for batched sessions.

To recover sessions using the menu:
1. In the Server Manager, highlight the session you want to recover.
2. Select Server Requests-Stop from the menu.
3. With the failed session highlighted, select Server Requests-Start
Session in Recovery Mode from the menu.

To recover sessions using pmcmd:
1.From the command line, stop the session.
2. From the command line, start recovery.
191. How can u recover the session in sequential batches?
If you configure a session in a sequential batch to stop on failure, you
can run recovery starting with the failed session. The Informatica Server
completes the session and then runs the rest of the batch. Use the Perform
Recovery session property

To recover sessions in sequential batches configured to stop on failure:

1.In the Server Manager, open the session property sheet.
2.On the Log Files tab, select Perform Recovery, and click OK.
3.Run the session.
4.After the batch completes, open the session property sheet.
5.Clear Perform Recovery, and click OK.

If you do not clear Perform Recovery, the next time you run the session,
the Informatica Server attempts to recover the previous session.
If you do not configure a session in a sequential batch to stop on
failure, and the remaining sessions in the batch complete, recover the
failed session as a standalone session.
192 How to recover sessions in concurrent batches?
If multiple sessions in a concurrent batch fail, you might want to
truncate all targets and run the batch again. However, if a session in a
concurrent batch fails and the rest of the sessions complete successfully,
you can recover the session as a standalone session.
To recover a session in a concurrent batch:
1.Copy the failed session using Operations-Copy Session.
2.Drag the copied session outside the batch to be a standalone session.
3.Follow the steps to recover a standalone session.
4.Delete the standalone copy.
193. How can u complete unrcoverable sessions?
Under certain circumstances, when a session does not complete, you need to
truncate the target tables and run the session from the beginning. Run the
session from the beginning when the Informatica Server cannot run recovery
or when running recovery might result in inconsistent data.
194. What r the circumstances that infromatica server results an
unreciverable session?
The source qualifier transformation does not use sorted ports.
If u change the partition information after the initial session fails.
Perform recovery is disabled in the informatica server configuration.
If the sources or targets changes after initial session fails.
If the maping consists of sequence generator or normalizer transformation.
If a concuurent batche contains multiple failed sessions.
195. If i done any modifications for my table in back end does it
reflect in informatca warehouse or maping desginer or source analyzer?
NO. Informatica is not at all concern with back end data base.It displays
u all the information
that is to be stored in repository.If want to reflect back end changes to
informatica screens,
again u have to import from back end to informatica by valid
connection.And u have to replace the existing files with imported files.
196.After draging the ports of three sources(sql server,oracle,informix)
to a single source qualifier, can u map these three ports directly to
target?
NO.Unless and until u join those three ports in source qualifier u cannot
map them directly.
if u drag three hetrogenous sources and populated to target without any
join means you are entertaining Carteisn product. If you don't use join
means not only diffrent sources but homegeous sources are show same error.
If you are not interested to use joins at source qualifier level u can add
some joins sepratly.
197. What are Target Types on the Server?
Target Types are File, Relational and ERP.
Target types are relational,file and XML
198. What are Target Options on the Servers?
Target Options for File Target type are FTP File, Loader and MQ.
There are no target options for ERP target type
Target Options for Relational are Insert, Update (as Update), Update (as
Insert), Update (else Insert), Delete, and Truncate Table.

199. How do you identify existing rows of data in the target table
using lookup transformation?
Can identify existing rows of data using unconnected lookup transformation.
200. What are Aggregate transformation?
Aggregator transformation allows you to perform aggregate calculations,
such as averages and sums.
201. What are various types of Aggregation?
Various types of aggregation are SUM, AVG, COUNT, MAX, MIN, FIRST, LAST,
MEDIAN, PERCENTILE, STDDEV, and VARIANCE
202. What is Code Page Compatibility?
set of level properties that describe a specific aspect of a business,
used for analyzing the factual measures of one or more cubes, which use
that dimension. Egs. Geography, time, customer and product.
203. What is Code Page used for?
Code Page is used to identify characters that might be in different
languages. If you are importing Japanese data into mapping, u must select
the Japanese code page of source data.
204. what is a source qualifier?-
It represents all data queried from the source.
It is a transformation which represents the data Informatica server reads
from source
205. Why we use lookup transformations?
Lookup Transformations can access data from relational tables that are not
sources in mapping. With Lookup transformation, we can accomplish the
following tasks:
Get a related value-Get the Employee Name from Employee table based on the
Employee IDPerform Calculation.
Update slowly changing dimension tables - We can use unconnected lookup
transformation to determine whether the records already exist in the
target or not.
206. While importing the relational source defintion from database,what
are the meta data of source U import?
Source name
Database location
Column names
Datatypes
Key constraints
207.How many ways you can update a relational source defintion and what r
they?
Two ways
1. Edit the definition
2. Reimport the definition
208 . What is Data Transformation Manager?
After the load manager performs validations for the session, it creates
the DTM process. The DTM process is the second process associated with the
session run. The primary purpose of the DTM process is to create and
manage threads that carry out the session tasks.
• The DTM allocates process memory for the session and divide it into
buffers. This is also known as buffer memory. It creates the main thread,
which is called the master thread. The master thread creates and manages
all other threads.
• If we partition a session, the DTM creates a set of threads for each
partition to allow concurrent processing.. When Informatica server writes
messages to the session log it includes thread type and thread ID.
Following are the types of threads that DTM creates:
Master thread - Main thread of the DTM process. Creates and manages all
other threads.Mapping thread - One Thread to Each Session. Fetches Session
and Mapping Information.Pre and Post Session Thread-One Thread each to
Perform Pre and Post Session Operations.reader thread-One Thread for Each
Partition for Each Source Pipeline.WRITER THREAD-One Thread for Each
Partition if target exist in the source pipeline write to the
target.tRANSFORMATION THREAD - One or More Transformation Thread For Each
Partition.
209. What is Session and Batches?
Session - A Session Is A set of instructions that tells the Informatica
Server How And When To Move Data From Sources To Targets. After creating
the session, we can use either the server manager or the command line
program pmcmd to start or stop the session.Batches - It Provides A Way to
Group Sessions For Either Serial Or Parallel Execution By The Informatica
Server. There Are Two Types Of Batches :
Sequential - Run Session One after the Other.concurrent - Run Session At
The Same Time.
210. Why we use lookup transformations?
Lookup Transformations can access data from relational tables that are not
sources in mapping. With Lookup transformation, we can accomplish the
following tasks:
Get a related value-Get the Employee Name from Employee table based on the
Employee IDPerform Calculation.
Update slowly changing dimension tables - We can use unconnected lookup
transformation to determine whether the records already exist in the
target or not.





















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