1. While importing the
relational source definition from database, what are the metadata of source U
import?
Source name
Database location
Column names
Data types
Key constraints
2. How many ways U can
update a relational source definition and what r they?
Two ways
1. Edit the definition
2. Re import the definition
3. Where should U place
the flat file to import the flat file definition to the designer?
Place it in local folder
4. To provide support
for Mainframes source data, which files r used as a source definitions?
COBOL files
5. Which
transformation should u need while using the COBOL sources as source
definitions?
Normalizer
transformation which is used to normalize the data. Since COBOL sources r often
consists of Denormailzed data.
6. How can U create or
import flat file definition in to the warehouse designer?
U can not create or import flat file
definition in to warehouse designer directly. Instead U must analyze the file
in source analyzer, and then drag it into the warehouse designer. When u drags
the flat file source definition into warehouse designer workspace, the
warehouse designer creates a relational target definition not a file
definition. If u want to load to a file, configure the session to write to a
flat file. When the informatica server runs the session, it creates and loads
the flat file.
7. What is the
maplet?
Maplet
is a set of transformations that you build in the maplet designer and U can use
in multiple mappings.
8. What is a
transformation?
It
is a repository object that generates, modifies or passes data.
9. What r the designer
tools for creating transformations?
Mapping designer
Transformation developer
Mapplet designer
10. What r the active
and passive transformations?
An active transformation can change the number
of rows that pass through it. A passive transformation does not change the
number of rows that pass through it.
11. What r the
connected or unconnected transformations?
An unconnected transforamtion is not
connected to other transformations in the mapping.Connected transforamation is
connected to other transforamtions in the mapping.
12. How many ways u
create ports?
Two ways
1.Drag the port from another
transforamtion
2.Click the add buttion on the ports
tab.
14. What r the
reusable transforamtions?
Reusable transformations can be used in
multiple mappings.When u need to incorporate this transformation into maping,U add an instance of it to
maping.Later if U change the definition of the transformation ,all instances of
it inherit the changes.Since the instance of reusable transforamation is a
pointer to that transforamtion,U can change the transforamation in the
transformation developer,its instances automatically reflect these changes.This feature can save U great deal of
work.
15. What r the methods
for creating reusable transforamtions?
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.
16.What r the
unsupported repository objects for a mapplet?
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 defintions
17. What r the mapping
paramaters and maping variables?
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.
18. 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.
19.Can u use the maping parameters or variables created in one
maping into any other reusable transformation?
Yes.Because reusable tranformation is not
contained with any maplet or maping.
20.How can U improve
session performance in aggregator transformation?
Use
sorted input.
21.What is aggregate cache in aggregator
transforamtion?
The aggregator stores data in the
aggregate cache until it completes aggregate calculations.When u run a session
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.
22.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.
23.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.
24. What r the
settings that u use to configure the joiner transformation?
Master and detail source
Type of join
Condition of the join
25. What r the join
types in joiner transformation?
Normal (Default)
Master outer
Detail outer
Full outer
26.What r the joiner
caches?
When a Joiner transformation occurs in a
session, the Informatica Server reads all the records from the master source
and builds index and data caches based on the master rows.
After
building the caches, the Joiner transformations reads records from the detail
source and perform joins.
27. 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.
28.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.
29.What r the types of
lookup?
Connected
and unconnected
30.Differences between
connected and unconnected lookup?
Connected lookup
Unconnected lookup
Receives input values diectly from Receives input values
from the result of a
the pipe line. 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 Cache includes all lookup out
put ports in the
used in the mapping
lookup condition and the lookup/return port.
Support user defined default values Does not support user defiend
default values
31.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.
32. 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 read-only 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.
33. Difference between
static cache and dynamic cache
Static cache Dynamic
cache
U can not inert 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 informatic server inserts rows into cache
the
lookup table opr cache when the condition
when the condition is false.This indicates that
is
true.When the condition is not true,the the row is not in the cache or target table.
informatica
server returns the default value
U can pass these rows to the target table.
for connected transformations and null for
unconnected
transformations.
34. 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.
35.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.
36.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.
37.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:
38.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. However, a Filter
transformation tests data for one condition and drops the rows of data that do
not meet the condition. 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.
If you need to test the same input data based
on multiple conditions, use a Router Transformation in a mapping instead of
creating multiple Filter transformations to perform the same task.
39.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.
40.Why
we use stored procedure transformation?
For populating and maintaining data bases.
42.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.
43.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.
44. 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.
45.What
r the tasks that source qualifier performs?
Join data originating from same
source data base.
Filter records when the informatica server reads source data.
Specify an outer join rather than the default inner join specify sorted
records.
Select only distinct values from the source.
Creating custom query to issue a special SELECT statement for the
informatica server to read
source data.
46.
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.
47.What
is the default join that source qualifier provides?
Inner equi join.
48.
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.
49.what
is update strategy transformation ?
This transformation is used to maintain the history data or just most
recent changes in to target table.
50.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.
51.What
is the default source option for update stratgey transformation?
Data driven.
52.
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.
53.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
54.
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.
55. 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.
56. 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
57.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.
58.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
59. 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.
60. 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 processig: 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.
61. Can u generate reports in
Informatcia?
Yes. By using Metadata reporter we can generate reports in
informatica.
62.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.
63.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.
64.Which tool U use to create and
manage sessions and batches and to monitor and stop the informatica server?
Informatica server manager.
65.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.
66.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.
67.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.
68. 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.
69.What r the tasks that Loadmanger
process will do?
Manages the session and batch scheduling:
Whe u start the informatica server the load maneger launches and queries the
repository for a list of sessions configured
to run on the informatica server.When u configure the session the loadmanager
maintains list of list of sessions and session start times.When u sart a
session loadmanger fetches the session information from the repository to
perform the validations and verifications prior to starting DTM process.
Locking and
reading the session: When the informatica server starts a session lodamaager
locks the session from the repository.Locking prevents U starting the session
again and again.
Reading the
parameter file: If the session uses a parameter files,loadmanager reads the
parameter file and verifies that the session level parematers are declared in
the file
Verifies
permission and privelleges: When the sesson
starts load manger checks whether
or not the user have privelleges to run the session.
Creating
log files: Loadmanger creates logfile contains the status of session.
70. 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.
71. 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.
72.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.
73. 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
74.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.
75. 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
76. 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
77. 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.
78. Can u copy the
batches?
NO
79.How many number of
sessions that u can create in a batch?
Any
number of sessions.
80.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.
81. What is a command
that used to run a batch?
pmcmd
is used to start a batch.
82. 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.
83. In a sequential
batch can u run the session if previous session fails?
Yes.By setting the option always runs the
session.
84. 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.
85. 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.
86. How can u stop a
batch?
By
using server manager or pmcmd.
87. 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.
88. 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
89. 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.
90. 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.
91. 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.
92. 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.
92. 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.
93. 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.
94. 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
95. 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.
96. 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.
97. 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
98. 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.
99. 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.
100 .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
101. 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.
102. 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.
103. 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.
104. 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.
105. 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.
106. 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.
107. 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.
108. 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.
109. 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.
110. 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.
111. 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.
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