Download pdf - Informatica FAQs - Total 111 FAQs

7/31/2019 Informatica FAQs - Total 111 FAQs

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Informatica FAQ

Q1. While importing the relational source definition from database,what are the metadata of source you import?Ans:

Source name. Database location. Column names. Data types. Key constraints.

Q2. How many ways you can update a relational source definition andwhat are they?Ans:

Two ways1. Edit the definition2.

Re-import the definition

Q3. Where should you place the flat file to import the flat file definitionto the designer?Ans: Place it in local folder

Q4. To provide support for Mainframes source data, which files areused as a source definitions?Ans: COBOL files

Q5. Which transformation should you need while using the COBOLsources as source definitions?

Ans:Normalizer transformation which is used to normalize the data.

Since COBOL sources are oftenly consists of De-normalized data.

Q6. How can you create or import flat file definition in to thewarehouse designer?Ans:

You can not create or import flat file definition in to warehousedesigner directly. Instead you must analyze the file in sourceanalyzer, then drag it into the warehouse designer. When youdrag the flat file source definition into warehouse designer

workspace, the warehouse designer creates a relational targetdefinition not a file definition. If you want to load to a file,configure the session to write to a flat file. When the Informaticaserver runs the session, it creates and loads the flat file.

Q7. What is the mapplet?

Ans:Mapplet is a set of transformations that you build in the mappletdesigner and you can use in multiple mappings.


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Q8. What is a transformation?Ans:

It is a repository object that generates, modifies or passes data.

Q9. What are the designer tools for creating transformations?Ans:

Mapping designer Transformation developer Mapplet designer

Q10. What are the active and passive transformations?Ans:

An active transformation can change the number of rows thatpass through it. A passive transformation does not change thenumber of rows that pass through it.

Q11. What are the connected or unconnected transformations?Ans:

An unconnected transformation is not connected to othertransformations in the mapping. Connected transformation isconnected to other transformations in the mapping.

Q12. How many ways you create ports?Ans:

Two ways1. Drag the port from another transformation.2. Click the add button on the ports tab.

Q14. What are the reusable transformations?Ans:

Reusable transformations can be used in multiple mappings.When you need to incorporate this transformation into mapping,

you add an instance of it to mapping. Later if you change thedefinition of the transformation, all instances of it inherit thechanges. Since the instance of reusable transformation is apointer to that transformation, you can change thetransformation in the transformation developer, its instancesautomatically reflect these changes. This feature can save yougreat deal of work.

Q15. What are the methods for creating reusable transformations?Ans:

Two methods1. Design it in the transformation developer.2. Promote a standard transformation from the mappingdesigner. After you add a transformation to the mapping, youcan promote it to the status of reusable transformation.

Once you promote a standard transformation to reusablestatus, you can demote it to a standard transformation at anytime.


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If you change the properties of a reusable transformation inmapping, you can revert it to the original reusabletransformation properties by clicking the revert button.

Q16. What are the unsupported repository objects for a mapplet?Ans:

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

Q17. What are the mapping parameters and mapping variables?Ans:

Mapping parameter represents a constant value that you candefine before running a session. A mapping parameter retains thesame value throughout the entire session.When you use the mapping parameter, you declare and use theparameter in a mapping or mapplet. Then define the value ofparameter in a parameter file for the session.Unlike a mapping parameter, a mapping variable represents avalue that can change throughout the session. The Informaticaserver saves the value of mapping variable to the repository at theend of session run and uses that value next time you run thesession.

Q18. Can you use the mapping parameters or variables created in onemapping into another mapping?Ans:

NO, we can use mapping parameters or variables in anytransformation of the same mapping or mapplet in which youhave created mapping parameters or variables.

Q19. Can you use the mapping parameters or variables created in one

mapping into any other reusable transformation?Ans:

Yes, because reusable transformation is not contained with any

mapplet or mapping.

Q20. How can you improve session performance in aggregatortransformation?Ans:

Use sorted input.

Q21. What is aggregate cache in aggregator transformation?Ans:


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The aggregator stores data in the aggregate cache until itcompletes aggregate calculations. When you run a session thatuses an aggregator transformation, the Informatica server createsindex and data caches in memory to process the transformation.If the Informatica server requires more space, it stores overflowvalues in cache files.

Q22. What are the difference between joiner transformation andsource qualifier transformation?Ans:

You can join heterogeneous data sources in joiner transformationwhich we can not achieve in source qualifier transformation.You need matching keys to join two relational sources in sourcequalifier transformation. Where as you doesn't need matching

keys to join two sources.Two relational sources should come from same datasource insource-qualifier. You can join relational sources which are comingfrom different sources also.

Q23. In which conditions we can not use joiner transformation(Limitations of joiner transformation)?Ans:

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 Normalizertransformation.

Both input pipelines originate from the same Joinertransformation.

Either input pipelines contains an Update Strategytransformation.

Either input pipelines contains a connected or unconnectedSequence Generator transformation.

Q24. What are the settings that you use to configure the joinertransformation?Ans:

Master and detail source Type of join Condition of the join

Q25. What are the join types in joiner transformation?Ans:

Normal (Default) Master outer Detail outer Full outer

Q26. What are the joiner caches?Ans:


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When a Joiner transformation occurs in a session, theInformatica Server reads all the records from the master sourceand builds index and data caches based on the master rows.After building the caches, the Joiner transformation readsrecords from the detail source and perform joins.

Q27.what is the look up transformation?

Ans:Use lookup transformation in your mapping to lookup data in arelational table, view and synonym.Informatica server queries the look up table based on the lookupports in the transformation. It compares the lookuptransformation port values to lookup table column values basedon the look up condition.

Q28. Why use the lookup transformation ?Ans:

To perform the following tasks.

Get a related value. For example, if your source table includesemployee 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 valuesused in a calculation, such as gross sales per invoice or salestax, but not the calculated value (such as net sales).

Update slowly changing dimension tables. You can use aLookup transformation to determine whether records alreadyexist in the target.

Q29. What are the types of lookup?Ans:

Connected and Unconnected

Q30. Differences between connected and unconnected lookup?Ans:

Connected Lookup Unconnected Lookup

1. Receives input values directly fromthe pipe line.

1. Receives input values from theresult of a lkp expression in aanother transformation.

2. You can use a dynamic or staticcache.

2. You can use a static cache.

3. Cache includes all lookup columns

used in the mapping.

3. Cache includes all lookup out

put ports in the lookup conditionand the lookup/return port.

4. Support user defined defaultvalues.

4. Does not support user defineddefault values.

Q31. Difference between static cache and dynamic cacheAns:


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Static cache Dynamic cache

1. You can not inert or update thecache.

1. You can insert rows into thecache as you pass to the target.

2. The Informatica server returns avalue from the lookup table oprcache when the condition is true.When the condition is not true, theInformatica server returns thedefault value for connectedtransformations and null forunconnected transformations.

2. The Informatica server insertsrows into cache when thecondition is false. This indicatesthat the row is not in the cacheor target table. You can passthese rows to the target table.

Q32. What is meant by lookup caches?Ans:

The Informatica server builds a cache in memory when itprocesses the first row of a data in a cached look uptransformation. It allocates memory for the cache based on theamount you configure in the transformation or session properties.

The Informatica server stores condition values in the index cache

and output values in the data cache.

Q33. What are the types of lookup caches?Ans:

Persistent cache: you can save the lookup cache files and reusethem the next time the Informatica server processes a lookuptransformation configured to use the cache.

Recache from database: If the persistent cache is notsynchronized with he lookup table, you can configure thelookup transformation to rebuild the lookup cache.

Static cache: you can configure a static or read only cache foronly lookup table. By default Informatica server creates astatic cache. It caches the lookup table and lookup values inthe 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 processes the lookuptransformation.

Dynamic cache: If you wants to cache the target table andinsert new rows into cache and the target, you can create alook up transformation to use dynamic cache. The Informaticaserver dynamically inserts data to the target table.

Shared cache: you can share the lookup cache betweenmultiple transactions. You can share unnamed cache between

transformations in the same mapping.

Q34. Which transformation should we use to normalize the COBOL

and relational sources?Ans:

Normalizer Transformation: When you drag the COBOL source into the mapping Designer workspace, the normalizer


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transformation automatically appears, creating input and outputports for every column in the source.

Q35. How the Informatica server sorts the string values in RankTransformation?Ans:

When the Informatica server runs in the ASCII data movement

mode it sorts session data using binary sort order. If youconfigure the session to use a binary sort order, the Informaticaserver calculates the binary value of each string and returns thespecified number of rows with the highest binary values for thestring.

Q36. What are the rank caches?

Ans:During the session, the Informatica server compares an input rowwith rows in the data cache. If the input row out-ranks a storedrow, the Informatica server replaces the stored row with the inputrow. The Informatica server stores group information in an index

cache and row data in a data cache.

Q37. What is the RANKINDEX in Rank Transformation?Ans:

The Designer automatically creates a RANKINDEX port for eachRank transformation. The Informatica Server uses the RankIndex port to store the ranking position for each record in agroup. For example, if you create a Rank transformation thatranks the top 5 salespersons for each quarter, the rank index

numbers the salespeople from 1 to 5.

38. What is the Router transformation?Ans:

A Router transformation is similar to a Filter transformationbecause both transformations allow you to use a condition totest data. However, a Filter transformation tests data for onecondition and drops the rows of data that do not meet thecondition. A Router transformation tests data for one or moreconditions and gives you the option to route rows of data that donot meet any of the conditions to a default output group.If you need to test the same input data based on multipleconditions, use a Router Transformation in a mapping instead of

creating multiple Filter transformations to perform the same task.

Q39. What are the types of groups in Router transformation?Ans:

Input group Output group


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the multiple targets, you can designate the order in whichInformatica server loads data into the targets.

Q47. What is the default join that source qualifier provides?Ans: Inner equi-join.

Q48. What are the basic needs to join two sources in a source

qualifier?Ans:

Two sources should have primary and foreign key relationships.

Two sources should have matching data types.Q49. What is update strategy transformation?Ans:

This transformation is used to maintain the history data or justmost recent changes in to target table.

Q50. Describe two levels in which update strategy transformation

sets?Ans:

Within a session: When you configure a session, you can instructthe Informatica Server to either treat all records in the same way(for example, treat all records as inserts), or use instructionscoded into the session mapping to flag records for differentdatabase operations.Within a mapping: Within a mapping, you use the UpdateStrategy transformation to flag records for insert, delete, update,or reject.

Q51. What is the default source option for update strategytransformation?Ans: Data Driven.

Q52. What is Data Driven?Ans:

The Informatica server follows instructions coded into updatestrategy transformations within the session mapping determinehow to flag records for insert, update, delete or reject.

If you does not choose data driven option setting, the Informaticaserver ignores all update strategy transformations in themapping.

Q53. What are the options in the target session of update strategytransformation?Ans:

Insert Delete Update Update as update


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Update as insert Update else insert Truncate table

Q54. What are the types of mapping wizards that are to be provided in

Informatica?Ans:

The Designer provides two mapping wizards to help you createmappings quickly and easily. Both wizards are designed to

create mappings for loading and maintaining star schemas, aseries of dimensions related to a central fact table.

1. Getting Started Wizard: Creates mappings to load static fact anddimension tables, as well as slowly growing dimension tables.

2. Slowly Changing Dimensions Wizard: Creates mappings to loadslowly changing dimension tables based on the amount ofhistorical dimension data you want to keep and the method youchoose to handle historical dimension data.

Q55. What are the types of mapping in Getting Started Wizard?Ans:

1. Simple Pass through mapping: Loads a static fact or dimensiontable by inserting all rows. Use this mapping when you want todrop all existing data from your table before loading new data.

2. Slowly Growing target: Loads a slowly growing fact or dimensiontable by inserting new rows. Use this mapping to load new datawhen existing data does not require updates.

Q56. What are the mappings that we use for slowly changing

dimension table?Ans:

SCD Type1: Rows containing changes to existing dimensions areupdated in the target by overwriting the existing dimension. Inthe Type 1 Dimension mapping, all rows contain currentdimension data.Use the Type 1 Dimension mapping to update a slowly changingdimension table when you do not need to keep any previousversions of dimensions in the table.

SCD Type 2: The Type 2 Dimension Data mapping inserts bothnew and changed dimensions into the target. Changes aretracked in the target table by versioning the primary key andcreating a version number for each dimension in the table.Use the Type 2 Dimension/Version Data mapping to update aslowly changing dimension table when you want to keep a fullhistory of dimension data in the table. Version numbers andversioned primary keys track the order of changes to eachdimension.

SCD Type 3: The Type 3 Dimension mapping filters source rowsbased on user-defined comparisons and inserts only those found


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to be new dimensions to the target. Rows containing changes toexisting dimensions are updated in the target. When updating anexisting dimension, the Informatica Server saves existing data indifferent columns of the same row and replaces the existing datawith the updates

Q57. What are the different types of Type2 dimension mapping?

Ans:Type2 Dimension/Version Data Mapping: In this mapping theupdated dimension in the source will gets inserted in target alongwith a new version number. And newly added dimension insource will inserted into target with a primary key.

Type2 Dimension/Flag current Mapping: This mapping is also

used for slowly changing dimensions. In addition it creates a flagvalue for changed or new dimension.Flag indicates the dimension is new or newly updated. Recentdimensions will gets saved with current flag value 1. And updateddimensions are saved with the value 0.

Type2 Dimension/Effective Date Range Mapping: This is also oneflavor of Type2 mapping used for slowly changing dimensions.

This mapping also inserts both new and changed dimensions in

to the target. And changes are tracked by the effective date rangefor each version of each dimension.

Q58. How can you recognize whether or not the newly added rows inthe source are gets insert in the target?

Ans:In the Type2 mapping we have three options to recognize the

newly added rows,a. Version number.b. Flag value.c. Effective date Range.

Q59. What are two types of processes that Informatica runs thesession?Ans:

Load manager Process: Starts the session, creates the DTMprocess, and sends post-session email when the sessioncompletes.

The DTM process: Creates threads to initialize the session, read,write, and transform data, and handle pre- and post-sessionoperations.

Q60. What are the new features of the server manager in theInformatica v5.0?

Ans:


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You can use command line arguments for a session or batch.This allows you to change the values of session parameters, andmapping parameters and mapping variables.Parallel data processing: This feature is available for PowerCenteronly. If we use the Informatica server on a SMP system, you canuse multiple CPU's to process a session concurrently.Process session data using threads: Informatica server runs the

session in two processes. Explained in previous question.

Q61. Can you generate reports in Informatica?Ans:

Yes, by using Metadata Reporter we can generate reports inInformatica.

Q62. What is metadata reporter?Ans:

It is a web based application that enables you to run reportsagainst repository metadata.With a metadata reporter, you can access information about your

repository with out having knowledge of sql, transformationlanguage or underlying tables in the repository.

Q63. Define mapping and sessions?

Ans:Mapping: It is a set of source and target definitions linked bytransformation objects that define the rules for transformation.Session: It is a set of instructions that describe how and when tomove data from source to targets.

Q64. Which tool you use to create and manage sessions and batches

and to monitor and stop the Informatica server?Ans: Informatica Server Manager.

65. Why we use partitioning the session in Informatica?Ans:

Partitioning achieves the session performance by reducing thetime period of reading the source and loading the data into target.

66. To achieve the session partition what are the necessary tasks youhave to do?Ans:

Configure the session to partition source data. Install the Informatica server on a machine with multiple CPU's.

Q67. How the Informatica server increases the session performancethrough partitioning the source?Ans:

For relational sources Informatica server creates multipleconnections for each partition of a single source and extractsseparate range of data for each connection. Informatica server


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reads multiple partitions of a single source concurrently.Similarly for loading also Informatica server creates multipleconnections to the target and loads partitions of dataconcurrently.For XML and file sources, Informatica server reads multiple filesconcurrently. For loading the data Informatica server creates aseparate file for each partition (of a source file).U can choose to

merge the targets.

Q68. Why you use repository connectivity?Ans:

When you edit, schedule the session each time, Informaticaserver directly communicates the repository to check whether ornot the session and users are valid. All the metadata of sessions

and mappings will be stored in repository.

Q69. What are the tasks that Load Manager Process will do?Ans:

Manages the session and batch scheduling: When you start theInformatica server the load manager launches and queries therepository for a list of sessions configured to run on theInformatica server. When you configures the session the load

manager maintains list of list of sessions and session starttimes. When you start a session load manger fetches the sessioninformation from the repository to perform the validations andverifications prior to starting DTM process.

Locking and reading the session: When the Informatica serverstarts a session load manager locks the session from therepository. Locking prevents you starting the session again andagain.

Reading the parameter file: If the session uses a parameter files,load manager reads the parameter file and verifies that thesession level parameters are declared in the file

Verifies permission and privileges: When the session starts loadmanger checks whether or not the user have privileges to runthe session.

Creating log files: Load manger creates log file contains thestatus of session.

Q70. What is DTM process?

Ans:

After the load manger performs validations for session, it createsthe DTM process. DTM is to create and manage the threads thatcarry out the session tasks. It creates the master thread. Masterthread creates and manages all the other threads.

Q71. What are the different threads in DTM process?Ans:

Master thread: Creates and manages all other threads.


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Mapping thread: One mapping thread will be creates for eachsession. Fetches session and mapping information.

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

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

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

Q72. What are the data movement modes in Informatica?Ans:

Data movement modes determine how Informatica server handlesthe character data. You choose the datamovement in theInformatica server configuration settings. Two types ofdatamovement modes available in Informatica.

ASCII mode. Unicode mode.

Q73. What are the output files that the Informatica server createsduring the session running?Ans:

Informatica server log: Informatica server (on UNIX) creates a logfor all status and error messages (default name: pm.server.log).It also creates an error log for error messages. These files will becreated in Informatica home directory.

Session log file: Informatica server creates session log file foreach session. It writes information about session into log filessuch as initialization process, creation of sql commands forreader and writer threads, errors encountered and loadsummary. The amount of detail in session log file depends on

the tracing level that you set. Session detail file: This file contains load statistics for each

targets in mapping. Session details include information such astable name, number of rows written or rejected. You can viewthis file by double clicking on the session in monitor window

Performance detail file: This file contains information known assession performance details which helps you where performancecan be improved. To generate this file select the performancedetail option in the session property sheet.

Reject file: This file contains the rows of data that the writerdoes not write to targets.

Control file: Informatica server creates control file and a targetfile when you run a session that uses the external loader. Thecontrol file contains the information about the target flat filesuch as data format and loading instructions for the externalloader.

Post session email: Post session email allows you toautomatically communicate information about a session run to

designated recipients. You can create two different messages.


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One if the session completed successfully the other if thesession fails.

Indicator file: If you use the flat file as a target, you canconfigure the Informatica server to create indicator file. For each

target row, the indicator file contains a number to indicatewhether the row was marked for insert, update, delete or reject.

Output file: If session writes to a target file, the Informaticaserver creates the target file based on file properties entered inthe session property sheet.

Cache files: When the Informatica server creates memory cacheit also creates cache files. For the following circumstancesInformatica server creates index and data cache files.

o Aggregator transformation.o Joiner transformation.o Rank transformation.o Lookup transformation.

Q74. In which circumstances that Informatica server creates Rejectfiles?

Ans:

When it encounters the DD_Reject in update strategytransformation.

Violates database constraint. Filed in the rows was truncated or overflowed.

Q75. What is polling?Ans:

It displays the updated information about the session in themonitor window. The monitor window displays the status of each

session when you poll the Informatica server.

Q76. Can you copy the session to a different folder or repository?Ans:

Yes, by using copy session wizard you can copy a session in adifferent folder or repository. But that target folder or repositoryshould consists of mapping of that session. If target folder orrepository is not having the mapping of copying session, youshould have to copy that mapping first before you copy thesession.

Q77. What is batch and describe about types of batches?

Ans:Grouping of session is known as batch. Batches are two types

Sequential: Runs sessions one after the other. Concurrent: Runs session at same time.If you have sessions with source-target dependencies you have togo for sequential batch to start the sessions one after another. If

you have several independent sessions you can use concurrentbatches. Which runs all the sessions at the same time.


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Q78. Can you copy the batches?Ans: NO

Q79. How many number of sessions that you can create in a batch?Ans: Any number of sessions.

Q80. When the Informatica server marks that a batch is failed?Ans:

If one of session is configured to "run if previous completes" andthat previous session fails.

Q81. What is a command that used to run a batch?Ans: pmcmd is used to start a batch.

Q82. What are the different options used to configure the sequentialbatches?Ans:

Two options

Run the session only if previous session completes successfully. Always runs the session.

Q83. In a sequential batch can you run the session if previous sessionfails?Ans: Yes, by setting the option always runs the session.

Q84. Can you start a batches with in a batch?Ans:

You can not. If you want to start batch that resides in a batch,create a new independent batch and copy the necessary sessions

into the new batch.

Q85. Can you start a session inside a batch individually?Ans:

We can start our required session only in case of sequentialbatch. In case of concurrent batch we cant do like this.

Q86. How can you stop a batch?Ans: By using server manager or pmcmd.

Q87. What are the session parameters?Ans:

Session parameters are like mapping parameters, representvalues you might want to change between sessions such asdatabase connections or source files.Server manager also allows you to create user defined sessionparameters. Following are user defined session parameters.

Database connections


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Source file names: use this parameter when you wants tochange the name or location of session source file betweensession runs.

Target file names: Use this parameter when you wants tochange the name or location of session target file betweensession runs.

Reject file names: Use this parameter when you want tochange the name or location of session reject files betweensession runs.

Q88. What is parameter file?Ans:

Parameter file is to define the values for parameters and variablesused in a session. A parameter file is a file created by text editorsuch as word pad or notepad.

you can define the following values in parameter file,

Mapping parameters. Mapping variables.

Session parameters.

Q89. How can you access the remote source into your session?Ans:

Relational source: To access relational source which is situatedin a remote place, you need to configure database connection tothe datasource.

FileSource: To access the remote source file you must configurethe FTP connection to the host machine before you create the

session.

Heterogeneous: When your mapping contains more than onesource type, the server manager creates a heterogeneous

session that displays source options for all types.

Q90. What is difference between portioning of relational target andpartitioning of file targets?Ans:

If you partition a session with a relational target Informatica

server creates multiple connections to the target database to writetarget data concurrently. If you partition a session with a filetarget the Informatica server creates one target file for eachpartition. You can configure session properties to merge thesetarget files.

Q91. What are the transformations that restrict the partitioning of

sessions?Ans:

Advanced External procedure transformation and Externalprocedure transformation: This transformation contains a checkbox on the properties tab to allow partitioning.

Aggregator Transformation: If you use sorted ports you can notpartition the associated source


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Joiner Transformation: you can not partition the master sourcefor a joiner transformation

Normalizer Transformation: XML targets.Q92. Performance tuning in Informatica?Ans:

The goal of performance tuning is optimize session performance

so sessions run during the available load window for theInformatica Server. Increase the session performance byfollowing.

The performance of the Informatica Server is related to networkconnections. Data generally moves across a network at lessthan 1 MB per second, whereas a local disk moves data five totwenty times faster. Thus network connections often affect onsession performance. So avoid network connections.

Flat files: If your flat files stored on a machine other than theInformatica server, move those files to the machine that consistsof 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 sessionperformance.

Staging areas: If you use staging areas you force Informaticaserver to perform multiple datapasses. Removing of stagingareas may improve session performance.

U can run the multiple Informatica servers against the samerepository. Distributing the session load to multiple Informaticaservers may improve session performance.

Run the Informatica server in ASCII datamovement modeimproves the session performance. Because ASCIIdatamovement 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, singletable select statements with an ORDER BY or GROUP BY clausemay benefit from optimization such as adding indexes.

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

If you are target consists key constraints and indexes you slowthe loading of data. To improve the session performance in thiscase drop constraints and indexes before you run the sessionand rebuild them after completion of session.

Running parallel sessions by using concurrent batches will alsoreduce the time of loading the data. So concurrent batches mayalso increase the session performance.


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Partitioning the session improves the session performance bycreating multiple connections to sources and targets and loadsdata in parallel pipe lines.

In some cases if a session contains an aggregatortransformation, you can use incremental aggregation to improvesession performance.

Avoid transformation errors to improve the session performance. If the session contain lookup transformation you can improve

the session performance by enabling the look up cache.

If your session contains filter transformation, create that filtertransformation nearer to the sources or you can use filtercondition in source qualifier.

Aggregator, Rank and Joiner transformation may oftenlydecrease the session performance .Because they must group

data before processing it. To improve session performance inthis case use sorted ports option.

Q92. What is difference between mapplet and reusable

transformation?Ans:

Mapplet consists of set of transformations that is reusable. Areusable transformation is a single transformation that can bereusable.

If you create a variables or parameters in mapplet that can notbe used in another mapping or mapplet. Unlike the variables

that are created in a reusable transformation can be useful inany other mapping or mapplet.

We can not include source definitions in reusabletransformations. But we can add sources to a mapplet.

Whole transformation logic will be hided in case of mapplet. Butit is transparent in case of reusable transformation.

We cant use COBOL source qualifier, joiner, normalizertransformations in mapplet. Where as we can make them as areusable transformations.

Q93. Define Informatica repository?Ans:

The Informatica repository is a relational database that storesinformation, or metadata, used by the Informatica Server andClient tools. Metadata can include information such asmappings describing how to transform source data, sessions

indicating when you want the Informatica Server to perform thetransformations, and connect strings for sources and targets.

The repository also stores administrative information such asusernames and passwords, permissions and privileges, andproduct version.

Use repository manager to create the repository. The RepositoryManager connects to the repository database and runs the code

needed to create the repository tables. These tables stores


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metadata in specific format the Informatica server, client toolsuse.

Q94. What are the types of metadata that stores in repository?Ans:

Following are 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 definitions. Transformations.

Q95. What is power center repository?Ans:

The PowerCenter repository allows you to share metadata acrossrepositories to create a data mart domain. In a data mart domain,

you can create a single global repository to store metadata usedacross an enterprise, and a number of local repositories to sharethe global metadata as needed.

Q96. How can you work with remote database in Informatica? Did youwork directly by using remote connections?Ans:

To work with remote datasource you need to connect it withremote connections. But it is not preferable to work with thatremote source directly by using remote connections. Instead youbring that source into you are local machine where Informatica

server resides. If you work directly with remote source the sessionperformance will decreases by passing less amount of data acrossthe network in a particular time.

Q97. What are the new features in Informatica 5.0?Ans:

U can debug your mapping in mapping designer. U can view the work space over the entire screen. The designer displays a new icon for a invalid mappings in the

navigator window.

U can use a dynamic lookup cache in a lookup transformation. Create mapping parameters or mapping variables in a mapping

or mapplet to make mappings more flexible.

U can export objects into repository and import objects fromrepository. When you export a repository object, the designer or


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server manager creates an XML file to describe the repositorymetadata.

The designer allows you to use Router transformation to testdata for multiple conditions. Router transformation allows you

route groups of data to transformation or target.

U can use XML data as a source or target.Server Enhancements:

U can use the command line program pmcmd to specify aparameter file to run sessions or batches. This allows you tochange 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 asession concurrently. You configure partitions in the sessionproperties based on source qualifiers. The Informatica Serverreads, transforms, and writes partitions of data in parallel for asingle session. This is available for Power center only.Informatica server creates two processes like load manager

process, DTM process to run the sessions.Metadata Reporter: It is a web based application which is used torun reports against repository metadata.U can copy the session across the folders and repositories usingthe copy session wizard in the Informatica server manager.With new email variables, you can configure post-session email toinclude information, such as the mapping used during the

session

Q98. What is incremental aggregation?Ans:

When using incremental aggregation, you apply captured changesin the source to aggregate calculations in a session. If the sourcechanges only incrementally and you can capture changes, youcan configure the session to process only those changes. Thisallows the Informatica Server to update your target incrementally,rather than forcing it to process the entire source and recalculatethe same calculations each time you run the session.

Q99. What are the scheduling options to run a session?

Ans:You can schedule a session to run at a given time or interval, or

you can manually run the session.

Different options of scheduling

Run only on demand: Informatica server runs the session onlywhen user starts session explicitly.

Run once: Informatica server runs the session only once at aspecified date and time.

Run every: Informatica server runs the session at regularintervals as you configured.


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Customized repeat: Informatica server runs the session at thedates and times specified in the repeat dialog box.

Q100 .What is tracing level and what are the types of tracing level?

Ans:Tracing level represents the amount of information that Informaticaserver writes in a log file.

Types of tracing level Normal Verbose Verbose init Verbose data

Q101. What is difference between stored procedure transformationand external procedure transformation?Ans:

In case of stored procedure transformation procedure will becompiled and executed in a relational data source. You need data

base connection to import the stored procedure in to yourmapping. Where as in external procedure transformationprocedure or function will be executed out side of data source. We

you need to make it as a DLL to access in you are mapping. Noneed to have data base connection in case of external proceduretransformation.

Q102. Explain about Recovering sessions?Ans:

If you stop a session or if an error causes a session to stop, refer tothe session and error logs to determine the cause of failure. Correctthe 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 acommit.

Truncate the target tables and run the session again if thesession is not recoverable.

Consider performing recovery if the Informatica Server hasissued at least one commit.

Q103. If a session fails after loading of 10,000 records in to the target.

How can you load the records from 10001st record when you run thesession next time?Ans:

As explained above Informatica server has 3 methods torecovering the sessions. Use performing recovery to load therecords from where the session fails.

Q104. Explain about perform recovery?

Ans:


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When the Informatica Server starts a recovery session, it readsthe OPB_SRVR_RECOVERY table and notes the row ID of thelast row committed to the target database. The InformaticaServer then reads all sources again and starts processing from

the next row ID.

For example, if the Informatica Server commits 10,000 rowsbefore the session fails, when you run recovery, the Informatica

Server bypass the rows up to 10,000 and starts loading withrow 10,001.

By default, Perform Recovery is disabled in the InformaticaServer setup. You must enable Recovery in the InformaticaServer setup before you run a session so the Informatica Servercan create and/or write entries in the OPB_SRVR_RECOVERYtable.

Q105. How to recover the standalone session?Ans:

A standalone session is a session that is not nested in a batch. Ifa standalone session fails, you can run recovery using a menucommand or pmcmd. These options are not available for batchedsessions.

To recover sessions using the menu:

In the Server Manager, highlight the session you want torecover.

Select Server Requests-Stop from the menu. With the failed session highlighted, select Server Requests-

Start Session in Recovery Mode from the menu.

To recover sessions using pmcmd:

From the command line, stop the session. From the command line, start recovery.

Q106. How can you recover the session in sequential batches?Ans:

If you configure a session in a sequential batch to stop on failure,you can run recovery starting with the failed session. TheInformatica Server completes the session and then runs the restof the batch. Use the Perform Recovery session property torecover sessions in sequential batches configured to stop onfailure:

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 thesession, the Informatica Server attempts to recover the previous

session. If you do not configure a session in a sequential batch to


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stop on failure, and the remaining sessions in the batchcomplete, recover the failed session as a standalone session.

Q107. How to recover sessions in concurrent batches?Ans:

If multiple sessions in a concurrent batch fail, you might want totruncate all targets and run the batch again. However, if a

session in a concurrent batch fails and the rest of the sessionscomplete successfully, you can recover the session as astandalone 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.

Q108. How can you complete unrecoverable sessions?

Ans:

Under certain circumstances, when a session does notcomplete, you need to truncate the target tables and run the

session from the beginning.

Run the session from the beginning when the Informatica Servercannot run recovery or when running recovery might result ininconsistent data.

Q109. What are the circumstances that Informatica server results anunrecoverable session?Ans:

The source qualifier transformation does not use sorted ports. If you changes the partition information after the initial session

fails.

Perform recovery is disabled in the Informatica serverconfiguration.

If the sources or targets changes after initial session fails. If the mapping consists of sequence generator or normalizer

transformation.

If a concurrent batches contains multiple failed sessions.Q110. If I done any modifications for my table in back end does it

reflect in Informatica warehouse or mapping designer or sourceanalyzer?Ans:

NO, Informatica is not at all concern with back end data base. Itdisplays you all the information that is to be stored in repository.If want to reflect back end changes to Informatica screens, again

you have to import from back end to Informatica by validconnection. And you have to replace the existing files with

imported files.


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Q111. After dragging the ports of three sources (sql server, oracle,Informix) to a single source-qualifier, can you map these three portsdirectly to target?Ans:

NO, unless and until you join those three ports in source qualifieryou cannot map them directly.

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