Informatica PowerCenter 8x Key Concepts – 2

The PowerCenter Repository is one of best metadata storage among all ETL products. The repository is sufficiently normalized to store metadata at a very detail level; which in turn means the Updates to therepository are very quick and the overall Team-based Development is smooth. The repository data structure is also useful for the users to do analysis and reporting.

Accessibility to the repository through MX views and SDK kit extends the repositories capability from a simple storage of technical data to a database for analysis of the ETL metadata.

PowerCenter Repository is a collection of 355 tables which can be created on any major relational database. The kinds of information that are stored in the repository are,

1. Repository configuration details
2. Mappings
3. Workflows
4. User Security
5. Process Data of session runs

For a quick understanding,

When a user creates a folder, corresponding entries are made into table OPB_SUBJECT; attributes like folder name, owner id, type of the folder like shared or not are all stored.
When we create\import sources and define field names, datatypes etc in source analyzer entries are made into opb_src and OPB_SRC_FLD.
When target and related fields are created/imported from any database entries are made into tables like OPB_TARG and OPB_TARG_FLD.
Table OPB_MAPPING stores mapping attributes like Mapping Name, Folder Id, Valid status and mapping comments.
Table OPB_WIDGET stores attributes like widget type, widget name, comments etc. Widgets are nothing but the Transformations which Informatica internally calls them as Widgets.
Table OPB_SESSION stores configurations related to a session task and table OPB_CNX_ATTR stores information related to connection objects.
Table OPB_WFLOW_RUN stores process details like workflow name, workflow started time, workflow completed time, server node it ran etc.
REP_ALL_SOURCES, REP_ALL_TARGETS and REP_ALL_MAPPINGS are few of the many views created over these tables.

PowerCenter applications access the PowerCenter repository through the Repository Service. The Repository Service protects metadata in the repository by managing repository connections and using object-locking to ensure object consistency.

We can create a repository as global or local. We can go for‘global’ to store common objects that multiple developers can use through shortcuts and go for local repository to perform of development mappings and workflows. From a local repository, we can create shortcuts to objects in shared folders in the global repository. PowerCenter supports versioning. A versioned repository can store multiple versions of an object.

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Handling Oracle Exceptions

There may be requirements wherein certain oracle exceptions need to be treated as Warnings and certain exceptions need to be treated as Fatal.

Normally, a fatal Oracle error may not be registered as a warning or row error and the session may not fail, conversely a non-fatal error may cause a PowerCenter session to fail.This can be changed with few tweaking in

A. Oracle Stored Procedure

B. The Oracle ErrorActionFile and

C. Server Settings

Let us see this with an example.

An Oracle Stored Procedure under certain conditions returns the exception NO_DATA_FOUND. When this exception occurs, the session calling the Stored Procedure does not fail.

Adding an entry for this error in the ora8err.act file and enabling the OracleErrorActionFile option does not change this behavior (Both ora8err.act and OracleErrorActionFile are discussed in later part of this blog).

When this exception (NO_DATA_FOUND) is raised in PL/SQL it is sent to the Oracle client as an informational message not an error message and the Oracle client sends this message to PowerCenter. Since the Oracle client does not return an error to PowerCenter the session continues as normal and will not fail.

A. Modify the Stored Procedure to return a different exception or a custom exception. A custom exception number (only between -20000 and -20999) can be sent using the raise_application_error PL/SQL command as follows:

raise_application_error (-20991,’<stored procedure name> has raised an error’, true);

Additionally add the following entry to the ora8err.act file:

20991, F

B. Editing the Oracle Error Action file can be done as follows:

1. Go to the server/bin directory under the Informatica Services installation directory (8.x) or the Informatica Server installation directory (7.1.x).

E.g.,

For Infa 7.x

C:\Program Files\Informatica PowerCenter 7.1.3\Server\ora8err.act

For Infa 8.x

C:\Informatica\PowerCenter8.1.1\server\bin

2. Open the ora8err.act file.

3. Change the value associated with the error.
“F” is fatal and stops the session.
“R” is a row error and writes the row to the reject file and continues to the next row.

Examples:

To fail a session when the ORA-03114 error is encountered change the 03114 line in the file to the following:

03114, F

To return a row error when the ORA-02292 error is encountered change the 02292 line to the following:

02292, R

Note that the Oracle action file only applies to native Oracle connections in the session. If the target is using the SQL*Loader external loader option, the message status will not be modified by the settings in this file.

C. Once the file is modified, following changes need to be done in the server level.

Infa 8.x

Set the OracleErrorActionFile Integration Service Custom Property to the name of the file (ora8err.act by default) as follows:

1. Connect to the Administration Console.

2. Stop the Integration Service.

3. Select the Integration Service.

4. Under the Properties tab, click Edit in the Custom Properties section.

5. Under Name enter OracleErrorActionFile.

6. Enter ora8err.act for the parameter under Value.

7. Click OK.

8. Start the Integration Service.

PowerCenter 7.1.x

In PowerCenter 7.1.x do the following:

UNIX

For the server running on UNIX:

1. Using a text editor open the PowerCenter server configuration file (pmserver.cfg).

2. Add the following entry to the end of the file:

OracleErrorActionFile=ora8err.act

3. Re-start the PowerCenter server (pmserver).

Windows

For the server running on Windows:

1. Click Start, click Run, type regedit, and click OK.
2. Go to the following registry key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\
PowerMart\Parameters\Configuration

Select Edit; New; String Value. Enter the “OracleErrorActionFile” for the string value.
Select Edit; Modify.

Enter the directory and the file name of the Oracle error action file:

\ora8err.act

Example:

The default entry for PowerCenter 7.1.3 would be:
C:\Program Files\Informatica PowerCenter 7.1.3\Server\ora8err.act

And for PowerCenter8.1.1 it would be
C:\Informatica\PowerCenter8.1.1\server\bin

Click OK

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Informatica Exceptions – 3

Here are few more Exceptions:

1. There are occasions where sessions fail with the following error in the Workflow Monitor:

“First error code [36401], message [ERROR: Session task instance [session XXXX]: Execution terminated unexpectedly.] “

where XXXX is the session name.

The server log/workflow log shows the following:

“LM_36401 Execution terminated unexpectedly.”

To determine the error do the following:

a. If the session fails before initialization and no session log is created look for errors in Workflow log and pmrepagent log files.

b. If the session log is created and if the log shows errors like

“Caught a fatal signal/exception” or

“Unexpected condition detected at file [xxx] line yy”

then a core dump has been created on the server machine. In this case Informatica Technical Support should be contacted with specific details. This error may also occur when the PowerCenter server log becomes too large and the server is no longer able to write to it. In this case a workflow and session log may not be completed. Deleting or renaming the PowerCenter Server log (pmserver.log) file will resolve the issue.

2. Given below is not an exception but a scenario which most of us would have come across.

Rounding problem occurs with columns in the source defined as Numeric with Precision and Scale or Lookups fail to match on the same columns. Floating point arithmetic is always prone to rounding errors (e.g. the number 1562.99 may be represented internally as 1562.988888889, very close but not exactly the same). This can also affect functions that work with scale such as the Round() function. To resolve this do the following:

a. Select the Enable high precision option for the session.

b. Define all numeric ports as Decimal datatype with the exact precision and scale desired. When high precision processing is enabled the PowerCenter Server support numeric values up to 28 digits. However, the tradeoff is a performance hit (actual performance really depends on how many decimal ports there are).

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Exceptions in Informatica – 2

Let us see few more strange exceptions in Informatica

1. Sometimes the Session fails with the below error message.
“FATAL ERROR : Caught a fatal signal/exception
FATAL ERROR : Aborting the DTM process due to fatal signal/exception.”

There might be several reasons for this. One possible reason could be the way the function SUBSTR is used in the mappings, like the length argument of the SUBSTR function being specified incorrectly.
Example:

IIF(SUBSTR(MOBILE_NUMBER, 1, 1) = ‘9′,
SUBSTR(MOBILE_NUMBER, 2, 24),
MOBILE_NUMBER)

In this example MOBILE_NUMBER is a variable port and is 24 characters long.
When the field itself is 24 char long, the SUBSTR starts at position 2 and go for a length of 24 which is the 25th character.

To solve this, correct the length option so that it does not go beyond the length of the field or avoid using the length option to return the entire string starting with the start value.
Example:

In this example modify the expression as follows:

IIF(SUBSTR(MOBILE_NUMBER, 1, 1) = ‘9′,
SUBSTR(MOBILE_NUMBER, 2, 23),
MOBILE_NUMBER)

OR

IIF(SUBSTR(MOBILE_NUMBER, 1, 1) = ‘9′,
SUBSTR(MOBILE_NUMBER, 2),
MOBILE_NUMBER).

2. The following error can occur at times when a session is run

“TE_11015 Error in xxx: No matching input port found for output port OUTPUT_PORT TM_6006 Error initializing DTM for session…”

Where xxx is a Transformation Name.

This error will occur when there is corruption in the transformation.
To resolve this do one of the following: * Recreate the transformation in the mapping having this error.

3. At times you get the below problems,

1. When opening designer, you get “Exception access violation”, “Unexpected condition detected”.

2. Unable to see the navigator window, output window or the overview window in designer even after toggling it on.

3. Toolbars or checkboxes are not showing up correctly.

These are all indications that the pmdesign.ini file might be corrupted. To solve this, following steps need to be followed.

1. Close Informatica Designer
2. Rename the pmdesign.ini (in c:\winnt\system32 or c:\windows\system).
3. Re-open the designer.

When PowerMart opens the Designer, it will create a new pmdesign.ini if it doesn’t find an existing one. Even reinstalling the PowerMart clients will not create this file if it finds one.

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Informatica PowerCenter 8x Key Concepts – 1

We shall look at the fundamental components of the Informatica PowerCenter 8.x Suite, the key components are

1. PowerCenter Domain
2. PowerCenter Repository
3. Administration Console
4. PowerCenter Client
5. Repository Service
6. Integration Service

PowerCenter Domain

A domain is the primary unit for management and administration of services in PowerCenter. Node, Service Manager and Application Services are components of a domain.

Node

Node is the logical representation of a machine in a domain. The machine in which the PowerCenter is installed acts as a Domain and also as a primary node. We can add other machines as nodes in the domain and configure the nodes to run application services such as the Integration Service or Repository Service. All service requests from other nodes in the domain go through the primary node also called as ‘master gateway’.

The Service Manager

The Service Manager runs on each node within a domain and is responsible for starting and running the application services. The Service Manager performs the following functions,

• Alerts. Provides notifications of events like shutdowns, restart
• Authentication. Authenticates user requests from the Administration Console, PowerCenter Client, Metadata Manager, and Data Analyzer
• Domain configuration. Manages configuration details of the domain like machine name, port
• Node configuration. Manages configuration details of a node metadata like machine name, port
• Licensing. When an application service connects to the domain for the first time the licensing registration is performed and for subsequent connections the licensing information is verified
• Logging. Manages the event logs from each service, the messages could be ‘Fatal’, ‘Error’, ‘Warning’, ‘Info’
• User management. Manages users, groups, roles, and privileges

Application services

The services that essentially perform data movement, connect to different data sources and manage data are called Application services, they are namely Repository Service, Integration Service, Web Services Hub, SAPBW Service, Reporting Service and Metadata Manager Service. The application services run on each node based on the way we configure the node and the application service

Domain Configuration

Some of the configurations for a domain involves assigning host name, port numbers to the nodes, setting up Resilience Timeout values, providing connection information of metadata Database, SMTP details etc. All the Configuration information for a domain is stored in a set of relational database tables within the repository. Some of the global properties that are applicable for Application Services like ‘Maximum Restart Attempts’, ‘Dispatch Mode’ as ‘Round Robin’/’Metric Based’/’Adaptive’ etc are configured under Domain Configuration

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