Thursday, June 12, 2008

ODS

An operational data store (ODS) is a type of database often used as an interim area for a data warehouse. Unlike a data warehouse, which contains static data, the contents of the ODS are updated through the course of business operations. An ODS is designed to quickly perform relatively simple queries on small amounts of data (such as finding the status of a customer order), rather than the complex queries on large amounts of data typical of the data warehouse. An ODS is similar to your short term memory in that it stores only very recent information; in comparison, the data warehouse is more like long term memory in that it stores relatively permanent information.

Sequence of values for mapping parameters/variables to be picked by integration service:

Whenever an integration service encounters any mapping parameter/variable, it takes its value in following sequence:
1> looks into parameter file
2> looks into repository table
3> looks into the mapping, if any default value specified to it
4> takes the default value as per the informatica standards for that data type

Monday, June 9, 2008

Some Infa Definitions

Degenerated Dimension: The dimensions which are available in the fact table without having any attributes to it or not having different dimensional table for it, e.g. year

Conformed Dimension: The dimensions which are being used in more than one star schemas, e.g. date dimension being used in inventory as well as purchase schema

Saturday, June 7, 2008

ora-01555: snapshot too old

hi,

while loading data from one table having at least 2.5 million records to another oracle table through Informatica mapping, I encountered following problem yesterday:

READER_2_1_1> RR_4035 SQL Error [ORA-01555: snapshot too old: rollback segment number 7with name "_7$" too small

I tried to reduce the commit interval in from 10,000 to 500 and ran the session, but still it did not ran successfully and given above error message. So, I changed the commit interval to 20000 and still it got failed.

So, finally we had asked to our DBA about this, and he ressolved the problem.
Wow, the solution was just to increase the UNDO tablespace for that database where that table is residing.
So, go and ask your DBA to increase the UNDO tablespace.

That's all.

Introduction

Hi all,

This blog is related to the data warehousing tool- Informatica: a well known ETL tool.

This blog will give you following informrtion:

Domain: Datawarehousing

Specialization: Informatica

Related Topics: All ETL Tools (Datastage, DI, DTS etc.,)