Ab Initio Interview Questions and Answers

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Ab Initio Interview Questions
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#Ab Initio Interview Questions and Answers

Ab Initio Interview Questions and Answers

What does dependency analysis mean in Ab Initio?

In Ab Initio, Dependency analysis will answer the questions regarding datalinage. That is where does the data come from,what applications produce and depend on this data etc.

We can retrieve the maximum (surrogate key) from the existing data,the by using scan or next_in_sequence/reformat we can generate further sequence for new records.

What methods exist for performance tuning?

The best way would be to perform join at the database, the classical way is when we have two tables that we can bring together by making placing a join component between them. Alternately we can write a query to make the join at the level of a database. The advantage is that only one hit is sent to the database instead of two (the classical method). This makes a real difference in improving performance.

What means writing of wrapper?

Writing of a wrapper will help us run sequential running of two graphs, for instance in order to do this the user must use that feed that was generated by the first graph into the next graph, and for multiple use into the next graph and so on.

What is the reason for using parameterized graphs?

Their role is seen when we are trying to use the same graph many times for various files, in this way we must set parameters for the graph, which get replaced anyway during run. So we can keep one graph version for different files and not different versions.

Explain the difference between the truncate and delete commands? Ab Initio Interview Questions and Answers

It is a DDL command, used to delete tables or clusters. Since it is a DDL command hence it is auto commit and Rollback can’t be performed. It is faster than delete.

It is DML command, generally used to delete a record, clusters or tables. Rollback command can be performed , in order to retrieve the earlier deleted things. To make deleted things permanently, “commit” command should be used.

What is the difference between rollup and scan?

By using rollup we cant generate cumulative summary records for that we will be using scan.

How can i run the 2 GUI merge files?

Do you mean by merging Gui map files in WR.If so, by merging GUI map files in GUI map editor it wont create corresponding test script.without test script you cant run a file.So it is impossible to run a file by merging 2 GUI map files.

What is API mode versus the utility mode?

Both API and utility modes are used as connection interfaces to the databases for the purpose of performing specific tasks required by the user. They allows us to easily access different functions that the vendor put for use. The role of each function is related to the nature of the databases. The difference between the two modes is that API is known to be slower but offers a higher range of flexibility than the utility mode. Also API is considered to be a more diagnostic feature.

What is the reason for a database to contain stored procedures?

The main reason is network traffic reduction. Because stored procedures are precompiled SQL blocks, the time of execution can be reduced. In this way the application performance is higher, being stored in the database the procedure will be called by the application and execute faster than in the case is not already compiled. They also provide reusability for different other applications.

What difference does exist between Checkpoint and Phase?

What phasing does is deleting the intermediate (temporary) files before a new phase begins which is different from checkpointing. The checkpoints keep the temporary files until we finish the graph, so in case of failing we can restore the last good process. The phase doesn’t have this advantage.

What role has the XFR function?

The purpose of this function is usually to store mappings and this is very useful because the rewriting of code takes time and the XFR spares us of this effort.

What possible errors we can receive from a graph execution?

The compilation errors in Ab Inition can appear when for example the output DML is not as the input DML.

What is the purpose of ramp limit?

The limit parameter is representing how much reject events exist and is an integer, while the limit parameter is the rate of reject events that the records processed has, it is a real number.

What is the role of a driving port?

Driving port is usually meant for graph performance enhancement.

What can we say about partitioning with key and round robin?

The partitioning with key (also called hash partition) is partitioning method used when we have diverse keys. The technique is used basically in the processing of parallel data. On the other hand round robin partitioning is a technique that allows us to distribute the data on every destination partition uniformly. While in the case of partitioning with key we can have large data skew due to large key volume, in the case of using round robin partitioning the skew is zero.

What is the definition of a multistage component?

It is a transform component in which we find different packages.

What are the supported layouts in Ab Initio?

In Ab Initio, the supported layouts are the serial and the parallel and a graph can include them both. The parallel layouts is related to the parallelism degree.

What can we say about the Scan component versus a RollUp component?

Scan components make a total series of records while RollUp components summarize groups of data records.

What is the meaning of a DB config versus a CFG file? Ab Initio Interview Questions and Answers

The similarity between these two types is that they are both used for database connectivity. The difference is the usage in Informix Database of the CFG file type and the DB config files are used in SQL Server or Oracle.

How the term Standard Environment can be explained?

The Standard Environment is the type of environment with more than one project that is private and another public one.

How much memory do we need for a graph?

Some calculations lead to approximately eight MB plus the MAX_CORE and the phase file size.

What is the meaning of EME?

As the initials for Enterprise Meta Environment EME is a data repository or a version controller in AB Inition. It is capable of doing a lock and keeps track of graphs or other objects.

What meaning has lock in Ab Initio?

A graph must be locked in order to give permission only to the developer for editing it or the objects that belong to the graph. When other users try to lock the graph they will be warned on the monitor that another user has already made a lock. This is a protection mechanism for developers.

Can a graph be infinitely run? If yes, how? Ab Initio Interview Questions and Answers

Yes it can, by calling the .ksh file in the end of the script.

What is the component that can be used to lower a file in size?

The components that can be used are Deflate and Compress.