21.What is meant by Teradata Gateway?

Just like channel driver, Teradata Gateway acts as a medium of communication between the Parse Engine and applications that are attached to network clients. Only one Gateway is assigned per node.

22.What is meant by a Virtual Disk?

Virtual Disk is basically a compilation of a whole array of cylinders which are physical disks. It is sometimes referred to as disk Array.

23.Explain the meaning of Amp?

Amp basically stands for Access Module Processor and happens to be a processor working virtually and is basically used for managing a single portion of the database. This particular portion of database cannot be shared by any other Amp. Thus, this form of architecture is commonly referred to as shared-nothing architecture.

24.What does Amp contain and what are all the operations that it performs?

Amp basically consists of a Database Manager Subsystem and is capable of performing the operations mentioned below.

• Performing DML
• Performing DDL
• Implementing Aggregations and Joins.
• Releasing and applying locks, etc.

25.What is meant by a Parsing Engine?

PE happens to be a kind Vproc. Its primary function is to take SQL requests and deliver responses in SQL. It consists of a wide array of software components that are used to break SQL into various steps and then send those steps to AMPs.

26.What do you mean by parsing?

Parsing is a process concerned with analysis of symbols of string that are either in computer language or in natural language.

27.What are the functions of a Parser?

A Parser: –

• Checks semantics errors
• Checks syntactical errors
• Checks object existence

28.What is meant by a dispatcher?

Dispatcher takes a whole collection of requests and then keeps them stored in a queue. The same queue is being kept throughout the process in order to deliver multiple sets of responses.

29.How many sessions of MAX is PE capable of handling at a particular time?

PE can handle a total of 120 sessions at a particular point of time.

30.Explain BYNET?

BYNET basically serves as a medium of communication between the components. It is primarily responsible for sending messages and also responsible for performing merging, as well as sorting operations.

31.What is meant by a Clique?

A Clique is basically known to be an assortment of nodes that is being shared amongst common disk drives. Presence of Clique is immensely important since it helps in avoiding node failures.

32.What happens when a node suffers a downfall?

Whenever there is a downfall in the performance level of a node, all the corresponding Vprocs immediately migrate to a new node from the fail node in order to get all the data back from common drives.

33.List out all forms of LOCKS that are available in Teradata.?

There are basically four types of LOCKS that fall under Teradata. These are: –

• Read Lock
• Access Lock
• Exclusive Lock
• Write Lock

34.What is the particular designated level at which a LOCK is liable to be applied in Teradata?

• Table Level – All the rows that are present inside a table will certainly be locked.
• Database Level Lock – All the objects that are present inside the database will be locked.
• Row Hash Level Lock – Only those rows will be locked which are corresponding to the particular row.

35.In the Primary Index, what is the score of AMPs that are actively involved?

Only one AMP is actively involved in a Primary Index.

36.In Teradata, what is the significance of UPSERT command?

UPSERT basically stands for Update Else Insert. This option is available only in Teradata.

37.Highlight the advantages of PPI(Partition Primary Index).?

PPI is basically used for Range-based or Category-based data storage purposes. When it comes to Range queries, there is no need of Full table scan utilization as it straightaway moves to the consequent partition thus skipping all the other partitions.

38.Give the sizes of SMALLINT, BYTEINT and INTEGER.?

39.What is meant by a Least Cost Plan?

A Least Cost Plan basically executes in less time across the shortest path.

40.Highlight the points of differences between the database and user in Teradata.?

• A database is basically passive, whereas a user is active.
• A database primarily stores all the objects of database, whereas a user can store any object whether that is a macro, table, view, etc.
• Database does not has password while the user has to enter password.