databases Online Quiz - 62
|Description: databases Online Quiz - 62|
|Number of Questions: 20|
|Created by: Aliensbrain Bot|
Of the following which is a true statement with regard to a primary index operation?
To answer this question, let's go through each option to understand why it is correct or incorrect:
Option A) When choosing a primary index, you should pick a column with a severely limited value set.
- This option is incorrect. When choosing a primary index, it is generally recommended to pick a column with a broad value set to evenly distribute data across AMPs and optimize performance.
Option B) If distribution is skewed, an all-AMP operation will take longer than if all AMPs were evenly utilized.
- This option is correct. In Teradata, data distribution across AMPs plays a crucial role in achieving optimal performance. If the data distribution is skewed, meaning that some AMPs have significantly more data than others, an all-AMP operation will take longer as the workload is not evenly distributed.
Option C) Selecting a NUPI for storing data provides for maximum efficiency and makes the best use of the parallel features of Teradata.
- This option is incorrect. While selecting a NUPI (Non-Unique Primary Index) can provide some benefits in certain scenarios, it does not necessarily guarantee maximum efficiency or the best use of parallel features. The choice of primary index depends on various factors such as data distribution, workload, and query patterns.
Option D) The degree of uniqueness is not critical to efficiency.
- This option is incorrect. The degree of uniqueness in a primary index is critical to efficiency in Teradata. A highly unique primary index distributes the data evenly across AMPs, allowing for efficient parallel processing. On the other hand, a low degree of uniqueness can lead to skewed data distribution and inefficient query performance.
The correct answer is B) If distribution is skewed, an all-AMP operation will take longer than if all AMPs were evenly utilized. This option is correct because skewed data distribution can lead to imbalanced workloads and slower performance in Teradata.
Which are two exclusive features of Teradata? (Choose two)
You are an administrator at CertKiller.com. CertKiller.com has a Teradata system with 100 GB of permanent space, of which 50 GB is reserved for spool space. The system currently has 30 GB of user data. What is the total available spool space for user queries?
To calculate the total available spool space for user queries, we need to subtract the amount of user data from the reserved spool space.
- Total permanent space = 100 GB
- Reserved spool space = 50 GB
- Current user data = 30 GB
To calculate the available spool space, we subtract the current user data from the reserved spool space: Available spool space = Reserved spool space - Current user data
Substituting the given values: Available spool space = 50 GB - 30 GB Available spool space = 20 GB
Therefore, the total available spool space for user queries is 20 GB.
An example of an OLTP environment is _____
When utilizing a unique secondary index, how may AMP (s) is usually accessed?
How would you define a transaction?
Consider the emp table having columns empno, ename Which of the following SQL query fetches empno that occur more than twice in the emp table.
While creating tables the concept that is used to reduce redundancy in data is called
A table T1 having 100 rows is joined with a table T2 with 50 rows without specifying the joined column in the where clause then result will have
Which normal forms require that non-key columns be functionally dependent solely on the primary key?
Which of the following options is FALSE about unchained mode in ASE