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databases Online Quiz - 41

Description: databases Online Quiz - 41
Number of Questions: 20
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Tags: databases
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How the monitor program should be written

  1. A monitor program which dispatch the events to the callback of the one of the member

  2. Monitor object with it's own callback function

  3. A monitor program which dispatch the events to the callback of the member of

  4. None


Correct Option: B

The maximum number of action tokens that a fault tolerance member callback function can receive

  1. 1

  2. 2

  3. 3

  4. 5


Correct Option: C

If CM Sender sends message to a ordinary listener which of the following will happen?

  1. listener discards the labelled part of the message but process the data

  2. listener discards the Sequence no of the first message

  3. listener listens the labelled message and confirms it

  4. listener doesn't listen for the message at all


Correct Option: A

Q1,Q2,Q3 are three diff Queues which are in a queue group with same pririty in each of the queue. there are two events in each of the queues. Whcih one of the following will happen?

  1. Q1, Q2 will have one event each and Q3 don't have any events

  2. Q2, Q3 will have one events each and Q1 don't have any events

  3. Q1, Q2 won't have any events and Q3 will have 2 events

  4. the scenario is unpredictable


Correct Option: D

The callback function of a timer with an interval of 5 seconds, sleeps for a period of 20 seconds. The timer events are dispatched in three threads .A statement at the start of the callback function prints out a message to the screen. What is the time difference between two consecutive messages output to the screen ?

  1. 5s

  2. 20s

  3. 25s

  4. 10s


Correct Option: A

The callback function of a timer with an interval of 5 seconds, sleeps for a period of 20 seconds. The timer events are dispatched in a single thread .A statement at the start of the callback function prints out a message to the screen. What is the time difference between two consecutive messages output to the screen ?

  1. 5s

  2. 25s

  3. 10s

  4. 20s


Correct Option: D

What are the parameters for creating a timer event object ? Choose 3.

  1. queue

  2. callback

  3. interval

  4. transport


Correct Option: A,B,C

Choose the two similar scenarios out of the following :

  1. poll and timed dispatch of 0

  2. dispatch and timed dispatch of –1

  3. poll and timed dispatch of –1

  4. dispatch and timed dispatch of 0


Correct Option: A,B

The following are the fields of a message. Which field will be removed when you remove field by giving field name A and field instance 2 ? Field name Field value Field id A “default” 0 A “abc” 1 A “1,2,3,4” 2

  1. All occurrences of field A

  2. 2nd occurrence of field A

  3. 2nd element of the array in the third occurrence

  4. None


Correct Option: B

Which three statements are true about File Sets? (Choose three.)

  1. File sets are partitioned.

  2. File sets are unpartitioned.

  3. File sets are stored as a single file.

  4. File sets are readable by external applications.


Correct Option: A,D

Which three lookup types may be performed in the Lookup stage? (Choose three.)

  1. Equality match

  2. Negative match

  3. Range on stream link

  4. Range on the reject link


Correct Option: A,C,D

What is the lowest CPU cost partitioning method for parallel stage to parallel stage?

  1. Range

  2. Modulus

  3. Entire

  4. Same


Correct Option: D

AI Explanation

To answer this question, we need to understand the different partitioning methods used in parallel processing.

A partitioning method determines how data is divided and distributed among multiple parallel stages. The goal is to distribute the workload evenly across the parallel stages to achieve efficient parallel processing.

Let's go through each option to understand why it is correct or incorrect:

Option A) Range - This option is incorrect. Range partitioning involves dividing the data based on a specified range of values. While it can be effective in certain scenarios, it may not always result in the lowest CPU cost for parallel stage to parallel stage processing.

Option B) Modulus - This option is incorrect. Modulus partitioning involves dividing the data based on the remainder of a division operation. Similar to range partitioning, it may not always result in the lowest CPU cost for parallel stage to parallel stage processing.

Option C) Entire - This option is incorrect. Entire partitioning involves sending the entire data set to each parallel stage. This method can be inefficient as it duplicates the data across multiple stages, leading to higher CPU costs.

Option D) Same - This option is correct. The "Same" partitioning method involves sending the same data to each parallel stage. This method ensures that each stage processes the same data without duplicating it. Since the data is not divided or duplicated, it typically results in the lowest CPU cost for parallel stage to parallel stage processing.

Therefore, the correct answer is D) Same. This option is correct because it offers the lowest CPU cost partitioning method for parallel stage to parallel stage processing.

A DataStage job is sourcing a flat file which contains a VARCHAR field. This field needs to be mapped to a target field which is a date. Which will accomplish this?

  1. Use a Column Exporter to perform the type conversion.

  2. DataStage handles the type conversion automatically

  3. Use the TimestampFromDateTime function in a Transformer.

  4. Use the Modify stage to perform the type conversion.


Correct Option: D

AI Explanation

To answer this question, we need to understand how DataStage handles type conversion when mapping a VARCHAR field to a date field.

Option A) Use a Column Exporter to perform the type conversion. This option is incorrect because a Column Exporter is used to export data from DataStage to an external target, not for performing type conversions within DataStage itself.

Option B) DataStage handles the type conversion automatically. This option is incorrect because DataStage does not automatically handle type conversions. It is important to explicitly convert data types to ensure accurate mapping and processing.

Option C) Use the TimestampFromDateTime function in a Transformer. This option is incorrect because the TimestampFromDateTime function is used to convert a DateTime field to a Timestamp field, not a VARCHAR field to a date field.

Option D) Use the Modify stage to perform the type conversion. This option is correct because the Modify stage in DataStage allows for data transformation and type conversion. By using the Modify stage, you can convert the VARCHAR field to a date field.

The correct answer is D) Use the Modify stage to perform the type conversion. This option is correct because the Modify stage can be used to convert the VARCHAR field to a date field.

Which Oracle Enterprise stage read property can be set using db options to tune job performance?

  1. memsize

  2. arraysize

  3. partitionsize

  4. transactsize


Correct Option: B

AI Explanation

To answer this question, you need to understand the different Oracle Enterprise stage read properties and how they can be used to tune job performance.

Option A) memsize - This option is incorrect. The "memsize" property is used to specify the amount of memory available to the Oracle Enterprise stage for buffering data. It does not directly impact job performance tuning.

Option B) arraysize - This option is correct. The "arraysize" property can be set using database options to tune job performance. It specifies the number of rows that are fetched from the database server in each round trip. By increasing the arraysize, more data can be fetched in a single round trip, which can improve the performance of the job.

Option C) partitionsize - This option is incorrect. The "partitionsize" property is used to control how the data is divided into partitions for parallel processing. It does not directly impact job performance tuning.

Option D) transactsize - This option is incorrect. The "transactsize" property is used to specify the number of rows that are processed in each transaction. It does not directly impact job performance tuning.

The correct answer is B) arraysize. This option is correct because increasing the arraysize can improve the performance of the job by fetching more data in each round trip from the database server.

Which import option can be used to import metadata from a data modeling tool such as Erwin or Rational Data Architect?

  1. Import using bridges.

  2. Import a table definition using the Connector wizard.

  3. Import DataStage components.

  4. Import a table definition using the Plug-In Meta Data facility.


Correct Option: A

You need to invoke a job from the command line that is a multi-instance enabled. What is the correct syntax to start a multi-instance job?

  1. dsjob -run -mode NORMAL -instance

  2. dsjob -run -mode NORMAL -wait -instance

  3. dsjob -run -mode NORMAL .

  4. dsjob -run -mode MULTI .


Correct Option: C

Which three property areas must be configured when using the ODBC connector stage as a target in your job design? (Choose three.)

  1. Define the connection properties to an ODBC data source.

  2. Define columns for the output link.

  3. Specify properties for the input link.

  4. Define columns for the input link data.


Correct Option: A,C,D

Which two system variables/techniques must be used in a parallel Transformer derivation to generate a unique sequence of integers across partitions? (Choose two.)

  1. @INROWNUM+1

  2. @INROWNUM

  3. @PARTITIONNUM

  4. @NUMPARTITIONS


Correct Option: C,D

AI Explanation

To answer this question, we need to understand the concept of parallel Transformer derivation and the system variables/techniques used in it.

Parallel Transformer derivation is a process in which data is divided into multiple partitions and processed concurrently by multiple instances of a Transformer stage. Each partition is assigned a unique number, called the partition number, to identify it.

The two system variables/techniques that must be used in a parallel Transformer derivation to generate a unique sequence of integers across partitions are:

C. @PARTITIONNUM - This system variable returns the partition number of the current row. It is used to identify the partition that the row belongs to. Each partition will have a different value for @PARTITIONNUM, ensuring a unique sequence of integers across partitions.

D. @NUMPARTITIONS - This system variable returns the total number of partitions in the parallel Transformer derivation. It is used to determine the total number of partitions and can be used to calculate the range of values for @PARTITIONNUM. The combination of @PARTITIONNUM and @NUMPARTITIONS ensures a unique sequence of integers across partitions.

To summarize: Option A) @INROWNUM+1 - This option is incorrect as it does not generate a unique sequence of integers across partitions. Option B) @INROWNUM - This option is incorrect as it does not generate a unique sequence of integers across partitions. Option C) @PARTITIONNUM - This option is correct as it returns the partition number of the current row, ensuring a unique sequence of integers across partitions. Option D) @NUMPARTITIONS - This option is correct as it returns the total number of partitions, allowing for the calculation of @PARTITIONNUM and ensuring a unique sequence of integers across partitions.

Therefore, the correct answers are C) @PARTITIONNUM and D) @NUMPARTITIONS.

Which action produces the most accurate Table Definitions for usage with the Oracle Enterprise stage?

  1. Use import "Oracle Table Definitions" .

  2. Use import "Via bridges".

  3. Use import "Plug-in Meta Data Definitions".

  4. Use import "Orchestrate Schema Definitions" using orchdbutil.


Correct Option: D
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