Which two system variables/techniques must be used in a parallel Transformer derivation to generate a unique sequence of integers across partitions? (Choose two.)
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@INROWNUM+1
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@INROWNUM
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@PARTITIONNUM
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@NUMPARTITIONS
To generate unique integers across partitions in a parallel Transformer, you need @PARTITIONNUM (identifies the current partition number, typically 0-indexed) and @NUMPARTITIONS (total number of partitions). A common formula is @INROWNUM + @PARTITIONNUM * @NUMPARTITIONS, which ensures each partition generates a non-overlapping sequence. Using @INROWNUM alone only generates sequential numbers within each partition, causing duplicates across partitions.
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.