A development team is making use of Azure Stream Analytics. They have defined the following SQL query:
WITH step1 AS (SELECT * FROM input1 PARTITION BY XYZID INTO 10), step2 AS (SELECT * FROM input2 PARTITION BY XYZID INTO 10)
SELECT * INTO output FROM step1 PARTITION BY XYZID UNION step2 PARTITION BY XYZID
Does the query represent the joining of two streams of repartitioned data?
A
Yes, this query does represent the joining of two streams of repartitioned data.
An example of this is given in the Microsoft documentation:
The following example query joins two streams of repartitioned data. When joining two streams of repartitioned data, the streams must have the same partition key and count. The outcome is a stream that has the same partition scheme.
The output scheme should match the stream scheme key and count so that each substream can be flushed independently. The stream could also be merged and repartitioned again by a different scheme before flushing, but you should avoid that method because it adds to the general latency of the processing and increases resource utilization.
Reference:
https://docs.microsoft.com/en-us/azure/stream-analytics/repartition
This is a union of 2 streams, not a join.