Ans.
During a session run, the
Integration Service compares each row of the master source against
the detail source.
The master and detail sources need
to be configured for optimal performance.
To improve performance for
an Unsorted Joiner transformation, use the source with fewer
rows as the master source. The fewer unique rows in the master, the fewer
iterations of the join comparison occur, which speeds the join process.
When the Integration Service
processes an unsorted Joiner transformation, it reads all master rows before it
reads the detail rows. The Integration Service blocks the detail source while
it caches rows from the master source. Once the Integration Service reads
and caches all master rows, it unblocks the detail source and reads the detail
rows.
To improve performance for
a Sorted Joiner transformation, use the source with fewer duplicate
key values as the master source.
When the Integration Service
processes a sorted Joiner transformation, it blocks data based on the mapping
configuration and it stores fewer rows in the cache, increasing
performance. Blocking logic is possible if master and detail input to the
Joiner transformation originate from different sources. Otherwise, it does
not use blocking logic. Instead, it stores more rows in the cache.
what is blocking the detail source?
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