LOOP & JOINS IN DATA SERVICES

[srini_cnu]

Hi,

diff. bw loops and joins.

which one is better to data service approach. why?

Regards

Srini

[former_member211387 · Accepted solution]

Hi Srini

Joins are meant used to combine data between different sources for a specific condition and produce output that meet the join criteria. This is similar to a SQL SELECT statement that joins two tables with a WHERE segment that has conditions to match the relevant records. Joins are usually used within dataflows or in scripts.

As far as looping is concerned you repeat the same process more than once for a specific number of times as long as the condition in the loop is met with. In this case you repeat the same process that is within the loop over and over. In a loop you can call the same dataflow or script performing the join as may times as you need.

In case of full pushdown, you can achieve this in your dataflow using more than one performance optimization technique.

1. You can use the data transfer transform

2. or use the pushdown_sql function within the dataflow

3. or you can define the dataflow join condition in such a way that the optimized SQL will result in a INSERT/SELECT statement.

Hope this helps.

Raghu

[Former Member]

Both are entirely different concepts. Whats your requirement? Joins could be pushed down which has some advantages on performance optimization.

[srini_cnu]

Hi Arun,

Joins are which advantages to better than to loop concept. please explain clearly.

which Push down option is there in Joins.

Regards

Srini

[mageshwaran_subramanian]

Your question is unanswerable at this point.You need to clearly frame your question so that you can get an answer.As Arun said , they are two different concepts.What you want to achieve with them?

[srini_cnu]

Hi,

@magesh am asking about joins was which performance optimization are used in data services.

Regards

Srini

[severin_thelen]

Hello Srini,

like Arun Kumar says, joins could be push down. Push down means, that the Data Services could send the task (in this case the join) to the database. That improves the performance, because the database engine could optimize the SQL statement.

But you have to know, that push down need special conditions to work. For more information please read the Performance Optimization Guide.

Regards

Severin

[former_member187605]

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