Joiner Transformation Master Detail

Suppose you have 2000 records in one table and 12000 in another which one you will consider as master and detail?

Questions by sarun5   answers by sarun5

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ghola  

  • Member Since Jul-2008 | Aug 15th, 2008

The joiner transformation compares each row of the master source against the detail source. Hence, fewer number of rows in master means fewer iterations of join comparison.

Secondly It is easier to cache the table with fewer number of rows.

Hence, using the table having the fewer number of rows as a master improves the performance.

Showing Answers 1 - 11 of 11 Answers

Sreeya

  • Feb 19th, 2008
 

We will consider the one with lesser number of records as master as with this approach the data to be cached would have to be less and hence the performance can be improved.

ghola

  • Aug 15th, 2008
 

The joiner transformation compares each row of the master source against the detail source. Hence, fewer number of rows in master means fewer iterations of join comparison.

Secondly It is easier to cache the table with fewer number of rows.

Hence, using the table having the fewer number of rows as a master improves the performance.

samirdesai999

  • Jan 14th, 2009
 

We should consider cardinality (lesser number of unique records) on joining conditions for master rather then falling into straight statistics of rowcounts..!!
-- Sam

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Anindya1281

  • Apr 14th, 2010
 

There can be two types of input to a jnr transformation

1) sorted i/p
2) unsorted i/p

In case of un sorted i/p always its better to use smaller table as Master
In case of sorted i/p the table with less number of duplicate key should be taken as MAster

ram_infa

  • Sep 13th, 2011
 

The table with 2000 will be considered as a mater table and table with 12000 considered as detail table caz the joiner transformation compares master data against detail so less no of iterations means less joins thus it enhances the speed or performance

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ponnana

  • Mar 11th, 2014
 

What if there are 200 records in both tables but one table is having 20 columns and other table has 40 columns is present. In this scenario which table has to be chosen as master n detail. Please clarify.

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Rashmi

  • Oct 18th, 2015
 

The join is happening based on some condition. Therefore match process depends on the condition columns only and not how many columns are present in total. The table you drag into joiner first is considered as Master.

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Raju R

  • Oct 27th, 2015
 

@ponnana: The performance of the joiner depends on the rows and not on the columns. Also you take up the condition which consists n number of columns. Based on the condition the rows are obtained. So We need not worry about the columns.

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