Stable sort option in sort stage

[mallikharjuna]

Hi All,

in sort stage for stable sort option if we select it false, is there any effect on the performance? If it effects please explain how it will effect on performance.


Thanks in Advance

[asorrell]

Stable sort means "if you have two or more records that have the same exact keys, keep them in the same order on output that they were on input".

Since keeping track of relative record location means more work, setting Stable to "False" will speed up performance.

[mallikharjuna]

Thanks asorrell

But what is the use of sort stage Stabe check box in input tab

[chulett]

He explained that. If there's a part in there that is unclear, let us know what.

[mallikharjuna]

In two places i saw stable sort option

1) in Stage>Properties>options>stable sort(true or False)

2) input tab we have to select one check box (perform sort or stable or unique)

My question is what is the difference between these two?

Regards
Mallikharjuna Reddy

[ray.wurlod]

The Stable Sort check box allows one to assert that the sort specified on the input link is (or is not) to be a stable sort.

[dsuser_cai]

When you set stable sort to true the input (non key column) sort order is maintained, when you set it to false the sort order is not maintained. basically its used to maintain the order of Non key columns.