Comments on: What does JOIN_BY_SQL do?

By: Dave Rathbun

Dave Rathbun — Mon, 21 Sep 2009 17:07:14 +0000

I can only speculate as I don’t know for sure.

Typically when Business Objects introduces a new parameter they leave it off unless it’s adressing a specific bug. The reason for that would be they have no idea how it’s going to impact all of the client universes on multiple different platforms. It is also possible for this parameter to have a negative impact on performance.

The primary advantage of this feature was posted in comment #10 earlier.

By: Rakesh_K

Rakesh_K — Mon, 21 Sep 2009 11:02:24 +0000

Hi Dave,

Can you put some light on disadvantage of this parameter. Why by default it’s not been set by BusinessObjects itself.

By: Shiva

Shiva — Tue, 25 Aug 2009 17:38:08 +0000

Thankyou Andreas.

Thankyou Dave.

By: Dave Rathbun

Dave Rathbun — Tue, 25 Aug 2009 14:12:00 +0000

JOIN_BY_SQL can have a performance impact but the primary function is to provide multi-pass SQL capabilities to tools (like Crystal) that don’t otherwise support it.

By: Andreas

Andreas — Tue, 25 Aug 2009 09:40:02 +0000

@Siva:
It will create just ONE microbe at the report level, thereby increasing performance.
And would do you mean exactly by: “not giving the right result”, please?

By: Shiva

Shiva — Tue, 25 Aug 2009 05:58:30 +0000

Hi Dave,

After reading your blog i know that JOIN_BY_SQL is different from Synchronize…..in term of performance(for large amount of data) as it occurs at database level.

But what are the other benefits from it?
Could you plase give another small example on what kind of problems it can resolve(Consider a real time DW scenario)? What is the best substitute for this if this is not giving the desired result?

Thanks a ton.

Regards,
Shiva

By: Dave Rathbun

Dave Rathbun — Sun, 16 Aug 2009 15:21:28 +0000

Ganesh, thanks for your comment. As I am sure you realize, if you do a left join you’re not getting the same results. In my opinion, full outer join is the proper syntax to use for this feature. It is designed to replace the data provider synchronization; if you need some other result then you probably need to investigate views or derived tables or some changes to your ETL.

By: Ganesh

Ganesh — Mon, 10 Aug 2009 13:34:01 +0000

Hi Dave,

Thanks for this useful information. It’s really very useful. But just want to know if there is any way to use LEFT OUTER JOIN or RIGHT OUTER JOIN instead of FULL OUTERJOIN in this case. We have some performance issues with FULL OUTER JOIN. If I modify the same query to use LEFT OUTERJOIN it just takes 2 minutes whereas the FULL OUTERJOIN query takes around 20 min…

Please share your inputs or any alternatives available.

Thanks!

By: Dave Rathbun

Dave Rathbun — Thu, 23 Jul 2009 19:18:26 +0000

The standard is to do a FULL OUTER JOIN in order to replicate what Web Intelligence does. In all the times I have used this, I have wanted a full outer join. I can’t think of any reasons off the top of my head to want to change this.

By: Udi

Udi — Thu, 23 Jul 2009 12:32:53 +0000

Hi, and thanks for your posts, Dave.
A question I have – the combination between the queries is with FULL OUTER JOIN.
Can that behavior be changed to combine the queries with INNER JOIN ?
This cause us lots of troubles…

Thanks !