Comments on: What does JOIN_BY_SQL do?

By: Neeta

Neeta — Mon, 02 May 2011 14:50:13 +0000

Hi Dave,

Thanks for the detailed information.
I have an observation. When I create a similar query as above using Query Panel from within the Designer I get “Incompatible Combination of Objects” error whereas the query runs successfully whether JOIN_BY_SQL is Yes or No from Webi. I checked the SQL from Query Panel in designer and I can see two select statements which is case in Webi also if JOIN_BY_SQL = No but webi generates no error of incompatible objects. Why so?

Thanks,

By: Dave Rathbun

Dave Rathbun — Fri, 13 Aug 2010 13:29:20 +0000

Whether you use JOIN_BY_SQL or not, the data providers will still run serial.

By: gobinath

gobinath — Fri, 13 Aug 2010 07:39:33 +0000

Hi,
I have single report with multiple data providers(same database(3 sql)),I want to know if i schedule this report to user it will run parallel or serial.Shall i see the execution,If its is run serially is there any possibility to make it as parallel.

My report take more than 3 hours to run how can i reduce the time

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.