SSIS creates empty flat fie, how to avoid that?

Question

I have a simple SSIS data export package - Data Flow task which takes data from db table and puts it in a flat file.
SQL Agent is used to run this SSIS data export package every 2 minutes.
Sometimes table is empty, does not have new rows that's why
1 - empty file is being created
2 - SQL Agent gave an error:  The step did not generate any output.  The return value was unknown.  The process exit code was -1073741819.  The step failed.,00:00:02,0,0,,,,0
I placed a "Execute SQL Task" step to count rows in the source table and
disable Data Flow task
if user::count==0  - this still creates an empty file.
Is there a proven workaround to use count variable and actually
disable Data Flow task and avoid creating empty flat file???
Are there any specific rules in setting up "result name" in "SQL Task" "result set" where you map Result Name and Variable Name?
Should it be column name, like "count" for select count(abc) as
count from TABLE
Thank you in advance!

Answer 1

Question about Precedence Constraint - should this work?
In control flow:
1st task
"Execute SQL Task" step to count rows in the source table
Next - Precedence Constraints - Expression - @[User::count]==0 (what should happen
with 2nd task if expression condition is met?)
2nd task: Data Flow which actually exports data from db and puts it into flat file.
In this scenario empty file is still being created...is there something wrong with my Precedence
Constraints - Expression - @[User::count]==0?
Brba,
Yes, there are 2 methods:
method1
Have the sql inside a execute sql task and obtain the rowcount into a variable. if the rowcount is greater than 0 then proceed to data flow task which will then execute sql
again and push data into flat file.
So you may set the precedence of the flow from Execute Sql task to Data flow task as an expression as :
@[User::Count]>0
i.e., only if its greater than zero, will the control even reach the DFT.
MEthod2
Similar method using @count variable. Have a data flow task followed by a file system task.
Inside the DFT, have the Rowcount transformation between the source and destination that would obtin rowcount into @count variable.
Now similar to above method, set precedence of the path (connnecting DFT and File System task) as expression such that @[User::Count] <=0 . So if rowcount IS zero, will reach FST - wherein you may program as DELETE FILE and select connection as flatfile
conenction manager itself.
Thanks,
Jay
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