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How do linked table parameters work?

Question asked by arosenthal on Apr 3, 2017
Latest reply on Aug 9, 2018 by jking

I have a question about how linked table parameters work internally. I have several tables that query external Oracle databases for data, and these tables are then referenced with Table Lookup Data References (TLDRs) on element attributes. As far as I can see, the TLDRs can select rows from the tables in one of two ways:

 

a) using a WHERE clause in the configuration

b) using table parameters

 

Up until now I have been using the first approach, but I am interested to learn more about the second. If I adopt table parameters, how does the linked table query get executed on the server? I think there are two possible behaviors:

 

1) The linked table is executed once without the parameter in place. All the table data would then be cached internally and the TLDR would then select from this cache by substituting in the appropriate parameter value.

2) The linked table is executed multiple times for every TLDR, with the appropriate parameter value substituted in.

 

I want to try to avoid the second behavior because my concern is it would create too many query executions, since I have so many attributes with TLDRs.

 

Does anyone have any insight into this?

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