In general, how Tableau Prep handles data from Redshift? Data will be unloaded into Tableau Prep memory, cache the data and then do transformation?
@Emma Chan
Well it depends if you are using several datasources (e.g, some excel files, other data bases) or if you are using only one connection.
If you are using only Redshift as data source: In this case, Tableau Prep, will send a custom sql (probably a big one) to Redshift, it will take some time to Redshift process it, and then Tableau Prep will process the outputs (publish data source, create extracts, publish tables to other databases). Some operations due to data source limitations (functions not supported by the database) could be made in Prep but normally the flow is as I said before.
If you are using several data sources: In this case, Tableau Prep would send custom sqls, to the inner most steps of the flow, and then will store the results locally to make the crossdatabase steps.
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Regards,
Diego
Tableau Ambassador
